local action toolkit - urban practitioner's 'toolbox

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LOCAL ACTION TOOLKIT

Ecosystem services in urban water environments

Working with local communities to enhance the value of natural capital in our towns, cities

and other urban spaces to improve people’s lives, the environment and economic prosperity.

Urban Practitioner’s ‘Toolbox’ of Interventions

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CONTENTS:

How to use this toolbox: .............................................................................. 3

Elements of the toolbox: ............................................................................... 3

Elements of the interventions: ..................................................................... 4

The Benefits Indicators: ................................................................................. 5

Interventions Toolbox – Methods: ............................................................. 6

URBAN INTERVENTIONS .......................................................................... 8

Swales ............................................................................................................. 9

Amenity Lawns ............................................................................................ 12

Wetlands ...................................................................................................... 15

Trees ............................................................................................................. 19

Retention Ponds/Basins ............................................................................... 25

Detention Ponds/Basins .............................................................................. 28

Intensive Green Roofs ................................................................................. 31

Extensive Green Roofs ................................................................................ 34

Permeable Pavements ................................................................................ 37

Rainwater Harvesting/Water Butts ........................................................... 40

EXISTING GREEN & BLUE INFRASTRUCTURE ................................. 43

Public Parks and Gardens ........................................................................... 44

Community Gardens & Allotments ........................................................... 48

Urban Rivers ................................................................................................. 53

Private Gardens ........................................................................................... 57

Access ........................................................................................................... 62

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HOW TO USE THIS TOOLBOX:

The toolbox can give you an overview of the benefits of different interventions, guide you towards

further literature and give you examples of where an intervention has been used.

It can also help you make decisions about the right way to intervene in your local environment. The

benefits wheel shows you the relative contribution a certain type of intervention can make to a

specific characteristic of an area. It identifies 12 different benefits, grouped into four categories –

social, environmental, economic and cultural – that influence the quality of life.

Using the toolbox to deliver targeted interventions

ELEMENTS OF THE TOOLBOX:

The toolbox is made up of a number of tools or “interventions”, each with different characteristics.

Most of them work as actual “interventions” (for example, swales) – i.e., they are meant to be

designed and developed specifically for an area to address certain issues, be it as new build or

retrofit – but there are a few that are usually “existing assets” (for example, public parks) – i.e., they

already exist in the urban landscape and are likely under pressure, for example from development.

These two categories are of course not completely exclusive – there may be existing

“interventions” in the landscape that need protection or improvement, or there may be

opportunities to develop new “assets”.

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ELEMENTS OF THE INTERVENTIONS:

Th

e B

en

efi

ts W

heel

The Benefits Wheel constitutes 12 different benefit indicators that can be influenced

by the intervention, grouped into four categories: social, environmental, economic

and cultural. Each of the different benefit indicators is ranked on a scale from 1 to 5,

indicating the impact that the intervention can have on it, compared to other

interventions.

For example, detention basins score a “2” on the benefit “Habitat Network”, while trees

score a “4”. This means that placing trees in the urban landscape can have a greater

positive impact on the development/protection of habitats and biodiversity than building a

detention basin.

This is a semi-quantitative ranking that does not indicate a percentage,

but an indication of the relative contribution the intervention can make

on the provision of a certain benefit. The ranking has been assigned on the

assumption that the intervention is well planned, designed and maintained. Further

information on each of the benefit indicators is given in the detailed “Benefits”

section of the tool factsheet.

On the next page, each of the benefits is explained in detail.

Lan

dsc

ap

e C

on

text

To address not only surface water flooding but most of the benefits represented in

the wheel adequately, you should look at the bigger picture of what you are trying to

do in your area. Look at interventions as part of the landscape and think about how

you can combine them to achieve optimal outcomes.

This is especially important as interventions come in different shapes and sizes and

their respective relative contribution can therefore vary. This section presents

examples and ideas on positioning interventions and indicates their function in

dealing with surface water.

Co

sts,

Main

ten

an

ce a

nd

Feasi

bilit

y

This section gives you more detail on planning aspects of the intervention. If you

know the details of where you would like to install an intervention, you can use this

section to select suitable options and find further guidance. Or, if you would like to

identify suitable options for installing interventions, you can find initial information on

what each intervention needs to work here. More detailed guidance can be found in

various guidance documents, for example the Suds Manual published by CIRIA or

you can check the references of this section.

Costs: indicative capital cost. This can vary due to local factors and should only

be seen as an indication. Some factors influencing capital cost or in some cases

lifetime costs may be given.

Maintenance: Average maintenance costs per unit are given where available or

an indication of magnitude of costs is given. Typical maintenance activities are

indicated. Correct maintenance is crucial to guarantee that the intervention

can deliver, and detailed information should be sought before it is planned and

installed.

Feasibility: Options of fitting intervention (retrofit or new development) are

indicated along with other factors that can influence whether or not an

intervention can be delivered successfully.

Ad

d. B

en

.&

Co

sts

This section gives information on further important benefits that can be gained from

an intervention that are not included in the benefits wheel. It also lays out potential

negative effects it can have.

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THE BENEFITS INDICATORS:

Each of the twelve wedges of the benefits wheel represents one indicator for the provision of benefits through

delivering an intervention or protecting/restoring an existing asset. In the factsheets, details on how the

intervention can do this are given along with their references so you can understand what it is that the

intervention influences. To get a basic understanding of what the indicators mean, read the table below.

Health: Access

Indicates potential to

provide accessible,

attractive green space

(either intervention

itself or designated

area) and the health

benefits arising

thereof, or to improve

accessibility of existing

area

Health: Air

Indicates potential for

air quality improvement

if used optimally, i.e.

wind direction,

pollution sources etc.

are taken into account

Flood (Surface)

Indicates contribution

to reducing surface

water flooding through

either infiltration,

conveyance or storage

of runoff. Higher

numbers have been

assigned to

interventions infiltrating

runoff, since this

reduces the volume of

runoff from the start. *

Flood (Rivers & Sea)


influence flooding from

rivers through

providing storage or

reducing volume of

water the river

receives. Important:

only takes effect

downstream of

intervention! Benefits

are not likely to be felt

locally.

Habitat

Indicates the ability to

provide habitat for a

variety of species

(plants & animals) and

form part of an urban

ecological network

Low Flow

Indicates potential

contribution to

groundwater recharge

or to reduction of

pressure on mains

water

Water Quality

Indicates the ability to

prevent pollution either

through breaking down

pollutants or reducing

polluted runoff

Climate Regulation


regulate local air

temperatures and

store/sequester

carbon.

Cultural Activities

Indicates likelihood to

provide opportunity

for engagement in

cultural activities

and/or experience

cultural values

Aesthetics

Indicates aesthetic

value of intervention

itself and contribution

to appearance of local

area

Property Value

Indicates potential

impact on increasing

value of property

Flood Damage

Indicates contribution

intervention can make

to reducing severity of

flooding (both from

rivers and surface

water) and therefore

damage done

*Surface water flooding is a complex problem, that is not easily represented in one number. It can be mitigated by

reducing the volume of water, i.e. infiltrating it or storing it immediately at the source, by leading the water away from

vulnerable areas or by collecting it from a bigger area and storing it. For the purposes of this toolbox, the three options

are presented on the same scale. It is therefore important to understand what the main issues you are facing are, i.e.

where does the water that is causing a problem come from. If you want to control water locally, interventions providing

infiltration may be best suited, but if you are looking to a larger scale, these interventions may not be able to fulfil your

requirements and you may prefer options storing water. A good way to understand this is by using the SuDs approach

regarding site, local and regional control. An indication of where a certain intervention fits in is given in the “Landscape

context” section.

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INTERVENTIONS TOOLBOX – METHODS:

General Approach

The list of interventions was compiled by reviewing existing typologies of green infrastructure components and

sustainable drainage systems. They were categorised into “existing assets” and “interventions” based on the

likelihood of being implemented as a new feature. Parks, allotments, urban rivers/watercourses and private

gardens were classed as “existing assets” as they are usually under pressure from various factors, for example

new development. While their size or number may be increased in some cases, it is more often the case that

existing ones have to be protected (see for example Smith, 2010; Heritage Lottery Fund, 2014). Throughout

the process of collating information, the list of interventions was modified in order to allow for interventions

with similar features to be treated together, making the toolbox more manageable and easier to use.

Information was collated from a variety of sources in the grey as well as academic literature. Grey literature

was mostly used to provide initial information and signposting to academic publications, but also as a source in

its own right, especially where it was published by accredited organisations such as Forest Research or the

Environment Agency. A semi-structured literature review using the snowball method was carried out to gain a

broad range of information on each intervention respectively. Especially information on costs and maintenance

was taken mainly from grey literature, as this is not a topic academic publications are usually concerned with.

Additionally, the Natural England Ecosystem Services Transfer Toolkit and the SuDS Manual (Kellagher et al.,

2015) was used to provide an overview as well as limited validation of findings where it was suitable.

Benefits Wheel Indicators

To allow comparability and consistency throughout the use of the output from the Local Action Project, and

to make the use of the toolbox as simple as possible, the same twelve indicators for benefits were used to

describe interventions as for the GIS based needs assessment.

The indicators are given a ranking from 1 to 5 based on the ability of an intervention to increase the provision

of certain ecosystem services/benefits from ecosystem services in the urban landscape. This describes its ability

to increase a benefit compared to other interventions, with 1 signifying “low/unlikely” and 5 signifying

“high/very likely”. Benefit indicators are semi-quantitative measures that allow comparison between different

interventions, but not the quantification of the increase of a benefit or the ability to add benefits together. It

does also not allow comparison of benefit indicators within a wheel. For example: this means that an

intervention ranked 1 on the benefit indicator “Cultural Activities” and 5 on “Aesthetics” is unlikely to

contribute to the provision of opportunities for cultural activities, compared to an intervention that is ranked

5. It does not mean that the intervention contributes 5 times as much to an aesthetically pleasing environment

than to providing opportunity for cultural activities.

The rankings are based on the collated literature. The value given to each indicator was based on set of

characteristics and their comparison within the different interventions. Literature was identified specific to

each intervention, however where it was likely that findings could be transferrable (e.g. due to similar

characteristics in one aspect), and information on a specific intervention was not easily available, evidence that

was not specific to the intervention was accepted. For each indicator, a number of sources were used where

possible to provide an overall estimate of the performance of the intervention. More weight was given to

academic literature reviews and grey literature from accredited sources presenting evidence, but case study

evidence and academic papers were used to complement these.

As a measure of confidence, a “traffic light” system was used to indicate the evidence base the ranking was

based on. Each of the indicators on each intervention was given an asterisk in red, amber or green, designating

a level of certainty: red meaning little availability of and/or high uncertainty within the literature; amber

meaning mainly positive evidence in the literature but little literature available or sometimes uncertainty in

literature; green meaning that a strong evidence base confirms the positive influence of the intervention.

Table 1 gives an overview of each indicator and its characteristics.

Limitations

While the approach taken was similar to a structured literature review, it did not use the same methods of

classifying and weighing different sources in a structured way. Due to time constraints, the literature used was

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limited although a high number of sources was identified and through the use of established sources of grey

literature and existing reviews, the overall coverage of evidence should be sufficiently high. This does mean

however that opportunities to showcase the multiple and varied benefits that different features of green

infrastructure can provide may have been missed. This is even more likely as green infrastructure is a very

broad and fluid concept that is dealt with by the academic community using a number of different disciplines,

terminologies and approaches. This makes it difficult to gather all relevant data within a limited amount of time.

Additionally, while efforts were made to include broader literature and evidence on urban ecosystem services

in general and green infrastructure more specifically, the literature search was focussed on identifying benefits

that could be linked to specific interventions, potentially missing evidence that was not clearly related to them.

While the semi-quantitative ranking is based on a comparison of evidence, it is still biased as evidence is

weighed by the researcher, influencing the ranking. To make this evident to the user and to enable further

referencing, the confidence measurements were used.

Indicator Description Evidence used

Health: Access potential to provide accessible, attractive

green space (either intervention itself or

designated area) and the health benefits

arising thereof, or to improve accessibility

of existing area

Evidence on positive health impacts linked to specific intervention,

evidence on use of intervention for physical activity, evidence on

potential to provide accessible green spaces, evidence to increased

use of greenspaces due to intervention

Health: Air potential for air quality improvement if used

optimally, i.e. wind direction, pollution

sources etc. are taken into account

Evidence on pollutant removal of specific or similar intervention,

evidence on air quality, evidence on air quality related health

benefits

Flood (Surface) contribution to reducing surface water

flooding through either infiltration,

conveyance or storage of runoff. Higher

numbers have been assigned to

interventions infiltrating runoff, since this

reduces the volume of runoff from the start

Evidence on infiltration rates and volume reduction, evidence on

peak flow attenuation, evidence on storage. This is a very difficult

indicator as surface water flooding can be mitigated in various

ways and on various scales. Using a single number to represent

this is difficult. Awareness of the detailed description given is

therefore important as well as of the causes and symptoms of the

surface water flooding situation one is trying to tackle using these

interventions.

Flood (Rivers &

Sea)

Indicates potential to influence flooding

from rivers through providing storage or

reducing volume of water the river receives

Evidence on ability to influence flood management and reduction

of runoff of intervention itself or similar interventions

Habitat Indicates the ability to provide habitat for a

variety of species (plants & animals) and

form part of an urban ecological network

Evidence for species numbers and species rareness found linked to

intervention, evidence for habitat value, evidence for use as

stepping stones

Low Flow Indicates potential contribution to

groundwater recharge or to reduction of

pressure on mains water

Evidence for infiltration and groundwater recharge, evidence for

flow regulation, evidence for decreased use of mains water

(ultimately reducing abstraction) of intervention itself or similar

interventions

Water Quality Indicates the ability to prevent pollution

either through breaking down pollutants or

reducing polluted runoff

Evidence for infiltration of polluted runoff (reducing amount of

pollutants reaching surface water), evidence on breakdown of

pollutants in intervention, evidence of reduced pollutants in runoff

Climate

Regulation

Indicates potential to regulate local air

temperatures and store/sequester carbon.

Evidence on reducing temperatures, evidence of positive impact

on UHI, evidence on carbon sequestration/storage in intervention

or similar interventions

Cultural

Activities

Indicates likelihood to provide opportunity

for engagement in cultural activities and/or

experience cultural values

Evidence on cultural values connected to intervention, evidence

on activities relating to cultural benefits, evidence on use of

intervention as meeting points

Aesthetics Indicates aesthetic value of intervention

itself and contribution to appearance of

local area

Evidence on aesthetic value of intervention, evidence on

opportunity for design and creation

Property Value Indicates potential impact on increasing

value of property

Evidence on increased property values linked to intervention or

similar interventions

Flood Damage Indicates contribution intervention can

make to reducing severity of flooding (both

from rivers and surface water) and

therefore damage done

Combination of evidence on surface water flooding and fluvial

flooding, taking into account the scale on which the intervention

works

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URBAN

INTERVENTIONS

Image: John Lord (CC BY 2.0)

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SWALES

Swales are linear, shallow channels designed to collect and convey rainwater. They also provide pollutant

removal and infiltration to some extent. Vegetation and sedimentations removes suspended solids, dissolved

pollutants infiltrate with the water into the soil and can so be removed. Three types of swale can be

distinguished: Attenuation/conveyance swales, dry swales and wet swales. They each are designed to optimise

different aspects of water management. Attenuation/conveyance swales usually do not provide treatment or

amenity/ecological benefits, they resemble conventional drainage ditches. Dry swales can be grassed and then

are more resembling conventional drainage ditches as well, providing less treatment and flow reduction, or

vegetated. Vegetated swales usually feature high grasses and shrubby vegetation, slowing water flow and

enabling sedimentation as well as providing more visual and ecological benefits.

Benefits Wheel

Landscape context

Shows the contribution of swales to the provision of ecosystem services.

More detail on the next page.

In the landscape, swales act as connecting elements

between other elements of rainwater treatment. While

they do provide some storage and treatment, they are

best suited to accept runoff from an area – for example, a

car park – and lead it into further structures like

detention basins or ponds. They can replace conventional

pipework in this function.

Whether swales can only work as conveyance or also to

reduce/treat runoff is determined by the infiltration

capacity of the soil. They are ideal for industrial sites as

pollution incidents are easily visible. Downstream

treatment components should be incorporated.

Costs Maintenance Feasibility

£10-20/m2. Medium land take, linear

structures allow high adaptability. (7)

£0.1/acre for regular maintenance,

marginally higher for remedial or

intermittent maintenance. Mowing,

litter and debris removal. Clearing of

inlets and outlets. May need removal of

sediment. Can be included in

landscaping costs. (7)

Retrofit & high density development

possible. Land take limits suitability.

Performance depends on the length of

the swale in flow direction and

vegetation. Hydraulic connectivity must

be ensured, not suitable for steep areas

or large amounts of storm water and

high pollution. (1,9)

Featu

red

Case

Stu

dy

Hollington Primary School, Hastings

This school on a sloping site had suffered considerable flood damage due to

overland flows entering the site from residential areas above. Additionally,

residential parts of the catchment below the school are also prone to

flooding and run off from and passing through the school site is a

contributory factor. The SuDS intercept these flows and divert them, over

land, to a system of storage, conveyance and flow control comprising an

innovative playground storage area, storage swales and rain garden basins

that create a dynamic school environment with enhanced learning potential

and increased biodiversity.

More: http://www.susdrain.org/case-

studies/case_studies/hollington_primary_school_hastings.html

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Social Benefits Environmental Benefits

Health: Access. * Depends on the design of the swale and

its surroundings, but swales can provide accessible small

greenspaces. This is often in the context of a larger green

area and the impact of the swale itself can therefore not be

seen separately. (1)

Air Quality. * Vegetation of any kind takes up pollutants

from the air. Closely mown grass is unlikely to contribute

significantly. (14)

Surface Water. * Swales can infiltrate 40% of all rainfall

events and reduce runoff for an additional 40%, with an

overall volume reduction of 50-60% - often low peak

discharge or volume control provided by swales. This

depends on their design. (1,2,6,9,11,12,13)

Fluvial Flood. * Swales have no impact on fluvial flooding.

Water Quality. * Swales perform well removing TSS (usually

above 65%) and metals but less for nutrients (30-40% or less,

with P showing better removal than N). Fine particles are

often not captured. Accumulation of pollutants can be a

problem. Vegetated swales are sometimes said to perform

better.(2,4,5,9,10,13)

Habitat Provision. * Can function as green corridors and

provide habitat to different species. Especially use of native

plants and varied vegetation is valuable. (1,8)

Climate Regulation. * Evaporation can have positive effects

on UHI effect. Little carbon storage possible.(15)

Low Flows. * Groundwater recharge is usually provided, but

care has to be taken to prevent pollution. Water from swale

can be discharged into streams and so directly improve low

flows – depends on water quality. (1,13)

Cultural Benefits Economic Benefits

Aesthetics. * Depends on design. Higher growing native

vegetation can provide interesting meadow-like appearances.

Meandering swales have a more natural look. The design can

easily be adapted to suit surroundings. (1, 9)

Cultural Activities. * Can be used as an educational

resource, design of the swale should take this into account.

Case studies have demonstrated the use of swales as

“outdoor classrooms” etc. (1, 9)

Property Value. * Swales are unlikely to contribute much to

property value.

Flood Damage. * Through their impact on reducing and

removing surface water runoff, swales can reduce severity of

surface water floods.

Additional Benefits and Potential Costs

No additional benefits Water quality. In peak events, nutrients and metals can be

released from the swale and reach watercourses. Correct

design and maintenance should work to prevent this.

Aesthetics. If maintenance and plant selection is not careful,

the swale’s appearance could deteriorate. For swales near

roadsides, salt resistant plants should be chosen to be able to

survive de-icing in winter.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature

available. * Varying results in literature, little literature available

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References:

(1) http://www.susdrain.org/delivering-suds/using-

suds/suds-components/swales-and-conveyance-

channels/swales.html

(2) Ahiablame, L. M., Engel, B. A. and Chaubey, I. (no

date) Effectiveness of Low Impact Development

Practices: Literature Review and Suggestions for

Future Research.

(3) Ashley, R. M., Nowell, R., Gersonius, B. and

Walker, L. (2011) ‘Surface Water Management and

Urban Green Infrastructure’, 44(0), pp. 1–76.

(4) Berwick, N. and Wade, D. R. (2013) A Critical

Review of Urban Diffuse Pollution Control :

Methodologies to Identify Sources , Pathways and

Mitigation Measures with Multiple Benefits.

(5) Deletic, A. (2005) ‘Sediment transport in urban

runoff over grassed areas’, Journal of Hydrology,

301(1-4), pp. 108–122.

(6) Ellis, J. B., Shutes, R. B. E. and Revitt, M. D. (2003)

Constructed Wetlands and Links with Sustainable

Drainage Systems.

(7) Environment Agency (2015) Cost estimation for

SUDS - summary of evidence. Bristol.

(8) Kazemi, F., Beecham, S. and Gibbs, J. (2011)

‘Streetscape biodiversity and the role of

bioretention swales in an Australian urban

environment’, Landscape and Urban Planning,

101(2), pp. 139–148.

(9) Kellagher, R., Martin, P., Jefferies, C., Bray, R.,

Shaffer, P., Wallingford, H. R., Woods-Ballard, B.,

Woods Ballard, B., Construction Industry Research

and Information Association, Great Britain,

Department of Trade and Industry and

Environment Agency (2015) The SUDS manual,

CIRIA. London.

(10) Lucke, T., Mohamed, M. and Tindale, N. (2014)

‘Pollutant Removal and Hydraulic Reduction

Performance of Field Grassed Swales during Runoff

Simulation Experiments’, Water. Multidisciplinary

Digital Publishing Institute, 6(7), pp. 1887–1904.

(11) Pratt, C. J. (2004) Sustainable Drainage. A Review

of Published Material on the Performance of

Various SUDS Components. Bristol.

(12) Qin, H., Li, Z. and Fu, G. (2013) ‘The effects of low

impact development on urban flooding under

different rainfall characteristics.’, Journal of

environmental management, 129, pp. 577–85.

(13) Stagge, J. H., Davis, A. P., Jamil, E. and Kim, H.

(2012) ‘Performance of grass swales for improving

water quality from highway runoff.’, Water

research, 46(20), pp. 6731–42.

(14) Forest Research (no date) Improving Air Quality.

(15) Lehmann, S. (2014) ‘Low carbon districts: Mitigating

the urban heat island with green roof

infrastructure’, City, Culture and Society, 5(1), pp. 1–

8.

http://www.susdrain.org/delivering-suds/using-suds/suds-components/swales-and-conveyance-channels/swales.html



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AMENITY LAWNS

Amenity grassland is usually intensively managed, closely mown grassland found in parks, sports grounds, village

greens or around buildings. It provides a permeable surface and so enables source control and infiltration.

Vegetation can filter and trap sediments.

Benefits Wheel

Landscape context

Shows the contribution of amenity lawns to the provision of ecosystem

services. More detail on the next page.

Grassed areas intercept runoff and allow infiltration while

also slowing flows down. Impermeability of urban areas is

one of the main factors in exacerbating surface water

flooding. The cumulative effect of vegetated areas in

infiltrating runoff can mitigate this, although it has to be

taken into account that waterlogged soils will effectively

be impermeable. Amenity areas are present along

roadsides, under trees, in public open spaces and as

recreation grounds.

Designing amenity areas with surface water in mind can

help maximise the benefits. Slightly depressed areas can

provide attenuation and collect runoff from additional

areas (in effect working similar to detention basins or

swales) and keeping open, vegetated areas alongside

rivers provides a space to safely attenuate floods.


£0.07/m2 – £0.6/m2.

Factors: Instalment of a new lawn may

include stripping down old one. Options

for establishing new grass area are

natural colonisation (minimal cost),

grass seed mixtures and turf. (16)

1,600-2,200£/ha/a (0.02-0.22£/m2/a).

Depends on how it is maintained

(hand/gang mown, frequency). Mowing,

intensity depends on aesthetic

requirements. However, maintenance

costs likely to increase proportionally

with smaller size. (17)

Suitable in all areas, any size, as long as

soil infiltration rates are sufficiently high.

If high footfall is expected or vehicular

access necessary, soil can be structurally

strengthened (increasing cost). Infiltration

rates depend on soil type and intensity of

use. High groundwater levels can slow

infiltration down.

Featu

red

Case

Stu

dy

More Meadows, Birmingham & Black Country

This report investigates the opportunities for amenity grassland in parks and

open spaces to be managed for biodiversity and wildlife. Social benefits arise

from the use of local volunteers and engaging park staff, enhancing social

cohesion and sense of place.

The project showcases the importance of engagement of the local

community and staff and generating understanding of the project objectives

prior to implementation.

More: www.bbcwildlife.org.uk/sites/default/files/grasslands.pdf

Image: BBC

http://www.bbcwildlife.org.uk/sites/default/files/grasslands.pdf

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Health: Access. * Potential for dual use as sports ground or

similar. Amenity lawns should be highly accessible, but design

and maintenance are important factors. (1,10)

Air Quality. * Vegetation and soil can trap air pollutants and

dust. (5)

Surface Water. * Can be very high when runoff is

eliminated, a reduction of up to 99% of runoff compared to

asphalt is possible, reducing peak flows and flow volume. This

may be compromised by high footfall on the area and

subsequent compaction as well as soil type. Once soil

becomes waterlogged, area acts as impermeable surface.

(1,2,3,4,5,9,12,14)

Fluvial Flood. * Strategically placed open green spaces can

act as storage for fluvial flooding. (2)

Water Quality. * Sediment and pollutants can be trapped

and to an extent degraded in the soil. However, fertilisation

and pesticide application can impact water quality negatively.

(2,4,7,12,14)

Habitat Provision. * Invertebrates can find habitat in highly

managed grassed areas, for other animals (e.g. birds) it is likely

the area would have to be less managed (e.g. transformed into

rough grassland). Adding structural diversity can provide

significant benefits. (4,6, 13, 15)

Climate Regulation. * Surface temperatures of grassed

areas are much lower (up to 25dC) than asphalt. Additionally,

carbon can be sequestered (in plants and soil), but

management activities are likely to offset the net carbon

benefits. (4,5,8,19)

Low Flows. * Potential for groundwater recharge. (4,5)


Aesthetics. * Greenspace can improve the visual quality of

urban areas. It is very versatile, but a less interesting feature

than other interventions. (1,2,4)

Cultural Activities. * Potentially important part of cultural

spaces, e.g. village greens. Allows cultural activities like

picnicking, playing golf, etc. Depends on size and accessibility,

although even the view of lawns plays a part in cultural

identity and place making. (4,5,10)

Property Value. * Lawn areas on properties have been

shown to add value to properties, but only when well

maintained. Lawn in public spaces can also increase rental

prices in a neighbourhood. (11)

Flood Damage. * Taking up water from their own area and

surrounding areas can help reduce the risk of flooding and the

extent of flooding on a larger scale.


Noise reduction. soft lawns can decrease noise by 3db,

providing mental and physical health benefits and so

improved wellbeing.

Multifunctional. highly multifunctional area that can easily

be enhanced by other SuDS/GI and does not have any safety

concerns that may come with water bodies.

Health. closely mown grasses have the benefit of less risk of

triggering allergies. The proximity of greenspace is beneficial

on mental and physical health, improving social wellbeing and

saving health related costs. Grass areas are main predictors

for the potential of a greenspace to have restorative effects

(with size of a greenspace being the most important factor),

providing stress relief and an “escape”.

Water quality. Poor maintenance may lead to erosion,

litter. This can lead to a decrease in the visual quality and also

impact the watercourses the area might drain to, by clogging

the soil and increasing pollutant load.

Climate regulation. Dry vegetation can be perceived as

ugly or dangerous. Irrigation to counteract this can decrease

the ability to infiltrate water, but increases the cooling

potential of the area. However, it means a greater demand

on water use and energy. This could to an extent be

mitigated by rainwater harvesting on site.

Social disbenefits. poor maintenance and design can

encourage anti-social behaviour and so have a negative

impact on the surrounding areas.



14

References:

(1) CIRIA. (2014). Demonstrating the multiple benefits

of SuDS - a business case.

(2) Woods Ballard, B., Wilson, S., Udale-Clarke, H.,

Illman, S., Ahsley, R., Kellagher, R. (2015): The

Suds Manual. London: CIRIA.

(3) Armson, D., Stringer, P. and Ennos, A. R. (2013)

‘The effect of street trees and amenity grass on

urban surface water runoff in Manchester, UK’,

Urban Forestry & Urban Greening, 12(3), pp. 282–

286.

(4) Beard, James B, and Robert L. Green. (1994) “The

Role of Turfgrasses in Environmental Protection

and Their Benefits to Humans.” Journal of

Environment Quality 23 (3). American Society of

Agronomy, Crop Science Society of America, and

Soil Science Society of America: 452.

(5) Bolund, Per, and Sven Hunhammar. (1999)

“Ecosystem Services in Urban Areas.” Ecological

Economics 29 (2): 293–301.

(6) Chamberlain, D.E., S. Gough, H. Vaughan, J.A.

Vickery, and G.F. Appleton. (2007) “Determinants

of Bird Species Richness in Public Green Spaces:

Capsule Bird Species Richness Showed Consistent

Positive Correlations with Site Area and Rough

Grass.” Bird Study 54 (1). Taylor & Francis Group:

87–97.

(7) Davis, A. P., Shokouhian, M., Sharma, H. and

Minami, C. (2001) ‘Laboratory study of biological

retention for urban stormwater management.’,

Water environment research : a research publication of

the Water Environment Federation, 73(1), pp. 5–14.

(8) Gill, S.E., M.A. Rahman, J.F. Handley, and A.R.

Ennos. (2013) “Modelling Water Stress to Urban

Amenity Grass in Manchester UK under Climate

Change and Its Potential Impacts in Reducing

Urban Cooling.” Urban Forestry & Urban

Greening 12 (3): 350–58.

(9) Lamond, Jessica E., Carly B. Rose, and Colin A.

Booth. (2015) “Evidence for Improved Urban

Flood Resilience by Sustainable Drainage Retrofit.”

Proceedings of the Institution of Civil Engineers -

Urban Design and Planning, September. Thomas

Telford Ltd.

(10) Nordh, H., Hartig, T., Hagerhall, C. M. and Fry, G.

(2009) ‘Components of small urban parks that

predict the possibility for restoration’, Urban

Forestry & Urban Greening, 8(4), pp. 225–235.

(11) Saphores, Jean-Daniel, and Wei Li. (2012)

“Estimating the Value of Urban Green Areas: A

Hedonic Pricing Analysis of the Single Family

Housing Market in Los Angeles, CA.” Landscape

and Urban Planning 104 (3-4): 373–87.

(12) Yang, Jin-Ling, and Gan-Lin Zhang. (2011) “Water

Infiltration in Urban Soils and Its Effects on the

Quantity and Quality of Runoff.” Journal of Soils

and Sediments 11 (5): 751–61.

(13) http://www.newport.gov.uk/en/Leisure-

Tourism/Countryside--Parks/Wildlife-

walks/Amenity-grassland.aspx

(14) Susdrain (2016):

http://www.susdrain.org/delivering-suds/using-

suds/suds-components/source-control/other-

permeable-surfaces/index.html

(15) Forestry Commission (2016):

http://www.forestry.gov.uk/fr/urgc-7edjsm

(16) Costs:

http://www.thegrassseedstore.co.uk/environmental

/grass-only-meadow/native-meadowgrass.html,

http://www.rolawn.co.uk/turf/rolawn-medallion-

turf?gclid=CNvH5f7OrssCFQcUGwod3v4L-

A#tabDescription, http://www.turfonline.co.uk/

(17) The Woodland Trust (2011) Trees or Turf ?


‘The effect of tree shade and grass on surface and

globe temperatures in an urban area’, Urban


http://www.susdrain.org/files/resources/project_info/ciria_proposal_2904_demonstrating_the_multiple_benefits_of_suds_pjsv5_.pdf

http://www.ciria.org/Resources/Free_publications/SuDS_manual_C753.aspx


http://www.sciencedirect.com/science/article/pii/S1618866713000460



http://www.tandfonline.com/doi/abs/10.1080/00063650709461460


http://www.ncbi.nlm.nih.gov/pubmed/11558302




http://www.icevirtuallibrary.com/doi/full/10.1680/udap.13.00022

http://www.icevirtuallibrary.com/doi/full/10.1680/udap.13.00022




http://link.springer.com/10.1007/s11368-011-0356-1

http://www.newport.gov.uk/en/Leisure-Tourism/Countryside--Parks/Wildlife-walks/Amenity-grassland.aspx



http://www.susdrain.org/delivering-suds/using-suds/suds-components/source-control/other-permeable-surfaces/index.html



http://www.forestry.gov.uk/fr/urgc-7edjsm

http://www.thegrassseedstore.co.uk/environmental/grass-only-meadow/native-meadowgrass.html

http://www.thegrassseedstore.co.uk/environmental/grass-only-meadow/native-meadowgrass.html

http://www.rolawn.co.uk/turf/rolawn-medallion-turf?gclid=CNvH5f7OrssCFQcUGwod3v4L-A



http://www.turfonline.co.uk/

https://www.woodlandtrust.org.uk/mediafile/100083921/trees-or-turf-report.pdf


15

WETLANDS

An urban constructed wetland is a type of blue infrastructure (i.e. consisting of a permanent body of water)

that can provide a range of ecosystem services. They are different from ponds in that they have more shallow

zones in which bottom-rooted vegetation can grow. Wetlands consist of different zones that are either

permanently wet, permanently dry or periodically wet. The periodically wet zone provides room for storing

surplus water in high rainfall events. Release of water can be controlled through structures at the outlet of the

wetland. In permanently wet zones, vegetation acts as a filter slowing and stabilising suspended solids and

adsorbing pollutants. Pollutants are also destroyed by microbial processes or UV radiation.

Benefits Wheel

Landscape context

Shows the contribution of wetlands to the provision of ecosystem services.


Wetlands are best suitable as the last stage of the

treatment process (secondary and tertiary treatment).

They provide infiltration (but only above non-vulnerable

groundwater) to an extent and storage.

To function, a wetland needs a continuous water flow.

Artificial as well as natural wetlands store water and

provide habitat for different species. Wetlands can be

designed to suit various sites and functions, however they

generally need a comparatively big area of land to

function and keep costs low.

They should always be preceded by other treatment

interventions or sediment forebays to ensure aesthetic

and hydrologic benefits, and also to keep costs low.


20-35£/m3 or £15,000-160,000 per

wetland. The exact costs depend on

design, with high land take and planning

costs. (4, 11)

0.1£/m2/a. Removal of litter and

potentually silt/sediment, vegetation

(pruning etc.). Fences, landscape

maintenance. Costs are likely to

decline after the first few years. (4)

Residential, Industrial (Retrofit – if site

conditions make it possible or pocket

wetland) Sufficient base flow needs to be

provided, low infiltration rates of soil.

They are best used to take runoff from

multiple areas after it has undergone

primary/secondary treatment. (5,14, 27)

Featu

red

Case

Stu

dy

The Surgery, Kington, Herefordshire

In this new development, a Health Centre was build using SuDS treatment

to manage surface water. The landscape design involved the creation of

areas of new, chiefly native, planting and grassland as well as a series of

wetlands acting as part of the storm-water management system on the site.

Employees and patients of the Health Centre are able to enjoy the

landscape, including the swales that are located in the staff gardens;

however, the wetland is located below the car park and has a post and rail

fence restricting access.

More: http://www.susdrain.org/case-

studies/case_studies/surgery_kington_herefordshire.html

http://www.susdrain.org/case-studies/case_studies/surgery_kington_herefordshire.html

http://www.susdrain.org/case-studies/case_studies/surgery_kington_herefordshire.html

16


Health: Access. * Can provide highly valuable recreational

areas (has been shown to be up to ~63,400£/ha/a) that

encourage physical activity and have positive health impacts.

(17,22, 31)

Air Quality. * Potential to reduce air pollution significantly,

but few studies on constructed wetlands. (8)

Surface Water. * Reduction of volume and peak flow

potential >80%. Storage area needs to be provided (high land

take). Helps to reduce flood impact by delaying high flows but

not necessarily reduction in volume. Varying success. Can

increase peak flow due to saturation if capacity full.

(5,6,7,9,11,14,22, 23, 28)

Fluvial Flood. * Can provide flood prevention if positioned

upstream/in floodplain areas. Few studies on constructed

wetlands. (23, 25)

Water Quality. * Effective pollutant reduction: sediment

~90%, nutrients avg. 60% depending on retention time and

season. Reduction of hyrdocarbons 50-80%, heavy metals

varying but up to 99%. During dry seasons, storm events can

wash out pollution w sediment. High water temperature may

be an issue. (2,5,6,9,11,13,14,18, 26, 32)

Habitat Provision. * Potentially very high but depends on

design. Can provide important stepping stones for migratory

birds, but depends on size. However, high pollutant loads can

compromise this. (18, 19, 22, 24)

Climate Regulation. * High carbon storage potential (up to

2.4kg/m2/yr net), can regulate air temperature and have

significant positive effect on UHI. Dense vegetation increases

carbon sequestration potential. However, GHG release can

potentially occur. (12,16,21,22)

Low Flows. * Wetlands can increase water flow during dry

seasons but may also decrease it. (25)


Aesthetics. * Potentially very high if open water is visible.

Water bodies have been shown to provide sense of place,

restorative environments and so many cultural benefits.

(17,22, 30, 31)

Cultural Activities. * Potential very high, can be used for

angling, birdwatching etc, but depends on design. (17,22, 29)

Property Value. * Can increase property value by up to

28%. Some studies even show up to 300% increase. Increased

spending in commercial areas. (11,20)





Mental health – Blue spaces have high impacts on stress

levels, and emotional connection to blue spaces is higher than

to green spaces. This can strengthen the sense of place and

identity and so improve wellbeing.

Educational value – wetlands can provide highly

biodiverse, unique habitats and if designed and maintained

correctly can be used to educate children and adults about

various nature-related topics. The spaces can also be used as

outdoor classrooms.

Water re-use – Water stored in wetlands can potentially

be re-used for other purposes, e.g. irrigation. This may save

energy and water costs.

Pollution - Danger of pollutants being washed out of

wetland, higher water temperatures in water body can have

impact on aquatic species downstream

Safety – if not designed correctly, it can be perceived as a

hazard mainly for children.

Aesthetic/Amenity – maintenance needs to be carried out

to prevent the wetland from developing odours and

accumulating litter and so becoming an eyesore and

unwelcoming place.

Habitat – if not enough pre-treatment is provided, pollution

of sediments might occur and wildlife might be negatively

impacted by the heavy metals etc in the water.



17

References:




(2) Brown, R. G. (1984) “Effects of an Urban Wetland

on Sediment and Nutrient Loads in Runoff.”

Wetlands 4 (1): 147–58.

(3) de Klein, Jeroen J.M., and Adrie K. van der Werf.

(2014) “Balancing Carbon Sequestration and GHG

Emissions in a Constructed Wetland.” Ecological

Engineering 66 (May): 36–42.





Woods Ballard, B. (2015) The SUDS manual,

CIRIA. London.




(7) Lawrence, A. I., Marsalek, J., Ellis, J. B. and

Urbonas, B. (1996) ‘Stormwater detention &

BMPs’, Journal of Hydraulic Research. Taylor &

Francis Group, 34(6), pp. 799–813


(9) J B Ellis, R B E Shutes and M D Revitt (2003)


Drainage Systems.

(10) Malaviya, Piyush, and Asha Singh. (2016)

“Constructed Wetlands for Management of Urban

Stormwater Runoff Constructed Wetlands for

Management of Urban Stormwater Runoff”

(11) CIRIA (2014) ‘Demonstrating the multiple benefits

of SuDS - a business case’

(12) Charlesworth, S. M. (2010) ‘A review of the

adaptation and mitigation of global climate change

using sustainable drainage in cities’, Journal of

Water and Climate Change. IWA Publishing, 1(3),

p. 165.

(13) Charlesworth, S. M., Harker, E. and Rickard, S.

(2003) ‘A Review of Sustainable Drainage Systems

(SuDS): A Soft Option for Hard Drainage

Questions?’, Geography, 88(2), pp. 99–107.

(14) Ellis, J. B., R. B. E. Shutes, and D. M. Revitt. (2003)

“Guidance Manual for Constructed Wetlands.”

(15) Fleming-Singer, Maia S., and Alexander J. Horne.

(2006) “Balancing Wildlife Needs and Nitrate

Removal in Constructed Wetlands: The Case of

the Irvine Ranch Water District’s San Joaquin

Wildlife Sanctuary.” Ecological Engineering 26 (2):

147–66.

(16) Forestry Commission (2013) Air temperature

regulation by urban trees and green infrastructure.

Farnham.

(17) Ghermandi, Andrea, and Edna Fichtman. (2015)

“Cultural Ecosystem Services of Multifunctional

Constructed Treatment Wetlands and Waste

Stabilization Ponds: Time to Enter the

Mainstream?” Ecological Engineering 84

(November): 615–23.

(18) Helfield, James Mark, and Miriam L. Diamond.

(1997) “Use of Constructed Wetlands for Urban

Stream Restoration: A Critical Analysis.”

Environmental Management 21 (3): 329–41.

(19) Hsu, Chorng-Bin, Hwey-Lian Hsieh, Lei Yang,

Sheng-Hai Wu, Jui-Sheng Chang, Shu-Chuan Hsiao,

Hui-Chen Su, Chao-Hsien Yeh, Yi-Shen Ho, and

Hsing-Juh Lin. (2011) “Biodiversity of Constructed

Wetlands for Wastewater Treatment.” Ecological

Engineering 37 (10): 1533–45.

(20) International Association of Certified Home

Inspectors, Inc. (InterNACHI) (2016): Constructed

Wetlands: The Economic Benefits of Runoff

Controls.

(21) Kayranli, Birol, Miklas Scholz, Atif Mustafa, and Åsa

Hedmark. (2009) “Carbon Storage and Fluxes

within Freshwater Wetlands: A Critical Review.”

Wetlands 30 (1): 111–24.

(22) Moore, T. L. C. and Hunt, W. F. (2012)

‘Ecosystem service provision by stormwater

wetlands and ponds - a means for evaluation?’,

Water research, 46(20), pp. 6811–23.

(23) Persson, J., Somes, N. L. G. and Wong, T. H. F.

(1999) ‘Hydraulics Efficiency of Constructed

Wetlands and Ponds’, Water Science and

Technology. IWA Publishing, 40(3), pp. 291–300.

(24) Semeraro, Teodoro, Cosimo Giannuzzi, Leonardo

Beccarisi, Roberta Aretano, Antonella De Marco,

M. Rita Pasimeni, Giovanni Zurlini, and Irene

Petrosillo. (2015) “A Constructed Treatment

Wetland as an Opportunity to Enhance

Biodiversity and Ecosystem Services.” Ecological

Engineering 82 (September): 517–26.

(25) Shutes, B, M Revitt, and L Scholes. (2009)

“Constructed Wetlands for Flood Prevention and

Water Reuse.”

(26) Shutes, R.B.E. (2001) “Artificial Wetlands and

Water Quality Improvement.” Environment

International 26 (5-6): 441–47.

(27) U.S. Environmental Protection Agency (2009)

Stormwater Wet Pond and Wetland Management

Guidebook.

(28) Villarreal, E. L., Semadeni-Davies, A. and

Bengtsson, L. (2004) ‘Inner city stormwater

http://www.fwr.org/greeninf.pdf


http://link.springer.com/10.1007/BF03160493


https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/411509/Cost_estimation_for_SUDS.pdf




http://www.susdrain.org/files/resources/evidence/suds_lit_review_04.pdf

http://www.tandfonline.com/doi/pdf/10.1080/00221689609498452?instName=University+of+Edinburgh


http://www.forestry.gov.uk/pdf/urgp_evidence_note_006_Improving_air_quality.pdf/$FILE/urgp_evidence_note_006_Improving_air_quality.pdf

https://www.gov.uk/government/publications/constructed-wetlands-and-links-with-sustainable-drainage-systems

http://www.tandfonline.com/doi/abs/10.1080/10643389.2011.574107


http://jwcc.iwaponline.com/content/1/3/165.abstract

http://www.jstor.org/stable/40573828?seq=1#page_scan_tab_contents

https://eprints.mdx.ac.uk/6077/1/P2-159-TR2-e-p.pdf


http://www.forestry.gov.uk/pdf/FCRN012.pdf/$FILE/FCRN012.pdf


http://link.springer.com/10.1007/s002679900033





https://www.nachi.org/constructedwetlands.htm




http://www.sciencedirect.com/science/article/pii/S004313541100710X

http://wst.iwaponline.com/content/40/3/291.abstract





http://www.switchtraining.eu/fileadmin/template/projects/switch_training/files/Resources/Shutes_2010_Constructed_wetlands_for_flood_prevention_and_water_reuse.pdf


http://www3.epa.gov/npdes/pubs/pondmgmtguide.pdf



18

control using a combination of best management

practices’, Ecological Engineering, 22(4-5), pp. 279–

298.

(29) Völker, S. and Kistemann, T. (2013) ‘“I’m always

entirely happy when I'm here!” Urban blue

enhancing human health and well-being in Cologne

and Düsseldorf, Germany.’, Social science &

medicine (1982), 78, pp. 113–24.

(30) Völker, S. and Kistemann, T. (2015) ‘Developing

the urban blue: Comparative health responses to

blue and green urban open spaces in Germany’,

Health & Place, 35, pp. 196–205.

(31) White, M., Smith, A., Humphryes, K., Pahl, S.,

Snelling, D. and Depledge, M. (2010) ‘Blue space:

The importance of water for preference, affect,

and restorativeness ratings of natural and built

scenes’, Journal of Environmental Psychology,

30(4), pp. 482–493.

(32) Wong, T., Breen, P. and Somes, N. (1999) ‘Ponds

vs Wetlands - Performance Considerations in

Stormwater Quality Management’, in

Comprehensive Stormwater and Aquatic

Ecosystems Management. Auckland, pp. 223–231.





http://www.northinlet.sc.edu/training/media/resources/Ponds%20V%20Wetlands%20SW%20Quality%20Mgmt.pdf

19

TREES

Trees can provide a number of different services that depend on their size, species, and location. Their leaves

can trap air pollutants either through taking them up or through deposition, thus removing them from the

surrounding air. They also intercept rainfall and so slow the rate with which water reaches the ground,

increasing infiltration where permeable surfaces are available and additionally reducing runoff through

evaporation and root uptake. Through their wide variation in shape, size and demands they are very versatile

and can be used in multiple settings. Trees are generally perceived as aesthetically pleasing additions to the

landscape and thus provide many less tangible benefits that increase quality of life considerably.

Benefits Wheel

Landscape context

Shows the contribution of trees to the provision of ecosystem services.


Studies have shown that trees can reduce runoff by 62%

compared to the same area of naked asphalt, and a 5%

increase in tree cover in an area can reduce total runoff

by 2%.

Trees act as interception and source control, reducing

the runoff generated on a local scale. Water that is not

intercepted can infiltrate into the tree pit and be led into

storage structures or further treatment. To provide a

comprehensive treatment and management of surface

water, trees should be seen within the wider landscape.

While they are able to intercept rainfall before it

becomes runoff, it is important to understand that their

ability to take up existing runoff and infiltrate it is limited

and they should be complemented with additional

interventions.


£15-400 per singular tree (including

planting costs). Relative costs decrease

with increasing number of trees (potent.

below this).

Dependent on: Species and age of the

tree, location of planting.

0.1£/m2 for managed woodland in

managed greenspace. Higher for

singular trees. (31,32)

Main costs: Pruning Maintenance will

be lower the better the tree is suited

to the conditions – e.g. soil type, water

supply, size of tree pit

Interception and infiltration components

for small area, can be combined with

similar types of SuDS or stand alone. An

open tree pit helps water and oxygen

supply. Soil compaction should be

avoided. (33,34)

Featu

red

Case

Stu

dy

Benefits of Trees in the Victoria BID, London

Existing trees, green spaces and other green infrastructure assets in Victoria

divert up to 112,400 cubic metres of storm water runoffs away from the

local sewer systems every year. This is worth between an estimated

£20,638 and £29,006 in reduced CO2 emissions and energy savings every

year.

The total structural value of all trees in Victoria, (which does not constitute

a benefit provided by the trees, but rather a replacement cost) currently

stands at £2,103,276. The trees in Victoria remove a total of 1.2 tonnes of

pollutants each year and store 847.08 tonnes of carbon.

More:

https://www.itreetools.org/resources/reports/VictoriaUK_BID_iTree.pdf


20


Health: Access. * While trees are not themselves

‘accessible’, they make areas more attractive. Streets with

trees have 20% higher bicycle traffic than those without (26).

Parks with a number of trees are used more than those

without, however dense tree stands can increase fear of

crime.(1,2,3,4,5,6,8,9,7)

Air Quality. * A single tree can reduce PM concentration by

15-20%. Street trees reduce prevalence of asthma in children

and death rates from respiratory diseases. (9,16,30)

Surface Water. * 10-15% of rainfall are intercepted by

canopies (2,000-3,000 litres per year, according to US studies

(15)). Open tree pits increase infiltration, with leaf litter

acting like a sponge, and so reduces runoff even further (up

to 62% reduction of total rainfall volume on area, compared

to 10-20% for asphalt). In severely compacted soils, tree

roots can improve infiltration by 153%. (13,14,28, 29,33,37)

Fluvial Flood. * Trees along river banks (i.e. in the riparian

zone) can act to slow water flow and reduce fluvial flooding.

Water Quality. * By allowing increased infiltration, trees

improve water quality. Leaf litter on the ground reduces soil

erosion, trees intercept pollutants and infiltrate them.

(27,28,37)

Habitat Provision. * Depends on location, size and species

of tree, but can provide important corridors. Especially large

trees are of high importance for biodiversity. Preservation of

trees in developments and preservation of especially larger

areas of existing woodland can have a high impact on urban

biodiversity.) (22,23,24)

Climate Regulation. * Reduce air temperature/UHI

(increasing green cover by 10% reduces temperatures by 3

degrees, areas under canopies can be 1-10 degrees cooler

than open areas). iTree studies in the UK have estimated

annual C sequestration to be 3.65 – 7.4kg/tree. (19,20,21)

Low Flows. * Infiltration allows groundwater recharge or

releases water slowly into the water bodies. This can mean a

positive impact on low flows.


Aesthetics. * Aesthetic benefits have been proven multiple

times, impact on mental health (people feel more relaxed in

areas with trees), place shaping. (7,12,37)

Cultural Activities. * Trees can be important cultural

assets and facilitate some cultural activities. This is dependent

on their context – for example, old trees that are part of

village greens may have different cultural meanings than newly

planted street trees. (12)

Property Value. * Trees in the surrounding environment can

lead to a 5-10% increase in property value, and increase

spending in business areas making areas more attractive to

businesses. (10,11,37)

Flood Damage.* Due to their impact on surface water

flooding, trees can influence the extent of a flood – however,

singular trees are unable to make a big impact and can only

contribute little to fluvial flooding.


(Mental) Health. Urban parks with trees reduce stress

levels more than those without. Trees have positive impacts

on exercise regularity. They have also been connected to

positive impacts on health of new-borns/maternal health.

Energy Savings. Strategically placed trees can reduce

cooling/heating costs in buildings and save energy (10%

savings on energy costs due to cooling). Shelterbelts can

reduce heating costs by up to 18%

Noise Reduction. Trees can act as buffers against noise and

placed strategically minimise the impact of highly used roads.

Property Value. Potential negative impact on properties

(shading, roots, litter), unhealthy trees can pose safety risk.

Trees can also obscure views, leading to less aesthetic value

and in some cases even higher perceptions of unsafety.

Climate Regulation. Release of VOC can have negative

impacts on GHG emissions, as can fuel-intense maintenance.

It is therefore important to select the right species and keep

maintenance as low carbon as possible.

Health. Allergy attacks due to pollen are possible and some

trees can produce VOCs and increase ozone generation.

Selection of species is important as well as their placing in the

urban landscape to avoid trapping of pollutants.



21

References:

Access





In densifying cities, small green spaces such as pocket

parks are likely to become more important as settings

for restoration. The variables most predictive of the

likelihood of restoration were the percentage of ground

surface covered by grass, the amount of trees and

bushes visible from the given viewing point, and

apparent park size.

(2) Commission for Architecture and the Built

Environment (2005) ‘Decent parks? Decent

behaviour?: The link between the quality of parks

and user behaviour Contents Foreword’, pp. 1–

17.

This publication provides practical suggestions for

improving public spaces in ways that can help reduce

vandalism and other anti-social behaviour. It is

informed by research commissioned by CABE Space in

2004. The research, carried out by GreenSpace,

involved over twenty local authorities and seventy-five

community representatives concerned with green

spaces.

Health, Wellbeing and Cultural Benefits

(3) Alcock, I., White, M. P., Wheeler, B. W., Fleming,

L. E. and Depledge, M. H. (2014) ‘Longitudinal

effects on mental health of moving to greener and

less green urban areas.’, Environmental science &

technology. American Chemical Society, 48(2), pp.

1247–55.

This study used panel data to explore three different

hypotheses about how moving to greener or less green

areas may affect mental health over time. Moving to

greener urban areas was associated with sustained

mental health improvements, suggesting that

environmental policies to increase urban green space

may have sustainable public health benefits.

(4) Donovan, G. H., Butry, D. T., Michael, Y.

L., Prestemon, J. P., Liebhold, A. M., Gatziolis, D.

and Mao, M. Y. (2013) ‘The relationship between

trees and human health: evidence from the spread

of the emerald ash borer.’, American journal of

preventive medicine, 44(2), pp. 139–45

Results suggest that loss of trees to the emerald ash

borer increased mortality related to cardiovascular and

lower-respiratory-tract illness. This finding adds to the

growing evidence that the natural environment

provides major public health benefits.

(5) Donovan, G. H., Michael, Y. L., Butry, D. T.,

Sullivan, A. D. and Chase, J. M. (2011) ‘Urban trees

and the risk of poor birth outcomes’, Health and

Place, 17(1), pp. 390–393.

This paper investigated whether greater tree-canopy

cover is associated with reduced risk of poor birth

outcomes in Portland, Oregon. We found that a 10%

increase in tree-canopy cover within 50. m of a house

reduced the number of small for gestational age births

by 1.42 per 1000 births (95% CI-0.11-2.72). Results

suggest that the natural environment may affect

pregnancy outcomes and should be evaluated in future

research.

(6) Lovasi, G. S., Quinn, J. W., Neckerman, K.

M., Perzanowski, M. S. and Rundle, A. (2008)

‘Children living in areas with more street trees

have lower prevalence of asthma.’, Journal of

epidemiology and community health, 62(7), pp.

647–9.

Street trees were associated with a lower prevalence of

early childhood asthma. This study does not permit

inference that trees are causally related to asthma at

the individual level.

(7) Milligan, C. and Bingley, A. (2007) ‘Restorative

places or scary spaces? The impact of woodland

on the mental well-being of young adults.’, Health

& place, 13(4), pp. 799–811.

Engaging with notions of restoration and therapeutic

landscapes literatures, the paper maintains that we

cannot accept uncritically the notion that the natural

environment is therapeutic. Indeed, from this paper it

is clear that a range of influences acts to shape young

people's relationship with woodland environments, but

not all of these influences do so in positive ways.

(8) University of Washington (2012) ‘Crime and Public

Safety. How Trees and Vegetation Relate to

Aggression and Violence.’ 1 of 13.

(9) Faculty of Public Health (2010) ‘Great Outdoors :

How Our Natural Health Service Uses Green

Space To Improve Wellbeing’, pp. 1–8.

(10) Luttik, J. (2000) ‘The value of trees, water and

open space as reflected by house prices in the

Netherlands’, Landscape and Urban Planning, 48(3-

4), pp. 161–167.

This study found the largest increases in house prices

due to environmental factors (up to 28%) for houses

with a garden facing water, which is connected to a

sizeable lake. We were also able to demonstrate that

a pleasant view can lead to a considerable increase in

house price, particularly if the house overlooks water

(8–10%) or open space (6–12%). In addition, the

analysis revealed that house price varies by landscape

type. Attractive landscape types were shown to attract

a premium of 5–12% over less attractive

environmental settings.

(11) Saphores, J.-D. and Li, W. (2012) ‘Estimating the

value of urban green areas: A hedonic pricing

analysis of the single family housing market in Los



http://www.cabespace.org.uk/


http://dx.doi.org/10.1021/es403688w

http://dx.doi.org/10.1021/es403688w






http://jech.bmj.com/content/early/2008/05/01/jech.2007.071894.abstract


https://www.researchgate.net/publication/6423465_Resorative_places_or_scary_spaces_The_impact_of_woodland_on_the_mental_health_of_young_adults

https://depts.washington.edu/hhwb/datasheets/GCGH_datasheet.Crime.pdf

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjy8vjv64bMAhVCXBQKHTzvCQYQFggdMAA&url=http%3A%2F%2Fwww.fph.org.uk%2Fuploads%2Fbs_great_outdoors.pdf&usg=AFQjCNFuzYRUJv3UGyaY73XMuySKgOINpg&sig2=JJBz4m8QOayFYuf7kK6JjQ



22

Angeles, CA’, Landscape and Urban Planning, 104(3-

4), pp. 373–387.

This study analyses 20,660 transactions of single

family detached houses sold in 2003 and 2004 in the

city of Los Angeles, CA, to estimate the value of urban

trees, irrigated grass, and non-irrigated grass areas.

(12) Tabbush, P (2010) ‘Cultural Values of

Trees, Woods and Forests’ Forest Research.

This report presents the results of a literature review

and primary research into the importance of the

cultural values of trees, woods and forests for

sustainable forest management (SFM). The concept of

‘cultural capital’ emerged as helpful in distinguishing

between the values and norms that

stakeholders (including visitors and local communities)

bring to woodlands (‘embodied cultural capital’), and

physical attributes of the woodlands that are of cultural

value (‘objectified cultural capital’, or ‘assets’).

Surface Water Management





286.

This study assessed the impact of trees upon urban

surface water runoff by measuring the runoff from 9

m2 plots covered by grass, asphalt, and asphalt with a

tree planted in the centre. It was found that, while

grass almost totally eliminated surface runoff, trees

and their associated tree pits, reduced runoff from

asphalt by as much as 62%. The reduction was more

than interception alone could have produced, and

relative to the canopy area was much more than

estimated by many previous studies.

(14) Davies, H. and Doick, K. (2015) ‘Valuing the

carbon sequestration and rainwater interception

ecosystem services provided by Britain’s urban

trees.’ Bonn.

(15) Seitz, J. and Escobedo, F. (2014) ‘Urban Forests

in Florida : Trees Control Stormwater Runoff and

Improve Water Quality’. University of Florida.

Neighbourhoods with fewer trees have the potential for

increased stormwater, pollutants, and chemicals

flowing into their water supply and systems, resulting in

health risks, flood damage, and increased taxpayers’

dollars to treat the water. In Santa Monica, CA, rainfall

interception was measured for 29,229 street and park

trees. Researchers found that the trees intercepted

1.6% of total precipitation over a year, providing an

estimated value of $110,890 ($3.80 per tree) saved

on avoided stormwater costs.

Air quality


Climate Regulation





The results from this study show that both grass and

trees can effectively cool surfaces and so can provide

regional cooling, helping reduce the urban heat island

in hot weather. In contrast grass has little effect upon

local air or globe temperatures, so should have little

effect on human comfort, whereas tree shade can

provide effective local cooling.

(18) Davies, H. and Doick, K. (2015) ‘Valuing the

carbon sequestration and rainwater interception

ecosystem services provided by Britain’s urban

trees.’ Bonn.

(19) Forestry Commission (2013) Air temperature

regulation by urban trees and green infrastructure.

Farnham.

Vegetation has a key role to play in contributing to the

overall temperature regulation of cities. Informed

selection and strategic placement of trees and green

infrastructure can reduce the UHI and cool the air by

between 2ºC and 8ºC, reducing heat-related stress and

premature human deaths during high-temperature

events.

(20) Nowak, D. J., Greenfield, E. J., Hoehn, R. E.

and Lapoint, E. (2013) ‘Carbon storage and

sequestration by trees in urban and community

areas of the United States’, Environmental

Pollution, (178), pp. 229–236.

Urban whole tree carbon storage densities average

7.69 kg C m2 of tree cover and sequestration densities

average 0.28 kg C m2 of tree cover per year. Total

tree carbon storage in U.S. urban areas (c. 2005) is

estimated at 643 million tonnes ($50.5 billion value;

95% CI ¼ 597 million and 690 million tonnes) and

annual sequestration is estimated at 25.6 million

tonnes ($2.0 billion value; 95% CI ¼ 23.7 million to

27.4 million tonnes).

(21) Lehmann, S. (2014) ‘Low carbon districts:

Mitigating the urban heat island with green roof

infrastructure’, City, Culture and Society, 5(1), pp. 1–

8. doi: 10.1016/j.ccs.2014.02.002.

The integration of trees, shrubs and flora into green

spaces and gardens in the city is particularly important

in helping to keep the urban built environment cool,

because buildings and pavements increase heat

absorption and reflection (what is called the urban

heat island effect). Integrated urban development with

a focus on energy, water, greenery and the urban

microclimate will have to assume a lead role and

urban designers will engage with policy makers in

order to drastically reduce our cities’ consumption of

energy and resources. This paper introduces the

holistic concept of green urbanism as a framework for

environmentally conscious urban development.

Habitat Provision

(22) Alvey, A. A. (2006) ‘Promoting and preserving

biodiversity in the urban forest’, Urban Forestry &

Urban Greening, 5(4), pp. 195–201.

The potential for urban areas to harbor considerable

amounts of biodiversity needs to be recognized by city

planners and urban foresters so that management

practices that preserve and promote that diversity can

be pursued. Management options should focus on

http://www.forestry.gov.uk/pdf/Cultural_value_woods_full_report_March2010.pdf/$FILE/Cultural_value_woods_full_report_March2010.pdf


https://www.bfn.de/fileadmin/BfN/klimawandel/Dokumente/ECBCC2015/2015-11-18/Session8/Davies_-_Valuing_the_C_seq_and_rainwater.pdf

https://edis.ifas.ufl.edu/fr239



https://www.bfn.de/fileadmin/BfN/klimawandel/Dokumente/ECBCC2015/2015-11-18/Session8/Davies_-_Valuing_the_C_seq_and_rainwater.pdf


https://www.itreetools.org/eco/resources/nrs_2013_nowak_001.pdf

https://www.itreetools.org/eco/resources/nrs_2013_nowak_001.pdf



23

increasing biodiversity in all aspects of the urban forest,

from street trees to urban parks and woodlots.

(23) Mörtberg, U. and Wallentinus, H.-G. (2000) ‘Red-

listed forest bird species in an urban environment

— assessment of green space corridors’,

Landscape and Urban Planning, 50(4), pp. 215–

226.

The logistic regression models showed that important

properties of remnants of natural vegetation were

large areas of forest on rich soils, together with

connectivity in the form of amounts of this habitat in

the landscape. These properties were associated with

the green space corridors. Implications for the design

of urban green space corridors would be to treat

mature and decaying trees and patches of moist

deciduous forest as a resource for vulnerable species,

and to conserve large areas of natural vegetation

together with a network of important habitats in the

whole landscape, in this case forest on rich soils, also in

built-up areas.

(24) Stagoll, K., Lindenmayer, D. B., Knight, E., Fischer,

J. and Manning, A. D. (2012) ‘Large trees are

keystone structures in urban parks’, Conservation

Letters, 5(2), pp. 115–122.

This study found that (1) large trees had a consistent,

strong, and positive relationship with five measures of

bird diversity, and (2) as trees became larger in size,

their positive effect on bird diversity increased. Large

urban trees are therefore keystone structures that

provide crucial habitat resources for wildlife. Hence, it

is vital that they are managed appropriately. With

evidence-based tree preservation policies that

recognize biodiversity values, and proactive planning

for future large trees, the protection and perpetuation

of these important keystone structures can be

achieved.

General/broader References (for multiple

benefits)

(25) Bird, W. (2007) ‘Natural Thinking’, Royal Society

for the Protection of Birds, pp. 1–116.

(26) McPherson, E. G., Simpson, J. R., Peper, P. J.,

Gardner, S. L., Vargas, K. E. and Xiao, Q. (2007)

Northeast Community Tree Guide.

Presents benefits and costs for representative small,

medium, and large deciduous trees and coniferous

trees in the Northeast region derived from models

based on indepth research carried out in the borough

of Queens, New York City. Average annual net benefits

(benefits minus costs) increase with mature tree size

and differ based on location: $5 (yard) to $9 (public)

for a small tree, $36 (yard) to $52 (public) for a

medium tree, $85 (yard) to $113 (public) for a large

tree, $21 (yard) to $33 (public) for a conifer.

(27) Roy, S., Byrne, J. and Pickering, C. (2012) ‘A

systematic quantitative review of urban tree

benefits, costs, and assessment methods across

cities in different climatic zones’, Urban Forestry &

Urban Greening, 11(4), pp. 351–363.

Urban trees can potentially mitigate environmental

degradation accompanying rapid urbanisation via a

range of tree benefits and services. But uncertainty

exists about the extent of tree benefits and services

because urban trees also impose costs (e.g. asthma)

and may create hazards (e.g. windthrow). Few

researchers have systematically assessed how urban

tree benefits and costs vary across different cities,

geographic scales and climates. This paper provides a

quantitative review of 115 original urban tree studies,

examining: (i) research locations, (ii) research methods,

and (iii) assessment techniques for tree services and

disservices.

(28) The Mersey Forest (2014) Urban Catchment

Forestry: The strategic use of urban trees and

woodlands to reduce flooding, improve water

quality, and bring wider benefits.

(29) U.S. Environmental Protection Agency

(2013) Stormwater to Street Trees. Washington,

DC.

(30) Wang, Y., Bakker, F., de Groot, R. and Wörtche,

H. (2014) ‘Effect of ecosystem services provided

by urban green infrastructure on indoor

environment: A literature review’, Building and

Environment, 77, pp. 88–100.

The economic effects of adjoining vegetation and green

roofs on climate regulation provided energy savings of

up to almost $250/tree/year, while the air quality

regulation was valued between $0.12 and $0.6/m2

tree cover/year. Maximum monetary values attributed

to noise regulation and aesthetic appreciation of urban

green were $20 – $25/person/year, respectively. Of

course these values are extremely time- and context-

dependent but do give an indication of the potential

economic effects of investing in urban green

infrastructure.

Guidance

(31) The Woodland Trust (2002) ‘Urban woodland

management guide 4: Tree planting and woodland

creation.’

(32) The Woodland Trust (2011) Trees or Turf ?

The costs of woodland in managed green space are

£1,500/ha/a for the first 4 years after establishment,

after which they become a cheaper alternative to

amenity grassland, reducing annual maintenance costs

per hectare to £630.

(33) The Woodland Trust (2015) ‘Practical Guidance:

Residential Developments and Trees’.

Planting trees can slow the flow of water and reduce

surface water runoff by up to 62 per cent compared to

asphalt. A single young tree planted in a small pit over

an impermeable asphalt surface can reduce runoff by

around 60 per cent, even during the winter when it is

not in leaf. Tree roots can increase infiltration rates in

compacted soils by 63 per cent, and in severely

compacted soils by 153 per cent. A single tree has

been estimated to reduce PM concentration by 15-20

per cent. Natural England has estimated that access to

quality green space could save around £2.1 billion in

health care costs. The presence of trees is perceived as

indicating a more cared for neighbourhood and the


http://doi.wiley.com/10.1111/j.1755-263X.2011.00216.x


https://www.rspb.org.uk/Images/naturalthinking_tcm9-161856.pdf

https://www.itreetools.org/streets/resources/Streets_CTG/PSW_GTR202_Northeast_CTG.pdf

https://www.itreetools.org/streets/resources/Streets_CTG/PSW_GTR202_Northeast_CTG.pdf


http://www.merseyforest.org.uk/files/documents/1310/Urban%20Catchment%20Forestry%20prospectus%20-%20final%20-%20Oct%202014.pdf

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwia-5SC54bMAhXGOhQKHUqtAlMQFgg7MAQ&url=https%3A%2F%2Fwww.epa.gov%2Fsites%2Fproduction%2Ffiles%2F2015-11%2Fdocuments%2Fstormwater2streettrees.pdf&usg=AFQjCNFXIFXkWPYe14NsVtS7KLu6Hd0YuA&sig2=uR_ShZug7lx40k-AtcyILw

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwia-5SC54bMAhXGOhQKHUqtAlMQFgg7MAQ&url=https%3A%2F%2Fwww.epa.gov%2Fsites%2Fproduction%2Ffiles%2F2015-11%2Fdocuments%2Fstormwater2streettrees.pdf&usg=AFQjCNFXIFXkWPYe14NsVtS7KLu6Hd0YuA&sig2=uR_ShZug7lx40k-AtcyILw



http://visitwoods.org.uk/SiteCollectionDocuments/pdf/urbanwoodlandguide4.pdf

https://www.woodlandtrust.org.uk/mediafile/100083921/trees-or-turf-report.pdf

http://www.woodlandtrust.org.uk/publications/2015/07/residential-developments-and-trees/

24

presence of street trees was associated with a

decreased incidence of crime.

(34) Sustrans (no date): Introducing plants and trees

into your street.

(35) Forestry Commission (2009) ‘The London Trees

and Woodlands Standard Costs .’

(36) Trees for Cities:

http://www.treesforcities.org/about-

us/information-resources/benefits-of-urban-trees/

(37) Warwick District Council (2003) ‘The Benefits of

Urban Trees. A summary of the benefits of urban

trees accompanied by a selection of research

papers and pamphlets.’

This briefing note is an attempt to summarise some of

the benefits of urban trees. A number of papers

relevant to the subject of the benefits of urban trees

have, with the kind permission of their authors, been

included in the appendices.

http://www.sustrans.org.uk/sites/default/files/images/files/migrated-pdfs/Section%2011.%20Introducing%20plants%20and%20trees%20into%20your%20street.pdf

http://www.forestry.gov.uk/forestry/infd-7rrdf3

http://www.treesforcities.org/about-us/information-resources/benefits-of-urban-trees/

http://www.treesforcities.org/about-us/information-resources/benefits-of-urban-trees/

http://www.naturewithin.info/UF/TreeBenefitsUK.pdf

25

RETENTION PONDS/BASINS

Retention ponds are a type of green/blue infrastructure that feature a permanently wet area of water (i.e.

ponds), designed to store water and provide attenuation and treatment, supporting aquatic and emergent

vegetation. They empty into a receiving water body. Retention ponds work similar to wetlands but can store

more water. Phytoplankton in the water body absorbs soluble pollutants, and sedimentation removes solids

from the water column.

Benefits Wheel

Landscape context

Shows the contribution of retention ponds to the provision of ecosystem


Ponds provide infiltration and storage, and are most

effectively used lower in the ‘catchment’, after water

reaching the pond has already gone through pre-

treatment. They can, however, provide primary,

secondary and tertiary treatment. The retention time of

permanent water is linked to the effectiveness of

pollutant treatment, and the volume of the storage area

to its capacity for holding floods.

The intended catchment area should therefore be taken

into account when calculating the storage volume of a

pond. Their appearance is very variable and should be

adapted to the context.


£15-25/m3 treated water (low-

medium). Depends on site context –

sometimes existing natural depressions

can be used. Typically high land take

(>5ha), but can be designed to be

smaller. Long design life (20-50 yrs).

0.5-1£/m2 surface area. Litter and

debris removal, sediment removal may

be required. Vegetation management.

Outlets and inlets need to be kept free.

If sediment is not removed sufficiently

before entering the pond, dredging may

be necessary, reducing design life and

increasing costs.

Commercial and Residential, Retrofit/high

density area unlikely due to high land

take. Liner enables installation above

vulnerable groundwater. If groundwater

table is high, a liner could also improve

sedimentation by preventing constant

inflow into the pond. Continuous water

supply must be given to ensure

permanent pool does not dry out.

Featu

red

Case

Stu

dy

Ardler Village, Dundee

Ardler was originally a Local Authority housing estate built in the late 1960s

with over 3200 flats in six multi-storey buildings housing nearly 8000

people. The area suffered economic decline during the 1980s and studies in

the 1990s showed high numbers of single parent families and long term

unemployment. Dundee City Council bid for funding to prevent irreversible

decline and were awarded £85 million to regenerate the area in 1999.

SuDS were used in the regeneration, including two retention ponds and

swales, alongside copses of mature trees, sports facilities and “pocket

parks” within each neighbourhood.

More:

http://greenspacescotland.org.uk/SharedFiles/Download.aspx?pageid=133&m

id=129&fileid=74

http://greenspacescotland.org.uk/SharedFiles/Download.aspx?pageid=133&mid=129&fileid=74

http://greenspacescotland.org.uk/SharedFiles/Download.aspx?pageid=133&mid=129&fileid=74

26


Health: Access. * Water bodies encourage low intensity

activities and the areas around ponds can be designed to offer

space for recreational activities. (4, 11, 12, 18, 26, 27)

Air Quality. *Plants in the area surrounding the pond as

well as the soil are likely to take up a certain amount of

pollutants. (7)

Surface Water. * Provide peak discharge control for small

and medium storms (10 yr return period) or even large

storms if carefully designed. Performance depends on storage

volume permitted. Volume reduction depends on infiltration

and storage time. (1, 4, 5, 6, 9, 11, 12, 19, 20, 22, 23)

Fluvial Flood. * By storing water and attenuating peak flow,

retention ponds can positively influence the risk of flooding

downstream. (4, 11,22,23)

Water Quality. * Avg sediment removal efficiency of 90%, N

30%, P 50%, metals 50-80%. Depends on the retention time

provided by the pond. (2, 4, 5, 8, 9, 11, 16, 17, 21,27)

Habitat Provision. * Ponds can harbour wildlife and aquatic

vegetation and also function as habitat corridors and stepping

stones for wildlife. They perform an ecologically highly

important function, especially in the urban environment. (4, 12,

18)

Climate Regulation. * Water bodies can balance

temperatures and mitigate the UHI effect. Vegetation can take

up CO2 that can consequently be buried, but Methane and

other GHG can also be released. (10, 14, 18)

Low Flows. * Ponds can potentially release water during dry

periods, and the possibility to re-use water can reduce

pressure on mains water. (4)


Aesthetics. * Ponds are an aesthetically pleasing landscape

feature, providing a sense of beauty and so promoting

wellbeing. (4, 11, 12, 13, 18)

Cultural Activities. * Water bodies have been shown to

provide opportunity for reflection and social interaction and

so are important cultural points if maintained and designed

adequately. Can be used as educational facilities. (4, 11, 13,

24, 25, 26)

Property Value. * Can add significant property value to

development and increase business and tourism. 150%

increase in property value in residential area where view of

the water is available. (4, 11, 13, 18)


removing surface water runoff, retention basins can reduce

severity of surface water floods.


Water re-use. Depending on the water quality, water from

ponds can be reused for watering greenspaces or other non-

potable uses.

Mental Health. Bodies of standing and running water

(excluding marshes/swamps) have been shown to provide

more mental health and aesthetic benefits than built urban

environment without water and even in greenspaces, those

featuring water are ranked as being more interesting and

restorative.

Water quality. Eutrophication in summer. Avoid by

providing constant baseflow, prevent runoff of water directly

from fertilised areas around pond (e.g. lawns). It is important

to provide an initial stage of water treatment (e.g. traps, filter

strips, sediment forebays) before runoff is discharged into

ponds.

Cultural Activities. If all surrounding area managed

intensively, the ecological potential of the intervention sinks.

But, if vegetation is not managed at all, the area may have low

potential for recreational activities.

Habitat. Invasive species can be problematic.

Climate. Waterbodies may emit GHG.



27

References:













CIRIA. London.









(8) Birch, G. F. and Fazelli, M. S. (2006): Efficiency of a

Retention/detention Basin to Remove

contaminants from Urban Stormwater’, Urban

Water Journal, 3.2, 69–77



Drainage Systems.

(10) McPhillips, L. and Walter, T.(2015): Hydrologic

Conditions Drive Denitrification and Greenhouse

Gas Emissions in Stormwater Detention Basins’,

Ecological Engineering, 85 (2015), 67–75

(11) Susdrain (2016):


suds/suds-

components/retention_and_detention/retention_p

onds.html


of SuDS - a business case’

(13) Bastien, N. R. P., Arthur, S. and McLoughlin, M. J.

(2012) ‘Valuing amenity: public perceptions of

sustainable drainage systems ponds’, Water and

Environment Journal, 26(1), pp. 19–29.

(14) Charlesworth, S. M. (2010) ‘A review of the

adaptation and mitigation of global climate change

using sustainable drainage in cities’, Journal of

Water and Climate Change. IWA Publishing, 1(3),

p. 165.

(15) Charlesworth, S. M., Harker, E. and Rickard, S.

(2003) ‘A Review of Sustainable Drainage Systems

(SuDS): A Soft Option for Hard Drainage

Questions?’, Geography, 88(2), pp. 99–107.

(16) Comings, K. J., Booth, D. B. and Horner, R. R.

(2000) ‘Storm Water Pollutant Removal by Two

Wet Ponds in Bellevue, Washington’, Journal of

Environmental Engineering. American Society of

Civil Engineers, 126(4), pp. 321–330.

(17) Heal, K. (2000) SUDS Ponds in Scotland -

Performance Outcomes to Date.

(18) Moore, T. L. C. and Hunt, W. F. (2012)

‘Ecosystem service provision by stormwater

wetlands and ponds - a means for evaluation?’,

Water research, 46(20), pp. 6811–23.

(19) Persson, J., Somes, N. L. G. and Wong, T. H. F.

(1999) ‘Hydraulics Efficiency of Constructed

Wetlands and Ponds’, Water Science and

Technology. IWA Publishing, 40(3), pp. 291–300.

(20) Persson, J. and Wittgren, H. B. (2003) ‘How

hydrological and hydraulic conditions affect

performance of ponds’, Ecological Engineering,

21(4-5), pp. 259–269.

(21) Sniffer (2004) SUDS in Scotland - The Monitoring

Programme.

(22) U.S. Environmental Protection Agency (2009)

Stormwater Wet Pond and Wetland Management

Guidebook.

(23) Villarreal, E. L., Semadeni-Davies, A. and

Bengtsson, L. (2004) ‘Inner city stormwater

control using a combination of best management

practices’, Ecological Engineering, 22(4-5), pp. 279–

298.

(24) Völker, S. and Kistemann, T. (2013) ‘“I’m always



and Düsseldorf, Germany.’, Social science &

medicine (1982), 78, pp. 113–24.

(25) Völker, S. and Kistemann, T. (2015) ‘Developing

the urban blue: Comparative health responses to

blue and green urban open spaces in Germany’,

Health & Place, 35, pp. 196–205.





scenes’, Journal of Environmental Psychology,

30(4), pp. 482–493.

(27) Wong, T., Breen, P. and Somes, N. (1999) ‘Ponds

vs Wetlands - Performance Considerations in

Stormwater Quality Management’, in

Comprehensive Stormwater and Aquatic

Ecosystems Management. Auckland, pp. 223–231.



http://www.crew.ac.uk/sites/www.crew.ac.uk/files/documents/CREW%20Stage1Report_FINAL.pdf













http://doi.wiley.com/10.1111/j.1747-6593.2011.00259.x

http://jwcc.iwaponline.com/content/1/3/165.abstract

http://www.jstor.org/stable/40573828?seq=1#page_scan_tab_contents

http://ascelibrary.org/doi/10.1061/%28ASCE%290733-9372%282000%29126%3A4%28321%29

http://www.geosciences.ed.ac.uk/homes/kheal/conconf.pdf


http://wst.iwaponline.com/content/40/3/291.abstract


http://www.sniffer.org.uk/files/6613/4183/8009/SR0251.pdf

http://www3.epa.gov/npdes/pubs/pondmgmtguide.pdf







http://www.northinlet.sc.edu/training/media/resources/Ponds%20V%20Wetlands%20SW%20Quality%20Mgmt.pdf

28

DETENTION PONDS/BASINS

Detention ponds or basins are usually dry depressions in the ground that can be vegetated or grey. While

usually designed to provide only short term storage of water, their pollutant removal efficiency is higher when

they are designed to hold water for longer (they are then called extended detention basins). They do so by

allowing sediment to settle and biological processes to take place that destroy nutrients and other pollutants.

Benefits Wheel

Landscape context

Shows the contribution of detention ponds to the provision of ecosystem


Detention basins act mainly as storage areas and can

provide treatment of water from a larger catchment area.

Surface water can be stored as part of a routine runoff

path (‘on-line component’) or they can act to capture

overflow when the usual train of treatment is insufficient

(‘off-line’), before it is discharged into the sewer system

or further treatment.

The intended function influences the design, with on-line

components usually being vegetated to provide infiltration

and pollutant treatment capacities. To maintain their

function, pre-treatment – for example sediment forebays

– is necessary.

They can be combined with swales, and including small

ponds or wetlands can increase treatment performance.

In addition, they can provide valuable recreational areas.


15-55£/m3 volume, with a lifetime of up

to 50 years. Costs depend on the site

and context, as well as the scale of the

development. (5)

0.3£/m2/a. Can be part of landscaping.

Inlet and outlet need to be cleaned

regularly and sediment monitored and

removed if necessary. Regular

maintenance is necessary. (5)

Residential, Commercial, Retrofit.

Multiple uses possible and can therefore

be incorporated in existing amenity space

and used for recreation. (6,14,15)

Featu

red

Case

Stu

dy

Lamb Drove, Cambridgeshire

Lamb Drove is a residential development of 35 homes on a one-hectare

site. SuDS was incorporated from the start of development (2004) to prove

that it can be practical in new residential developments, particularly in

Cambridgeshire which is low-lying and has plans for up to 50,000 new

homes by 2016.

A range of SuDS components have been used, including permeable

pavements, green roofs, swales and detention basins. The Management

Train concept was used across the site, this mimics natural drainage as

much as possible and aims to control runoff as close as possible to its

source.

More: Report: http://robertbrayassociates.co.uk/projects/lamb-drove/

http://robertbrayassociates.co.uk/projects/lamb-drove/

29


Health: Access. * Detention basins can be used as

multifunctional areas and so provide opportunities for

recreation and sport. (2,6,14)

Air Quality. * Potentially, pollutants can be adsorbed by

vegetation and soil. (9)

Surface Water. * Detention basins have a high impact on

peak flows and can reduce volume of runoff (20-90%), but are

most effective for small storms. Extended detention basins

can achieve better outcomes. (7, 8, 10, 11)

Fluvial Flood. * Detention basins may influence fluvial floods

downstream by reducing the amount of water discharged into

rivers. (2)

Water Quality. * Especially high sediment removal (40-70%)

but also for metals and insoluble pollutants, but lower for

soluble pollutants. Higher for extended detention basins. (3, 4,

7, 10, 11)

Habitat Provision. * Low potential but planting of native

vegetation and shrubs can improve habitat conditions for

wildlife. Invasive species can be a problem. (6, 13, 15)

Climate Regulation. * DB can reduce the UHI effect and

store carbon if vegetated. Long storage times, while improving

nutrient removal, can increase GHG emissions. (2, 13,16)

Low Flows. * Groundwater recharge is possible. (6,13)


Aesthetics. * Depending on design the aesthetic value can

be significant. In highly urbanised areas where grey design is

required, this can be enhanced to look appealing and

provide multifunctional space. (6,13,15)

Cultural Activities. * Depending on design, detention

basins can provide space for cultural activities. (6, 14, 15)

Property Value. * Good design increases property value in

close vicinity to detention basins. (11)


removing surface water runoff, detention basins can reduce

severity of surface water floods.


No additional benefits Climate Regulation. Depending on the design, NH4 and

CH4 can be emitted, more so when storage times are longer.

This should be considered when designing the basin and

outlet.

Aesthetics. Lack of maintenance can lead to swampy areas

at the outlet of the basin which can be perceived as

dangerous or simply ugly, and can also have an impact on the

multi-functionality of the space.

Water quality. Sediment removal needs to be taken care of

if accumulation of metals happens at the bottom of the basin.

Otherwise, the soil can become contaminated and high

pollution can occur in the outflow of the basin.



30

References:

(1) Ahiablame, L. M., Engel, B. A. and Chaubey, I.

(2012) Effectiveness of Low Impact Development


Future Research.








(4) Deletic, A. (2005) ‘Sediment transport in urban

runoff over grassed areas’, Journal of Hydrology,

301(1-4), pp. 108–122.






CIRIA. London.









(10) Birch, G. F. and Fazelli, M. S. (2006): Efficiency of a

Retention/detention Basin to Remove

contaminants from Urban Stormwater’, Urban

Water Journal, 3.2, 69–77



Drainage Systems.

(12) Lee, J. S. and Li, M. (2009): The Impact of

Detention Basin Design on Residential Property

Value: Case Studies Using GIS in the Hedonic Price

Modeling’, Landscape and Urban Planning, 89.1-2,

7–16

(13) McPhillips, L. and Walter, T.(2015): Hydrologic

Conditions Drive Denitrification and Greenhouse

Gas Emissions in Stormwater Detention Basins’,

Ecological Engineering, 85 (2015), 67–75

(14) Susdrain (2016):


suds/suds-

components/retention_and_detention/Detention_

basins.html


of SuDS - a business case’, (October), p. 45.





https://engineering.purdue.edu/ecohydrology/Pubs/2012%20WASP%20Ahiablame%20et%20al.pdf



http://www.crew.ac.uk/sites/www.crew.ac.uk/files/documents/CREW%20Stage1Report_FINAL.pdf














http://www.susdrain.org/delivering-suds/using-suds/suds-components/retention_and_detention/Detention_basins.html






31

INTENSIVE GREEN ROOFS

Intensive green roofs are a type of green roof with deeper substrate and shrubby vegetation or even trees.

They are usually accessible and can often take the shape of a garden, which also means they require more

maintenance than extensive roofs. They can also include blue roof elements (e.g. rainwater irrigation or water

storage features). Due to their deeper substrate, they put higher loads onto roof structures than extensive

green roofs, however this also means that they have higher capacities to store water.

Benefits Wheel

Landscape context

Shows the contribution of intensive green roofs to the provision of

ecosystem services. More detail on the next page.

Intensive green roofs have the same function as any open,

permeable surface: they provide interception and source

control, and are therefore part of the first stages of

treatment. They effectively reduce the impermeable

surface of an urban area and act to reduce runoff.

They are able to provide storage to an extent, but need

further connection to drainage systems.

Green roofs can be combined with rainwater harvest

systems or feature blue spaces – like ponds – that can use

the collected runoff. As they cannot receive runoff from

adjoining areas, their effect is on a limited scale, but

cumulative effects on a wider area should not be

underestimated.

Additionally, green roofs can improve wellbeing by

reducing air temperature and improving air quality in

urban areas.


£100-140/m2 (high). But can increase

the lifetime of roofing compared to

conventional roofs by up to three times.

May be higher for retrofit. However, no

additional land take is required.

Low to High. Regular inspection

needed. May need irrigation and

drainage systems. Due to the

importance of their appearance,

maintenance similar to that of parks or

gardens can be required.

Domestic, Industrial, Retrofit possible.

Only on flat roofs. Plants should be

carefully selected to minimise irrigation

and fertilisation needs. Intensive green

roofs need strong roof structures due to

their higher weight.

Featu

red

Case

Stu

dy

Bridgewater Green Roofs, Somerset

This report investigates the whole life costs of a living roof (extensive green

roof) in Somerset. It compares costs of an exposed roof, a sedum roof and

a biodiverse roof and finds that the biodiverse roof achieves the best

financial and non-financial results, due to a longer life time and insulation

benefits.

It also attracts the widest range of animals and so has the greatest benefits

for ecology. It also states that added insulation effects of bio diverse and

sedum living roofs will save approximately 4.9t of CO2 per annum or a total

of 245t over the life of the living roof.

More: The Solution Organisation (2005): Whole Life Costs & Living Roofs

– The Springboard Centre, Bridgewater.

http://www.thesolutionorganisation.com/Living%20roof%20Bridgewater%20

003.pdf

Image: greenroofs.com

http://www.thesolutionorganisation.com/Living%20roof%20Bridgewater%20003.pdf


32


Health: Access. * Accessible intensive green roofs can

provide stress relief, space for exercise, and improve mental

health. However, access may be restricted. (4,17)

Air Quality. * IGR provide high potential for removing

pollutants from the air. Studies in Chicago have estimated

removal of 50% O3, 27% NO2 and 7% SO2.Through their

mix of different vegetation types, IGR have the potential to

remove 3x as many pollutants in total compared to those

with only grass. Removal depends on season, species, and

local factors. (13, 15, 16, 19)

Surface Water. * Intensive green roofs are considered to

have an attenuation capacity of 90-100%, capturing 70+% of

rainfall volume and delaying peak flows. (2,4,5,6,7,10,16,24)

Fluvial Flood. * Green roofs are unlikely to contribute to

reducing fluvial flooding.

Water Quality. * Overall, they have a positive impact on

water quality. Pollution reduction can exceed 90% for various

metals and phosphorus up to 64%. First flush effects may

occur. (2,4, 5, 13, 16)

Habitat Provision. * Green roofs can provide important

ecological stepping stones and habitats for invertebrates.

Intensive green roofs face more disturbance through

maintenance and use. Ecological potential can be maximised

through the selection of suitable vegetation. (4,6,11)

Climate Regulation. * The carbon sequestration/storage

potential depends on the vegetation used. Additionally, IGR

regulate air temperature – green surface areas can reduce

temperatures by up to 3 degrees. (1,4,8,9,13)

Low Flows. * IGR could even need irrigation and so increase

demand on water resources.


Aesthetics. * Green roofs can provide the same high

aesthetic benefits as public parks or gardens, however there

is little literature analysing this benefit. (6,23)

Cultural Activities. * Where access is given, these places

can provide settings for social bonding, strengthen

communities and potentially allow cultural activities like

gardening and farming. (6,17)

Property Value. * Studies have mentioned increases in

property value through installation of green roofs but have not

quantified them.

Flood Damage. * By reducing the impermeability of an urban

area, green roofs can help to reduce severity of floods.


Energy saving. Green roofs can reduce temperatures in

buildings (up to 75% reduction in cooling demand shown in

extensive roofs, and higher for intensive). A case study in

Bridgewater, Somerset (see below) estimated a fuel saving of

GBP 5.20/m² per year.

Mental health. Green spaces have positive effects on

physical and mental health that are related to exercise and

the ability to view green/natural areas. Green roofs, can

therefore be a contribution to raising quality of life especially

in highly urbanised areas.

Noise reduction. Green roofs have been shown to reduce

noise. One study has shown a reduction of 8dB.

Education. In highly dense urban environments, accessible

green roofs can provide a safe and convenient outdoor

learning environment that not only gives access to natural

habitats but can also increase focus and wellbeing of

pupils/students.

Aesthetics vs Runoff control – The wish and need to

maintain lush and aesthetically pleasing vegetation can mean

that irrigation and/or fertilisation is necessary during dry

spells. This may decrease the ability to store/absorb

precipitation; increases water consumption and, in the case

of fertilisation, decrease the water quality of the runoff. To

an extent, this can be avoided by coupling water harvesting

systems with green roofs, so that dry periods can be

overcome with water from previous storm events. This also

increases storage capacity of the roof. If designed adequately,

the stored water can even be used to enhance the landscape

by providing aesthetically pleasing water features (blue roof).

*** Indication of confidence. * Literature confirms positive

influence. * Mostly positive results in literature and/or little

literature available. * Varying results in literature, little literature

available

33

References:

(1) Coutts, A.M. et al., 2013. Assessing practical

measures to reduce urban heat: Green and cool

roofs. Building and Environment, 70, pp.266–276.

(2) Czemiel Berndtsson, J., 2010. Green roof

performance towards management of runoff water

quantity and quality: A review. Ecological

Engineering, 36(4), pp.351–360.

A runoff reduction of 27-81% for extensive roofs.

Exact amount depends on rainfall intensity, substrate

and drainage. Runoff water quality varies greatly but

they can contribute significantly to pollutant reduction.

Green roofs can be an effective tool to manage small

storms in urbanised areas, but additional measures

need to be taken for larger storms.



(4) Forest Research, 2010. Benefits of Green

Infrastructure, Farnham: Forest Research.

Extensive green roofs can reduce pollution compared

to convetional roofs. They can reduce runoff by 45%,

and also provide ecological services, being used by

birds and invertebrates.

(5) Glass, C.C., 2007. Green Roof Water Quality and

Quantity Monitoring,




CIRIA. London.

Intensive green roofs require maintenance and are

usually accessible. They provide good contribution to

thermal performance of buildings, as well as good

water retention capacity. Pollution removal is variable.

Can provide great amenity benefits.

(7) Lamera, C. et al., 2013. Green roof impact on the

hydrological cycle components. In EGU 10th

General Assembly. p. 8038.

(8) Lehmann, S., 2014. Low carbon districts: Mitigating


infrastructure. City, Culture and Society, 5(1),

pp.1–8

(9) Liu, K.K.Y. & Baskaran, B., 2003. Thermal

performance of green roofs through field

evaluation, Ottawa.

(10) Mentens, J., Raes, D. & Hermy, M., 2006. Green

roofs as a tool for solving the rainwater runoff

problem in the urbanized 21st century? Landscape

and Urban Planning, 77(3), pp.217–226.

(11) Oberndorfer, E., Lundholm, J., Bass, B., Coffmann,

R. R., Doshi, H., Dunnett, N., Gaffin, S., Koehler,

M., Liu, K. K. Y. and Rowe, B. (2007) ‘Green Roofs

as Urban Ecosystems: Ecological Structures,

Functions, and Services’, BioScience. Oxford

University Press, 57(10), p. 823.

(12) Red Rose Forest, 2014. University of Manchester

Green Roof - Green Wall Policy and Guidance,

Manchester.

(13) Rowe, D.B., 2011. Green roofs as a means of

pollution abatement. Environmental pollution,

159(8-9), pp.2100–10.

Comprehensive literature review of peer reviewed

English language literature. Up to 0.5kg of PM/m2 are

removed by grassed green roofs. Intensive roofs reduce

even more – vegetation plays a key role. They can also

sequester carbon, however their construction is often

more carbon intensive than those of conventional roofs.

Green roofs can effectively retain pollutants like heavy

metals by up to 99%, however this depends on their

age, time of year and magnitude of rainfall.

(14) Royal Haskoning DHV, 2012. Costs and Benefits of

Sustainable Drainage Systems,

(15) Speak, A.F. et al., 2012. Urban particulate pollution

reduction by four species of green roof vegetation

in a UK city. Atmospheric Environment, 61,

pp.283–293.

Green roofs can remove 0.425 (sedum roof) to 3.21g

(grass) PM10/m2/a. Intensive roofs have higher

impacts than extensive roofs.

(16) U.S. Environmental Protection Agency, 2008.

Green Roofs. In Reducing Urban Heat Islands:

Compendium of Strategies. Wasington D.C.: U.S.

Environmental Protection Agency.

Studies have shown up to 75% reduction in demand

for cooling, and 10% for heating (both studies carried

out in Canada). They improve air quality by removing

pollutants, studies having shown a removal of 0.2kg of

PM/m2/a. They can also reduce heavy metals in runoff

by up to 95% and reduce peak runoff as well as total

runoff by 50-100%.

(17) Wolch, J.R., Byrne, J. & Newell, J.P., 2014. Urban

green space, public health, and environmental

justice: The challenge of making cities “just green

enough.” Landscape and Urban Planning, 125,

pp.234–244.

(18) Wong, N. H., Tay, S. F., Wong, R., Ong, C. L. and

Sia, A. (2003) ‘Life cycle cost analysis of rooftop

gardens in Singapore’, Building and Environment,

38(3), pp. 499–509.

(19) Yang, J., Yu, Q. & Gong, P., 2008. Quantifying air

pollution removal by green roofs in Chicago.

Atmospheric Environment, 42(31), pp.7266–7273.

(20) www.thegreenroofcentre.co.uk/green_roofs/faq

(21) http://livingroofs.org/

(22) http://www.greenroofguide.co.uk/

(23) Lee, K. E., Williams, K. J. H., Sargent, L. D.,

Williams, N. S. G. and Johnson, K. A. (2015) ‘40-

second green roof views sustain attention: The

role of micro-breaks in attention restoration’,

Journal of Environmental Psychology, 42, 182–189.








http://www.forestry.gov.uk/pdf/urgp_benefits_of_green_infrastructure.pdf/$FILE/urgp_benefits_of_green_infrastructure.pdf

https://www.asla.org/uploadedFiles/CMS/Green_Roof/Green_Roof_Water_Monitoring_Report.pdf




https://www.researchgate.net/publication/258777935_Green_roof_impact_on_the_hydrological_cycle_components


http://archive.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc46412/nrcc46412.pdf


http://bioscience.oxfordjournals.org/content/57/10/823.full



http://www.estates.manchester.ac.uk/media/services/estatesandfacilities/esteam/University%20of%20Manchester%20Green%20Roof%20Policy%20(approved%20Feb%202015).pdf



http://www.epa.gov/sites/production/files/2014-06/documents/greenroofscompendium.pdf





http://www.thegreenroofcentre.co.uk/green_roofs/faq

http://livingroofs.org/

http://www.greenroofguide.co.uk/




34

EXTENSIVE GREEN ROOFS

Green roofs are distinguished into two main categories: intensive and extensive. Extensive green roofs usually

feature a thin layer of soil medium and plants like succulents, grasses or other low maintenance, low growing

vegetation. They require little to no maintenance and are usually not accessible. By intercepting precipitation

and allowing infiltration in the soil media as well as evaporation and transpiration from plants, extensive green

roofs reduce the impermeable surface of an area. They are most effective in small to medium rainfall events

with low intensities and longer durations.

Benefits Wheel

Landscape context

Shows the contribution of extensive green roofs to the provision of


Green roofs have the same function as any open,

permeable surface: they provide interception and source

control, and are therefore part of the first stages of

treatment. They may be able to provide storage to an

extent, but will need further connection to drainage

systems.

They can be combined with rainwater harvest systems.

They only receive water from the area of the roof.


£55-130/m2 (medium to high). Depends

on type - may be higher for retrofit.

Longer life expectancy than

conventional roofs (up to 3 times).

Relative costs depend on area, location

(and with it the accessibility of the site).

Benefit of not using any additional land.

(3, 6, 14, 18)

Maintenance requirements are minimal

if at all. Usually no requirement of

artificial irrigation or fertilization.

Invasive species removal may be

required, as well as clearing of drains.

(6)

Residential and Industrial, Retrofit

possible. Flat and sloping roofs are

possible. Slopes however influence

drainage and will lead to less water

holding capacity. (6, 12)

Featu

red

Case

Stu

dy

Bridgewater Green Roofs, Somerset

This report investigates the whole life costs of a living roof (extensive green

roof) in Somerset. It compares costs of an exposed roof, a sedum roof and

a biodiverse roof and finds that the biodiverse roof achieves the best

financial and non-financial results, due to a longer life time and insulation

benefits. It also attracts the widest range of animals and so has the greatest

benefits for ecology. It also states that added insulation effects of bio diverse

and sedum living roofs will save approximately 4.9t of CO2 per annum or a

total of 245t over the life of the living roof.

More: The Solution Organisation (2005): Whole Life Costs & Living Roofs

– The Springboard Centre, Bridgewater.

http://www.thesolutionorganisation.com/Living%20roof%20Bridgewater%20

003.pdf

Image: greenroofs.com



35


Health: Access. * Extensive green roofs are usually not

accessible but can provide mental health benefits if they are

visible from other places. (4,17)

Air Quality. * Sedum covered green roofs can remove up

to 200g PM/a/m2 from the atmosphere and provide benefits

through the improvement of air quality. Different types of

vegetation can account for even higher reductions. Studies

have shown that 19m2 of extensive green roof can reduce

pollution by the same amount as a medium sized tree. (13, 15,

16, 19)

Surface Water. * About 50% (27-81%) of runoff can be

retained in small to medium rainfall events by extensive green

roofs, depending on soil thickness and vegetation

characteristics. A study in Brussels has shown that greening

only 10% of possible roofs would lead to overall runoff

reduction of 2.7%. (2, 4, 5, 6, 7, 10, 16)

Fluvial Flood. * Not given.

Water Quality. * The capacity of green roofs to reduce

pollutants is linked to their age (more mature roofs capture

more pollutants), design, season (removal rates are higher in

summer) and species. Overall, they have a positive impact on

water quality. Studies have shown retention of PO4 of up to

80%, and retention of heavy metals of 80-99%. Sedum roofs

are less effective at reducing pollution than herbaceous

perennials. (2,4, 5, 13, 16)

Habitat Provision. * Green roofs can provide important

ecological stepping stones for wildlife and habitats to a number

of even endangered invertebrates. This depends on their

design and species selection as well as maintenance. (4, 6, 11)

Climate Regulation. * Green roofs can reduce

temperatures (up to 75% reduction in cooling demand shown).

They impact positively on the UHI effect by lowering the air

temperature (vegetated areas can decrease air temperatures

by up to 3 degrees). Depending on their vegetation, they can

store and sequester carbon. (1, 4, 8, 9, 13)

Low Flows. * Not given.


Aesthetics. * Ext. green roofs can be designed to be

aesthetically pleasing.

Cultural Activities. * As they are usually not accessible,

ext. green roofs have little potential to provide cultural

benefits.

Property Value. * Studies have mentioned increases in

property value through installation of green roofs but have not

quantified them.

Flood Damage. * By reducing the impermeability of an urban

area, green roofs can help to reduce severity of floods.


Energy savings. Depending on temperature, green roofs

can provide substantial energy savings by cooling a building in

summer (up to 75%0 and providing isolation in winter (up to

10%). Electricity savings could amount to £5.20/m2/yr. They

could play an important role in adapting cities to climate

change.

Mental health. The view of green roofs can provide

relaxation and restoration and so have beneficial effects on

the mental health of those in vicinity.

Noise reduction. Green roofs can impact on acoustic

transfer into and out of a building.

Water quality. Runoff can include high pollution loads from

green roofs than can either be a symptom of the “first flush”

effect after longer dry periods, due to the vegetation or – in

some cases – fertilization. Care needs to be taken to avoid

this through informed design.



36

References:

(1) Coutts, A.M. et al., 2013. Assessing practical

measures to reduce urban heat: Green and cool

roofs. Building and Environment, 70, pp.266–276.

(2) Czemiel Berndtsson, J., 2010. Green roof

performance towards management of runoff water

quantity and quality: A review. Ecological

Engineering, 36(4), pp.351–360.

Numerous studies show a runoff reduction of 27-81%

for extensive roofs. Exact amount depends on rainfall

intensity, substrate and drainage. Runoff water quality

varies greatly but they can contribute significantly to

pollutant reduction. Green roofs can be an effective

tool to manage small storms in urban areas, but

additional measures required for larger storms.



(4) Forest Research, 2010. Benefits of Green

Infrastructure, Farnham: Forest Research.

Extensive green roofs can reduce pollution compared

to convetional roofs. They can reduce runoff by 45%,

and also provide ecological services, being used by

birds and invertebrates.

(5) Glass, C.C., 2007. Green Roof Water Quality and

Quantity Monitoring,




CIRIA. London.

Intensive green roofs require maintenance and are

usually accessible. They provide good contribution to

thermal performance of buildings, as well as good

water retention capacity. Pollution removal is variable.

Can provide great amenity benefits.

(7) Lamera, C. et al., 2013. Green roof impact on the

hydrological cycle components. In EGU 10th

General Assembly. p. 8038.

(8) Lehmann, S., 2014. Low carbon districts: Mitigating


infrastructure. City, Culture and Society, 5(1),

pp.1–8

(9) Liu, K.K.Y. & Baskaran, B., 2003. Thermal

performance of green roofs through field

evaluation, Ottawa.





(11) Oberndorfer, E., Lundholm, J., Bass, B., Coffmann,

R. R., Doshi, H., Dunnett, N., Gaffin, S., Koehler,

M., Liu, K. K. Y. and Rowe, B. (2007) ‘Green Roofs

as Urban Ecosystems: Ecological Structures,

Functions, and Services’, BioScience. Oxford

University Press, 57(10), p. 823.

(12) Red Rose Forest, 2014. University of Manchester

Green Roof - Green Wall Policy and Guidance,

Manchester.

(13) Rowe, D.B., 2011. Green roofs as a means of

pollution abatement. Environmental pollution,

159(8-9), pp.2100–10.

Comprehensive literature review of peer reviewed

English language literature. Up to 0.5kg of PM/m2 are

removed by grassed green roofs. Intensive roofs reduce

even more – vegetation plays a key role. They can also

sequester carbon, however their construction is often

more carbon intensive than those of conventional roofs.

Green roofs can effectively retain pollutants like heavy

metals by up to 99%, however this depends on their

age, time of year and magnitude of rainfall.

(14) Royal Haskoning DHV, 2012. Costs and Benefits of

Sustainable Drainage Systems,

(15) Speak, A.F. et al., 2012. Urban particulate pollution

reduction by four species of green roof vegetation

in a UK city. Atmospheric Environment, 61,

pp.283–293.

Green roofs can remove 0.425 (sedum roof) to 3.21g

(grass) PM10/m2/a. Intensive roofs have higher

impacts than extensive roofs.

(16) U.S. Environmental Protection Agency, 2008.

Green Roofs. In Reducing Urban Heat Islands:

Compendium of Strategies. Wasington D.C.: U.S.

Environmental Protection Agency.

Extensive green roofs reduce runoff by 50-75%.

Studies have shown up to 75% reduction in demand

for cooling, and 10% for heating (both studies carried

out in Canada). They improve air quality by removing

pollutants, studies having shown a removal of 0.2kg of

PM/m2/a. They can also reduce heavy metals in runoff

by up to 95% and reduce peak runoff as well as total

runoff by 50-100%.

(17) Wolch, J.R., Byrne, J. & Newell, J.P., 2014. Urban

green space, public health, and environmental

justice: The challenge of making cities “just green

enough.” Landscape and Urban Planning, 125,

pp.234–244.

(18) Wong, N. H., Tay, S. F., Wong, R., Ong, C. L. and

Sia, A. (2003) ‘Life cycle cost analysis of rooftop

gardens in Singapore’, Building and Environment,

38(3), pp. 499–509.

(19) Yang, J., Yu, Q. & Gong, P., 2008. Quantifying air

pollution removal by green roofs in Chicago.

Atmospheric Environment, 42(31), pp.7266–7273.

(20) http://www.thegreenroofcentre.co.uk/green_roofs/

faq

(21) http://livingroofs.org/

(22) http://www.greenroofguide.co.uk/




http://www.forestry.gov.uk/pdf/urgp_benefits_of_green_infrastructure.pdf/$FILE/urgp_benefits_of_green_infrastructure.pdf

https://www.asla.org/uploadedFiles/CMS/Green_Roof/Green_Roof_Water_Monitoring_Report.pdf




https://www.researchgate.net/publication/258777935_Green_roof_impact_on_the_hydrological_cycle_components


http://archive.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc46412/nrcc46412.pdf





http://www.estates.manchester.ac.uk/media/services/estatesandfacilities/esteam/University%20of%20Manchester%20Green%20Roof%20Policy%20(approved%20Feb%202015).pdf



http://www.epa.gov/sites/production/files/2014-06/documents/greenroofscompendium.pdf







http://livingroofs.org/

http://www.greenroofguide.co.uk/

37

PERMEABLE PAVEMENTS

Permeable pavements are made of material that is itself impermeable to water but the material is laid so that

space is provided where water can infiltrate into the underlying structure. They reduce peak flows and effects

of pollution. They require no additional land take and are therefore highly valuable interventions in dense

areas, especially because they are easily accepted by the community around. An aggregate subbase allows

water quality improvements and attenuation of flows, while a geotextile layer improves pollutant removal and

performance.

Benefits Wheel

Landscape context

Shows the contribution of permeable pavements to the provision of


Permeable Paving provides source control and infiltration

and can be combined with storage systems. They are the

first stage the water passes through. Where runoff cannot

be completely eliminated, conveyance to a storage area

should be designed.


27-40£/m2 (high). Depends on whether

replacement or new development and

type of paving. No need for connection

to sewer system (saves additional

costs). If all costs are taken into

account, they are lower than for

traditional surfacing and drainage. (4, 7)

0.5-1£/m3 of water stored/treated.

Brushing/vacuuming every 6 months -

to prevent the clogging and

accumulation of metals in the top

layers is likely necessary to maintain

good water quality performance.

Clogging however is more an issue

with porous than permeable

pavements. Unlimited design life. (4,5,

7, 8, 14)

Industrial and Domestic. Retrofit

possible. The type of pavement used

depends on expected traffic load and

aesthetic requirements. Only gentle

slopes. Adjacent areas need to be

stabilised to prevent sediment flow into

the paved area. Sand or sediment input

can happen especially during

construction; contractors have to be

made aware of this. (5, 7, 8, 14)

Featu

red

Case

Stu

dy

Permeable paving in parking area. Oregon, USA

In 2004, Environmental Services paved three blocks of streets in the

Westmoreland neighbourhood with permeable pavement that allows water to

go through the street surface and into the ground.

It is the first use of this type of permeable paving material on a public street in

Portland, although similar materials are used locally in parking lots and private

driveways.

Different types of permeable paving were tested in Portland to compare their

performance in reducing runoff. Permeable paving absorbed runoff 27%

quicker than concrete and porous asphalt (60 inches per hour). It also

provides aesthetic benefits

More: https://www.portlandoregon.gov/bes/article/77074

https://www.portlandoregon.gov/bes/article/77074

38


Health: Access. * Can be used in multifunctional areas but

does not provide same benefits as greenspace. Can provide

area for recreational use. (8,15, 14)

Air Quality. Not given.

Surface Water. * 40% more effective peak flow reduction

than conventional pavements, other studies have found runoff

reductions of up to 100%, treating the paved area and to an

extent even runoff from adjacent areas. Runoff generation can

be eliminated. (1, 2, 3, 6, 9, 10, 13, 14)

Fluvial Flood. * Can provide flood prevention downstream

by reducing runoff into rivers.

Water Quality. * Pollutant reductions are very high but can

depend on maintenance. TSS reductions of >60% (58-94),

motor oil, diesel and metals (20-99) can be (nearly) completely

removed. N and P have varying degrees of removal, dependent

on the design of the structure (below ground infiltration). (1,

2, 6, 10, 12)

Habitat Provision. Not given.

Climate Regulation. * Potential to mitigate UHI through

evaporation and storage of water but this depends on various

factors. If combined with other technologies (see below) may

help to reduce emissions. (11, 12, 14)

Low Flows. * Permeable pavements can potentially allow

groundwater recharge and combined with rainwater

harvesting reduce pressure on mains water. (8)


Aesthetics. * May allow grass to grow, creating attractive

green area where otherwise only paving would be present.

Depends on type of pavement used. (7,15)

Cultural Activities. Not given.

Property Value. * Depending on type and quality may add

value. (14)





Water re-use potential –There is high potential of

combination with RWH systems that allow using the water

for non-potable uses. The combination with geothermal heat

pumps (GHPs) enables re-use of water (e.g. for gardening)

along with energy efficient heating/cooling of buildings. This

of course depends on the site context but can provide

sustainable heating without need for fossil fuels (therefore

reducing emissions).

Multi-functionality – Paved surface enables safe and

comfortable use for vehicles and pedestrians while allowing

infiltration and benefitting vegetation, providing treatment

and flow management. While it is not a greenspace itself, it

can improve the accessibility of greenspaces by providing

convenient, safe paths through existing green infrastructure

that integrate well with the landscape.

No additional impacts

*** Indication of confidence. * Literature confirms positive

influence. * Mostly positive results in literature and/or little

literature available. * Varying results in literature, little literature

available

39

References:

(1) Ahiablame, L. M., Engel, B. A. and Chaubey, I.

(2012) ‘Effectiveness of Low Impact Development


Future Research’, Water, Air, & Soil Pollution,

223(7), pp. 4253–4273.

Studies show runoff reductions by 50-93%, with

pollutant removal for various substances ranging

from 20-99%(metals), 58-94%(TSS), 75-85%(N)

and 10-78%(P). Runoff generation can be

eliminated, PPS are therefore a valuable source

control system.




(3) Booth, D.B. & Leavitt, J., (1999) Field Evaluation of

Permeable Pavement Systems for Improved

Stormwater Management. Journal of the American

Planning Association, 65(3), pp.314–325.



(5) Harley, M. & Jenkins, C., (2014). Research to

ascertain the proportion of block paving sales in

England that are permeable, Report for the Sub-

Committee of the Committee on Climate Change.

(6) Imran, H.M., Akib, S. & Karim, M.R., (2013).

Permeable pavement and stormwater management

systems: a review. Environmental technology, 34(17-

20), pp.2649–56.

(7) Interpave, (2008). Understanding Permeable Paving,

Leicester.

Design guidance and description of various available

systems and performances.




CIRIA. London.

(9) Qin, H., Li, Z. & Fu, G., (2013). The effects of low

impact development on urban flooding under

different rainfall characteristics. Journal of

environmental management, 129, pp.577–85.

Runoff reduction of 75% on average through permeable

pavement. Best for smaller storms with short

durations, with peaks in the middle of the event.

(10) Scholz, M. & Grabowiecki, P., (2007). Review of

permeable pavement systems. Building and

Environment, 42(11), pp.3830–3836.

Permeable and porous pavements provide 10-42% more

effective peak flow reduction compared to

conventional asphalts. They provide good water

quality treatment with TSS reductions of about

60% and nearly complete removal of motor oil,

diesel and metals.

(11) Starke, P., Goebel, P. & Coldewey, W., (2010).

Urban evaporation rates for water-permeable

pavements. Water Sci Technol, 62(5), pp.1161–9.

(12) Tota‐Maharaj, K. et al., (2010). The synergy of

permeable pavements and geothermal heat pumps

for stormwater treatment and reuse. Environmental

Technology, 31 (14), pp. 1517-31.

(13) U.S. Environmental Protection Agency (2013).

Stormwater to Street Trees. Washington: USEPA.

(14) Royal Horticultural Society (2016): Front gardens:

permeable paving.

(15) http://www.susdrain.org/delivering-suds/using-

suds/suds-components/source-control/pervious-

surfaces/pervious-surfaces-overview.html

https://engineering.purdue.edu/ecohydrology/Pubs/2012%20WASP%20Ahiablame%20et%20al.pdf





https://www.theccc.org.uk/wp-content/uploads/2014/07/7-ASC-paving-survey-report_for-publication.pdf

http://www.tandfonline.com/doi/abs/10.1080/09593330.2013.782573

http://www.paving.org.uk/commercial/pdf/understanding-permeable-paving.pdf






http://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02731223&AN=54295667&h=gd2mkJUoXEBHK99KoQBJ6Lhqei6gv7ZNx09ZsYmQrbxUxZwgxydduJFBrlA3oOBpGYJZErfpTJEZ2mKmHjQ8ag==&crl=c&resultNs=AdminWebAuth&resultLocal=ErrC


http://www.davey.com/media/183712/Stormwater_to_Street_Trees.pdf

https://www.rhs.org.uk/advice/profile?pid=878

http://www.susdrain.org/delivering-suds/using-suds/suds-components/source-control/pervious-surfaces/pervious-surfaces-overview.html



40

RAINWATER HARVESTING/WATER BUTTS

By collecting water from impermeable surfaces, rainwater harvesting can reduce the volume of runoff and peak

flows and so have a positive impact on surface water flooding. It can vary in scale from single water butts

installed on private properties to underground storage tanks on commercial areas. Costs and effectiveness of

the intervention depend on its scale and design, but benefits from reduced runoff are only significant for larger

systems.

Benefits Wheel

Landscape context

Shows the contribution of rainwater harvesting to the provision of


Rainwater Harvesting acts as source control and storage.

It prevents runoff by taking it up at its source. In one

year, it is estimated that 24,000l can on average be saved

from a roof in the UK, preventing this additional runoff.

Once RWH systems have reached their capacity, they

cannot contribute any more to reducing runoff. Ways of

dealing with overflows have to be incorporated – this

could be infiltration systems like Rain Gardens, for

example, taking up water spilling out of water butt

outlets.

The impact of RWH is mostly realised on a local scale,

but cumulative effects where RWH is implemented on as

many properties as possible are to be expected.


£10+ for water butts, £2000-4000 for a

complete domestic system. Retrofit is

possible but likely more expensive for

entire systems. Depends on scale and

type of the system (e.g. gravity fed or

pump system) and existing connections.

Costs: £0.1-0.4 per m2 (4,7)

Typical maintenance activities: cleaning

and inspection. Depends on context

and type of system.

Context: Residential, Industrial. Retrofit

and use in high density urban areas

possible.

Connection to rainwater pipes is

necessary. More water is collected from

sloping roofs. (7)

Featu

red

Case

Stu

dy

Rainwater Harvesting at Calke Abbey, National

Trust

With total costs of £11,181.86, the National Trust installed a

Rainwater Harvesting System on its property in Calke Abbey to

reduce pressures on mains water and make use of the relatively

high volumes of rainfall. Estimated savings from mains water use

are £625 per year at the moment, and the harvested rainwater is

now the main supply for garden irrigation where previously mains

water was used.

More: https://www.nationaltrust.org.uk/calke-

abbey/documents/calke-abbey---building-design-guide.pdf

https://www.nationaltrust.org.uk/calke-abbey/documents/calke-abbey---building-design-guide.pdf

https://www.nationaltrust.org.uk/calke-abbey/documents/calke-abbey---building-design-guide.pdf

41


Health: Access. * Rainwater Harvesting Systems provide

no access to or to the benefits of accessing green space.

Air Quality. * Rainwater Harvesting Systems have no

impact on air quality.

Surface Water. * High peak flow and volume reductions

can be achieved depending on the size and design of the

system/butt and the saturation of the system. An estimated

24,000l/a can be saved from the average roof (11). However,

there is little evidence on the scale of this impact on flooding.

(1,3,8)

Fluvial Flood. * Rainwater Harvesting systems are unlikely

to contribute to reducing fluvial flooding apart from reducing

runoff into water courses.

Water Quality. * Rainwater Harvesting provides no

opportunity for reducing pollution and may even deteriorate

the quality of water. However, it does intercept water initially

and can so reduce the first flush effect.(2,5)

Habitat Provision. * Rainwater Harvesting Systems have no

capacity to provide habitats for wildlife.

Climate Regulation. * Rainwater harvesting can have

positive impacts by saving water and thus energy, but if pumps

are used the emissions might outweigh the benefits. (3,6)

Low Flows. * RWH can indirectly reduce abstraction rates by

reducing demands on mains water (up to 80% of mains water

use in industrial/commercial buildings, 30-50 in domestic) (12).

However, there are few studies on the scale of this impact.


Aesthetics. * Water butts can be used as planters and so

provide aesthetic benefits. Tanks can be stored underground

so as to not impact on the landscape or be designed to

provide amenity value. (8, 10)

Cultural Activities. * Rainwater Harvesting Systems

provide no opportunity for cultural activities or further

cultural benefits.

Property Value. * Rainwater Harvesting Systems may be able

to add value to a property, especially if they are extensive.

Flood Damage. * Due to their impact on surface water

flooding, Rainwater Harvesting Systems may influence the

extent of flooding downstream.


Economic. Even if there is no increase in property value,

rainwater harvesting systems and water butts can save

significant amounts on water bills (depending on type of

water use and intensity of use).

Water re-use. During periods of hosepipe bans, as they can

happen more frequently, harvested rainwater can be used to

water vegetation and keep it beautiful. For bigger systems,

the ability to meet water demand independent of mains

water can provide sustainability and resilience benefits.

Energy use. Where complete RWH systems are installed

with pumps, the intensity of energy use can be increased

compared to mains water. This can have net negative impacts

on emissions from the system. This is not the case for water

butts and other storage systems without pumps.

Water quality. While it is generally not an issue, water

harvested from roofs can hold high concentrations of

pollutants, especially after long dry periods. However, there

is little evidence of this occurring in significant frequency. It is

important to connect drain pipes correctly, so only rainwater

is discharged into the water storage



42

References:

(1) Ashley, R. M., Nowell, R., Gersonius, B., & Walker,

L. (2011). Surface Water Management and Urban

Green Infrastructure, 44(0), 1–76.

(2) Berwick, N., & Wade, D. R. (2013). A Critical




(3) CIRIA. (2014). Demonstrating the multiple benefits

of SuDS - a business case.

(4) Environment Agency. (2015). Cost estimation for


(5) Helmreich, B., & Horn, H. (2009). Opportunities in

rainwater harvesting. Desalination, 248(1-3), 118–

124.

(6) Parkes, C., Kershaw, H,, Hart, J. Sibille, R., Grant,

Z (2010):Energy and carbon implications of

rainwater harvesting and greywater recycling.

Bristol: Environment Agency.

(7) Woods Ballard, B., Wilson, S., Udale-Clarke, H.,

Illman, S., Ahsley, R., Kellagher, R. (2015): The

Suds Manual. London: CIRIA.

(8) Susdrain (2016):


suds/suds-components/source-control/rainwater-

harvesting.html

(9) Savetherain.info (2016):

http://www.savetherain.info/media-

centre/rainwater-harvesting-faa qs.aspx

(10) Rainwaterharvesting Ltd (2016):

http://www.rainwaterharvesting.co.uk/rainwaterhar

vesting-simple-guide.php

(11) BBC (2016)

http://www.bbc.co.uk/gardening/basics/techniques/

watering_savingwater1.shtml

(12) YouGen.co.uk (2016), Rain harvesting

http://www.yougen.co.uk/energy-

saving/Rain+Harvesting/.



http://nora.nerc.ac.uk/502911/




https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/291745/scho0610bsmq-e-e.pdf

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/291745/scho0610bsmq-e-e.pdf



http://www.rainwaterharvesting.co.uk/rainwaterharvesting-simple-guide.php

http://www.rainwaterharvesting.co.uk/rainwaterharvesting-simple-guide.php

http://www.bbc.co.uk/gardening/basics/techniques/watering_savingwater1.shtml

http://www.bbc.co.uk/gardening/basics/techniques/watering_savingwater1.shtml

http://www.yougen.co.uk/energy-saving/Rain+Harvesting/

http://www.yougen.co.uk/energy-saving/Rain+Harvesting/

43

EXISTING GREEN & BLUE

INFRASTRUCTURE

Image: Craig Boney (CC BY-NC-ND 2.0)

44

PUBLIC PARKS AND GARDENS

Public Parks and Gardens are important existing assets of an urban environment, with 91% of people in the UK

believing that public parks and open spaces improve their quality of life (4). While high land prices and pressure

from different competing objectives often makes the development of a new park in an area unlikely (although

not impossible – see for example the Thames Barrier Park Case study) it is all the more important to protect

existing parks and manage them in a way that maximises the multiple benefits laid out below. Benefits from

parks, as far as they have been monetised, are significant: Edinburgh, for example, has shown that its public

parks show a SROI of on average £12 for every £1 invested, and Camley Street Park (London) alone has

calculated a total of £2.8 million in ecosystem service benefits per year.

Benefits Wheel

Landscape context

Shows the contribution of parks to the provision of ecosystem services.


Parks have recorded increasing visitor numbers, showing

that there is a demand for their use. Over 10% of people

visit or pass through their local parks daily, and over 50%

at least once per month. Especially for parents and

households with children, parks are a significant resource,

socially as well as culturally, with over 80% of people with

children under 10 in the household using their local park

at least monthly. Parks and open space have been

suggested to be the third most frequently used public

service after GP surgeries and hospitals. However,

budgets are being cut and staff numbers reduced, leading

to increased user charges and potential deterioration of

their condition.

Parks – depending on their size and design – often

constitute a combination of different types of green

infrastructure type ‘interventions’ and their value to

society and the environment depends on their different

parts. To understand what different singular ‘modules’ in

a park do (e.g. trees, ponds), or how these could be

incorporated, please refer to additional factsheets. Parks

have the additional benefit of bringing all these single

modules together and potentially achieving an effect that

is larger than the sum of its parts. (4, 8).

Maintenance Costs

Average management costs of parks in 2013/14: £6,410/ha. (8) Often maintenance activities are already

carried out by volunteer groups and this can provide a valuable opportunity to protect existing parks with

the additional social benefits that volunteer groups provide.

Featu

red

Case

Stu

dy

Camley Street Natural Park

Camley Street Natural Park now provides access to nature in a

densely populated area. It contains a pond, a meadow, a marsh and

woodland providing a habitat for a variety of wildlife.

The natural park has been managed by London Wildlife Trust since

its opening, on behalf of London Borough of Camden. Some of the

benefits are: Habitat provision (70 species of trees, 32 species of

bees, 20 species of amphibians and reptiles, 75 species of birds, 8

species of fish), regulating noise, providing educational space,

enabling access to nature (with 15,000-20,000 visitors each year).

Total ecosystem service value: £2.8 million per year.

http://www.atkinsglobal.co.uk/~/media/Files/A/Atkins-

Corporate/group/cs/Camley-st-natural-park.pdf

Image: www.wildlondon.org.uk

http://www.atkinsglobal.co.uk/~/media/Files/A/Atkins-Corporate/group/cs/Camley-st-natural-park.pdf

http://www.atkinsglobal.co.uk/~/media/Files/A/Atkins-Corporate/group/cs/Camley-st-natural-park.pdf

http://www.wildlondon.org.uk/

45


Health: Access. * A greater quantity of urban green space is

generally associated with better health. The “healthiest” areas

in England (i.e. with the higher levels of activity and lowest

levels of obesity) have 20% higher green spaces than the least

healthy areas. Being exposed to park settings has also been

linked to better attention performance, reduced

cardiovascular morbidity in males and better recovery rates.

However, even though a lot of evidence points to this

positive link, there are diverse results in the literature –

which possibly points to the importance of park design in

enabling the provision of benefits. (2,4,5,6,9,10,12,13,14,20)

Air Quality. * While research focusing on parks specifically

is limited, it is clear that trees have a big impact on air quality.

Air quality within parks is often better than outside, as are air

temperatures. This is true for PM10 but also other pollutants

like NOx and SOx. (2, 6, 10, 18, 20)

Surface Water. * Due to high infiltration rates, grassed

areas are able to nearly completely eliminate runoff, therefore

having a positive impact on surface water flooding. In

Manchester areas with less green space are more susceptible

to surface water flooding. The effect however depends on

type of vegetation and intensity/duration or rainfall as well as

factors like soil type and compaction. (2, 9, 15, 16, 18)

Fluvial Flood. * To an extent, parks can provide flood

storage if they are designed to do so, and this should be taken

into account when designing new parks as well as when

existing ones are restored or redeveloped. (18)

Water Quality. * Through water infiltration, parks can

prevent pollutants from reaching waterbodies and streams.

Fertilization and pesticide use however can have a negative

impact. (2, 16, 18)

Habitat Provision. * Often, parks have been found to be the

most biodiverse type of urban of green space. However, this

can be due to exotic species. Larger, more diverse and less

isolated parks harbour more native species. (2,3, 16, 17, 20,

22)

Climate Regulation. * Parks, especially those with high tree

cover, can act as carbon sinks. A study in Leicester has shown

that 97.3% of the carbon pool stored in urban vegetation is

stored in trees. Parks provide resilience against increasing

temperatures and the UHI effect. Air temperatures in London

have been shown to be 2-8 degrees lower in greenspaces. This

could mean that the current provision on green space in

London saves 16-22 lives per day during heatwaves. Parks can

influence the air quality in surrounding areas as the

temperature difference can lead to “park breeze” into

surrounding built up areas. (1,2, 6, 7, 9, 18, 20)

Low Flows. * Parks have been shown to contribute

significantly to groundwater recharge due to their high

infiltration rates (over 30%). Grassed areas are able to nearly

completely eliminate runoff. (9,16)


Aesthetics. * The aesthetic value of parks can be very high

and is for example shown through their impact on property

values as well as stress and mental fatigue. A study in Zurich

found parks and urban forests to be associated with an 87%

recovery ration for stress and 40% enhancement of positive

feelings. Some studies show these benefits even from just

viewing green space (2, 19)

Cultural Activities. * Many parks provide venues for

annual festivals, meeting spaces for community groups and

therefore add to the cultural service provision in an area.

Parks, as accessible local green spaces, can give rise to

cultural activities like bird watching, painting or

photography. (2,4, 6, 20)

Property Value. * There are wide ranges between different

cities and countries but parks almost always have a positive

impact on property values. While park size is a factor, even

small parks can have an impact. (e.g. a study in the

Netherlands has shown an increase in 5-12% for houses

overlooking attractive areas, and 6-12% for houses

overlooking open spaces) (2, 11, 18, 20)

Flood Damage. * Due to their impact on surface water

and their potential contribution to mitigating fluvial flooding,

parks can reduce severity of flooding and the damage caused

by it.

46


Crime: Higher levels of high quality green space provision

are correlated with lower crimes. Apart from the economic

benefits, this means a positive impact on the community and

the mental wellbeing of residents. Studies in the US have

shown more than 25% reduced crime rates and aggressive

behaviour in areas with green space provision than in those

with less. This seems to be due to the environment deterring

criminal activity by increasing use of the space and natural

surveillance, but also to green space preventing mental

fatigue. (4,9, 21)

Local Economy: Small businesses are more likely to settle

in areas with good parks, open spaces and recreational areas.

Visitor spending has been shown to be higher in attractive

areas, and while this is not specific to parks, they are often

connected to shopping trips in one way or another. (9, 18)

Mental health Parks provide important mental health

benefits by offering somewhere to escape from daily life,

exercise and build a connection with nature. 30% lower

depression rates in areas with higher greenspace have been

shown. Biodiversity has also been shown to impact on the

psychological benefit of visiting parks, with the species

richness being more important than the area of the green

space. A study in Bristol has shown that children are more

likely to engage in active play in areas with green spaces. A

study in Greenwich showed that dissatisfaction with urban

green space is related to poor mental health. (4, 8, 9)

Social Cohesion: A study in Vienna has shown an increased

“attachment” to an area in places with a perceived higher

supply and quality of greenspace. There is evidence showing

that particularly if teenagers are catered for with specific

facilities and equipment, parks have the potential to cater for

multiple ethnic groups, potentially improving social cohesion

in the neighbourhood. (4,9,20)

Crime: Poor quality green space can actually enforce

antisocial behaviour. Parks that are not maintained well can

become hotspots for crime and vandalism, and lead to

perceptions of unsafety.

Property value: As with crime, poor quality green space

can actually have the reverse effect of what it is meant to

achieve and reduce values of properties where it is perceived

to be an unsafe area.



References:

(1) Armson, D., P. Stringer, and A.R. Ennos. 2012.

“The Effect of Tree Shade and Grass on Surface

and Globe Temperatures in an Urban Area.”

Urban Forestry & Urban Greening 11 (3): 245–55.

(2) BOP Consulting. 2013. “Green Spaces: The

Benefits for London.”

(3) Chamberlain, D.E., S. Gough, H. Vaughan, J.A.

Vickery, and G.F. Appleton. 2007. “Determinants

of Bird Species Richness in Public Green Spaces:

Capsule Bird Species Richness Showed Consistent

Positive Correlations with Site Area and Rough

Grass.” Bird Study 54 (1). Taylor & Francis Group:

87–97.


Environment. 2005. “Decent Parks? Decent

Behaviour? The Link between the Quality of Parks

and User Behaviour” 1–17.

(5) Coombes, Emma, Andrew P Jones, and Melvyn

Hillsdon. 2010. “The Relationship of Physical

Activity and Overweight to Objectively Measured

Green Space Accessibility and Use.” Social Science

& Medicine (1982) 70 (6): 816–22.

(6) Faculty of Public Health. 2010. “Great Outdoors:


Space To Improve Wellbeing”.

(7) Forestry Commission. 2013. “Air Temperature

Regulation by Urban Trees and Green

Infrastructure.” Farnham.

(8) Heritage Lottery Fund. 2014. “State of UK Public

Parks.” London.

(9) Konijnendijk, Cecil C, Matilda Annerstedt, Anders

Busse Nielsen, and Sreetheran Maruthaveeran.

2013. “Benefits of Urban Parks. A Systematic

Review.” Copenhagen&Alnarp.

(10) Lovasi, G S, J W Quinn, K M Neckerman, M S

Perzanowski, and A Rundle. 2008. “Children Living

in Areas with More Street Trees Have Lower

Prevalence of Asthma.” Journal of Epidemiology

and Community Health 62 (7): 647–49.

(11) Luttik, Joke. 2000. “The Value of Trees, Water and

Open Space as Reflected by House Prices in the

Netherlands.” Landscape and Urban Planning 48

(3-4): 161–67.


https://www.cityoflondon.gov.uk/business/economic-research-and-information/research-publications/Documents/research-2013/Green-Spaces-The-Benefits-for-London.pdf



http://webarchive.nationalarchives.gov.uk/20110118095356/http:/www.cabe.org.uk/files/decent-parks-decent-behaviour.pdf

http://webarchive.nationalarchives.gov.uk/20110118095356/http:/www.cabe.org.uk/files/decent-parks-decent-behaviour.pdf

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3759315&tool=pmcentrez&rendertype=abstract


http://www.fph.org.uk/uploads/bs_great_outdoors.pdf


https://www.hlf.org.uk/state-uk-public-parks

http://curis.ku.dk/ws/files/44944034/ifpra_park_benefits_review_final_version.pdf

http://curis.ku.dk/ws/files/44944034/ifpra_park_benefits_review_final_version.pdf




47

(12) McCormack, Gavin R, Melanie Rock, Ann M

Toohey, and Danica Hignell. 2010. “Characteristics

of Urban Parks Associated with Park Use and

Physical Activity: A Review of Qualitative

Research.” Health & Place 16 (4): 712–26.

(13) Mitchell, Richard, and Frank Popham. 2007.

“Greenspace, Urbanity and Health: Relationships

in England.” Journal of Epidemiology and

Community Health 61 (8): 681–83.

(14) Richardson, Elizabeth A, and Richard Mitchell.

2010. “Gender Differences in Relationships

between Urban Green Space and Health in the

United Kingdom.” Social Science & Medicine

(1982) 71 (3): 568–75.

(15) Rogers, K., Jaluzot, A. and Neilan, C. (2011) Green

Benefits in Victoria Business Improvement District.

(16) Speak, A. F., Mizgajski, A. and Borysiak, J. (2015)

‘Allotment gardens and parks: Provision of

ecosystem services with an emphasis on

biodiversity’, Urban Forestry & Urban Greening,

14(4), pp. 772–781.

(17) Stagoll, Karen, David B. Lindenmayer, Emma

Knight, Joern Fischer, and Adrian D. Manning.

2012. “Large Trees Are Keystone Structures in

Urban Parks.” Conservation Letters 5 (2): 115–22.

(18) Sunderland, T. 2012. “Microeconomic Evidence for

the Benefits of Investment in the Environment -

Review.” Natural England Research Reports,

Number 033. Vol. 2.

(19) Tyrväinen, Liisa, Ann Ojala, Kalevi Korpela, Timo

Lanki, Yuko Tsunetsugu, and Takahide Kagawa.

2014. “The Influence of Urban Green

Environments on Stress Relief Measures: A Field

Experiment.” Journal of Environmental Psychology

38 (June): 1–9.

(20) Woolley, Helen, Sian Rose, Matthew Carmona,

and Jonathan Freedman. 2004. “The Value of

Public Space.” Exchange Organizational Behavior

Teaching Journal. London.

(21) Kuo, F. E. and Sullivan, W. C. (2001) ‘Environment

and Crime in the Inner City: Does Vegetation

Reduce Crime?’, Environment and Behavior, 33(3),

pp. 343–367.

(22) Forestry Commission. Benefits of Greenspace:

Park and Garden Habitats.

http://www.forestry.gov.uk/fr/urgc-7edjrw

Web references and useful weblinks:

American Planning Association: How Cities Use Parks

for Green Infrastructure, Briefing Paper.

https://www.planning.org/cityparks/briefingpapers/greeni

nfrastructure.htm

National Recreation and Park Association: Pocket Parks

https://www.nrpa.org/uploadedFiles/nrpaorg/Grants_and

_Partners/Recreation_and_Health/Resources/Issue_Brie

fs/Pocket-Parks.pdf

Forest Research: Greenspace initiatives. Urban Parks

and Gardens: http://www.forestry.gov.uk/fr/urgc-7ekebr

Greenspace Scotland.: http://greenspacescotland.org.uk/

Big Lottery Fund. Parks for People Funding:

https://www.biglotteryfund.org.uk/prog_parks_people.



https://www.researchgate.net/publication/6208584_Greenspace_urbanity_and_health_Relationships_in_England







http://publications.naturalengland.org.uk/publication/32031



https://www.designcouncil.org.uk/sites/default/files/asset/document/the-value-of-public-space1.pdf

https://www.designcouncil.org.uk/sites/default/files/asset/document/the-value-of-public-space1.pdf

http://eab.sagepub.com/content/33/3/343.short?rss=1&ssource=mfc

http://www.forestry.gov.uk/fr/urgc-7edjrw

https://www.planning.org/cityparks/briefingpapers/greeninfrastructure.htm

https://www.planning.org/cityparks/briefingpapers/greeninfrastructure.htm

https://www.nrpa.org/uploadedFiles/nrpaorg/Grants_and_Partners/Recreation_and_Health/Resources/Issue_Briefs/Pocket-Parks.pdf



http://greenspacescotland.org.uk/

https://www.biglotteryfund.org.uk/prog_parks_people

48

COMMUNITY GARDENS & ALLOTMENTS

Orchards and allotments show similar benefits to parks and other open areas regarding their environmental

and partly social benefit, as they are comprised of similar structural elements (trees, shrubs, meadow like

areas) and therefore exhibit similar properties in terms of infiltration and water quality. However, what makes

these types of urban green spaces unique is the social and cultural aspect of food production and land

ownership in an otherwise urban environment. The ecosystem services provided depend on how the

allotments/orchards are used and guidance for allotment owners and users should be considered within the

management of surface water and multiple ecosystem services.

Benefits Wheel

Landscape context

Shows the contribution of allotments to the provision of ecosystem


The high land take of allotments makes them unlikely to

be used on a large scale. As they cover a significant

amount of land, they have the potential to contribute

locally not only by infiltrating runoff and providing

amenity benefits but also provide the opportunity to

incorporate other interventions – e.g ponds, swales –

within them, maximising multiple benefits.

As they are not accessible to the public, certain benefits –

access, social cohesion, education, … - can only be

provided on a fairly limited scale. However, this is likely

to benefit particularly older demographics, which can be

an important aspect.


The cost of allotments or orchards are

hard to estimate and are more

dependent on the opportunity costs

from lost opportunities for housing/

commercial develop-ment. Users of

allotments pay for accessing the space,

with fees varying in different areas but

on average between £30-£40 for a

250m2 plot (2).

As allotments are managed privately,

maintenance costs depend on the

individual owner. Avoiding soil

compaction, planting and maintaining

buffer strips and allowing wild habitat

can maximise provision of ecosystem

services

The main factor determining the

feasibility of allotments is the availability

of suitable land. Demand is usually given,

with many allotments having waiting lists

for plots. Opportunities for new creation

are undeveloped land or reclaiming of

previous allotment sites, as well as

protection of existing sites

Featu

red

Case

Stu

dy

‘The social, health and wellbeing benefits of allotments:

five societies in Newcastle’ (Ferres, M. and Townshend, T. G.,

2012)

Three main reasons for having an allotment were identified: (1) Being able

to grow one’s food, (2) the enjoyment and pleasure obtained by the activity

itself, (3) dedicating time to relaxation and exercise.

This demonstrates psychological, physical and social benefits, with allotment

holders saying that contact with nature at the allotments is an important

factor in their lives. 79% of participants state they obtain psychological or

spiritual benefits from having an allotment and 72% state they gain physical

benefits.

More: http://www.ncl.ac.uk/guru/documents/EWP47.pdf

http://www.ncl.ac.uk/guru/documents/EWP47.pdf

49


Health: Access. * While allotments are not freely accessible,

they provide significant health benefits to a wide number of

people, especially in an older age group. They provide an

important space to form community ties and social cohesion.

(3,5,6,7)

Air Quality. * Air quality is not a significant benefit provided

by allotments, hover they can have an impact on a regional

scale, with trees being able to filter pollutants. Orchards are

likely to have a more significant impact. (3,13)

Surface Water. * Open surfaces allow infiltration and can

increase groundwater recharge, therefore improving low flow

conditions. Infiltration on vegetated areas is 20%+ higher than

on impermeable ground, and grassed areas have been shown to

have the potential to nearly completely eliminate runoff.

(3,4,15,16,17,18)

Fluvial Flood. * Allotments can only contribute to reducing

fluvial flood risk by infiltrating water before it reaches streams.

(17)

Water Quality. * Bioretention can improve water quality

in many aspects, and it is likely that similar processes occur

in allotment soils. Water and with it pollutants are captured

by existing vegetation this can be increased by installing filter

and buffer strips in runoff pathways. (3,4,16)

Habitat Provision. * Allotments and orchards can provide

great habitats for pollinators and other insects as well as

mammals, birds and amphibians etc. More plant species have

been found in allotments than in parks in a study in

Manchester, although no rare species were found.(2,3)

Climate Regulation. * Allotments and orchards provide

mitigation of the UHI effect by lowering air temperatures and

allowing influx of fresh air, and store carbon in vegetation

and soils. This benefit is likely to be greater from orchards.

(3,14)

Low Flows. * Infiltration can enable groundwater recharge

and so have a positive impact on low flows.


Aesthetics. * The aesthetic quality of a site is the second

most important aspect in choosing an allotment site, it can

therefore be inferred that they generate significant aesthetic

benefits.(6,7)

Cultural Activities. * Growing food is an – in urban

environments rare - cultural and educational activity and

allotments are often used to experiment with exotic as well as

native species. (5,6,7,8,9,10)

Property Value. * Attractive views of green spaces have

been shown to increase property values by 10+%, however

there is no specific literature on the effect of allotments. (19)

Flood Damage. * By reducing the impermeability of an

urban area, allotments can help to reduce severity of

floods.(17)

50


Mental Health. Allotments have been shown to generate a

sense of pride, engagement with nature and an increased

well-being is reported by 80% of allotment gardeners. They

are especially important as community resources and

generate multi-cultural meeting spaces.

Food Production. People who own an allotment eat more

fresh fruit and vegetables than those who 0don’t. A study in

Manchester has quantified the economic benefit of food

production on allotments to be on average 698£ per plot and

year (3). Another report has found the total food production

in London in urban gardens to be £1.4 million per year.

Water Quality. The use of pesticides and fertilizer can have

a negative impact on the water quality of receiving systems.

Organic fertilizer and pest control through natural

mechanisms (e.g. providing habitat for natural predators)

should be encouraged.

Flooding. Allowing runoff to collect in allotments is only

viable as long as the area does not suffer from permanent

waterlogging. Hydraulic connectivity should be as high as

possible, and structures increasing infiltration – e.g. trees or

infiltration trenches – as well as storage structures like ponds

should be incorporated.



References:

General/Guidance:

(1) Environment Strategy Unit Chichester District

Council (no date) A Guide to Setting up and

Managing a Community Orchard.

(2) Natural England (2007). Wildlife on Allotments.

This document gives guidance on obtaining an

allotment and making it a valuable resource for

wildlife, advising that prizes for a plot of 250m2 are

on average between £30 and 40, but can be much

higher in dense areas. The habitat can be enhanced by

installing nesting boxes, hedgerows, ponds or similar,

and the report gives further guidance on what plants

to use and how to manage a plot in order to

encourage biodiversity.

(3) Speak, A. F., Mizgajski, A. and Borysiak, J. (2015)

‘Allotment gardens and parks: Provision of

ecosystem services with an emphasis on

biodiversity’, Urban Forestry & Urban Greening,

14(4), pp. 772–781.

This study is an attempt to assess and compare the

ecosystem services provided by AGs in Manchester,

UK, and Poznań, Poland as well as a comparison to

city parks. The results of this study show that AGs can

be highly species-rich environments and may offer a

method of food production that does not incur as

many trade-offs with biodiversity as other land uses.

The study also shows that the highest potential for

benefits arises from provisioning and cultural services,

e.g. generating knowledge, recreation, food production

and genetic resources. It is worth noting that many of

the additional ecosystem services beyond food

production, provided by AGs, have spatial impacts

beyond the confines of the gardens. Local climate

regulation, flood protection and air quality regulation

will especially benefit a large number of local residents

in cities at the neighbourhood scale.




This report investigates the benefits of urban green

infrastructure, specifically with regards to the

management of surface water quantity and quality.

Social Benefits:

(5) van den Berg, A. E., van Winsum-Westra, M., de

Vries, S. and van Dillen, S. M. E. (2010) ‘Allotment

gardening and health: a comparative survey among

allotment gardeners and their neighbors without

an allotment.’, Environmental health : a global

access science source, 9, p. 74.

After adjusting for income, education level, gender,

stressful life events, physical activity in winter, and

access to a garden at home as covariates, both

younger and older allotment gardeners reported higher

levels of physical activity during the summer than

neighbors in corresponding age categories. The impacts

of allotment gardening on health and well-being were

moderated by age. Allotment gardeners of 62 years

and older scored significantly or marginally better on all

measures of health and well-being than neighbors in

the same age category. Health and well-being of

younger allotment gardeners did not differ from

younger neighbors. The greater health and well-being

benefits of allotment gardening for older gardeners

may be related to the finding that older allotment

gardeners were more oriented towards gardening and

being active, and less towards passive relaxation.

(6) Ferres, M. and Townshend, T. G. (2012) ‘The

social, health and wellbeing benefits of allotments:

five societies in Newcastle’, School of

Architecture, Planning and Landscape, 47, pp. 1–

47.

This report investigates the benefits of having an

allotment for residents of Newcastle. It seeks to fill a

gap in the knowledge around why people choose to

maintain an allotment. Three main reasons were

identified: growing one’s own food, enjoyment of the

activity itself, and dedicating time to relaxation and

exercise. In the study, 79% of participants state they

obtain psychological or spiritual benefits from having

an allotment and 72% state they gain physical

http://www.chichester.gov.uk/CHttpHandler.ashx?id=4768&p=0

http://www.chichester.gov.uk/CHttpHandler.ashx?id=4768&p=0

http://www.nsalg.org.uk/wp-content/uploads/2012/05/wildlife_on_allotments1-Natural-England1.pdf






http://www.ncl.ac.uk/guru/documents/EWP47.pdf

51

benefits. However, allotment holders also have

concerns regarding the future of the allotments in

Newcastle, with many people saying that the biggest

threat comes from development pressure by local

councils.

(7) Ferris, J., Norman, C. and Sempik, J. (2001)

‘People, Land and Sustainability: Community

Gardens and the Social Dimension of Sustainable

Development’, Social Policy & Administration,

35(5), pp. 559–568.

Community gardens vary enormously in what they

offer, according to local needs and circumstance. This

article reports on research and experience from the

USA. The context in which these findings are discussed

is the implementation of Local Agenda 21 and

sustainable development policies. In particular,

emphasis is given to exploring the social dimension of

sustainable development policies by linking issues of

health, education, community development and food

security with the use of green space in towns and

cities. The article concludes that the use of urban open

spaces for parks and gardens is closely associated with

environmental justice and equity.

(8) Glover, T. D., Parry, D. C., & Shinew, K. J. (2005).

Building relationships, accessing resources:

Mobilizing social capital in community garden

contexts. Journal of Leisure Research, 37(4), 450-

474.

This paper explores the role of social capital and

formation of relationships in the context of community

gardening. CG are presented as settings for building

social networks and a knowledge base and can

therefore provide important social and cultural

benefits.

(9) Flachs, A. (2010) ‘Food For Thought: The Social

Impact of Community Gardens in the Greater

Cleveland Area’, Electronic Green Journal, 1(30).

This paper explores the social and cultural effects of

urban gardening in the greater Cleveland area.

Gardening is shown to have a multitude of motivating

factors, including economic, environmental, political,

social, and nutritional.

(10) Joe Howe (2002) Planning for Urban Food: The

Experience of Two UK Cities, Planning Practice &

Research, 17:2, 125-144

This article puts urban food growing in the context of

the Agenda21 and discusses the role of allotments in

urban policy and sustainability. It finds multiple

important drivers in using an allotment, and pressures

on their development and use.

(11) Woolley, H., Rose, S., Carmona, M. and Freedman,

J. (2004) The Value of Public Space, Exchange

Organizational Behavior Teaching Journal. London.

This report mentions especially the social benefits of

allotment and community gardens as benefits gained

from this type of public space. Allotments have for

example been shown to encourage cross-cultural

community ties.

(12) Sustain (2014). Reaping Rewards. Can

Communities Grow a Million Meals for London?

Based on this analysis, and knowledge of the types and

sizes of food growing spaces throughout the 2,200+

membership of the Capital Growth network, this report

estimates that London's community food growers could

be growing as much as £1.4 million worth of food over

the course of a year.


(14) Forestry Commission (20130. Air Temperature

Regulation by Urban Trees and Green

Infrastructure. Farnham.

Surface Water Management





286. doi: 10.1016/j.ufug.2013.04.001.

This study assessed the impact of trees upon urban

surface water runoff by measuring the runoff from

9m2 plots covered by grass, asphalt, and asphalt with

a tree planted in the centre. It was found that, while

grass almost totally eliminated surface runoff, trees

and their associated tree pits, reduced runoff from

asphalt by as much as 62%.




Water environment research : a research publication of

the Water Environment Federation, 73(1), pp. 5–14.

Urban stormwater runoff contains a broad range of

pollutants that are transported to natural water

systems. A practice known as biological retention

(bioretention) has been suggested to manage

stormwater runoff from small, developed areas.

Bioretention facilities consist of porous soil, a topping

layer of hardwood mulch, and a variety of different

plant species. Reductions in concentrations of all

metals were excellent (> 90%) with specific metal

removals of 15 to 145 mg/m2 per event. Moderate

reductions of TKN, ammonium, and phosphorus levels

were found (60 to 80%).

(17) Perry, T. and Nawaz, R. (2008) ‘An investigation

into the extent and impacts of hard surfacing of

domestic gardens in an area of Leeds, United

Kingdom’, Landscape and Urban Planning, 86(1), pp.

1–13. doi: 10.1016/j.landurbplan.2007.12.004.

A study in Leeds has linked the increase in paved front

gardens (and therefore increase in impermeable area)

to an increased severity in surface water flooding in

that area. A 13% increase in paved area was observed

over 33 years, of which 75% is due to paving of front

gardens, that lead to a predicted 12% increase of

average surface water runoff. This prediction was

reflected by actual events in Leeds, where heavy

rainfall led to more frequent and severe flooding.

(18) Yao, L., Chen, L., Wei, W. and Sun, R. (2015)

‘Potential reduction in urban runoff by green

spaces in Beijing: A scenario analysis’, Urban


http://onlinelibrary.wiley.com/doi/10.1111/1467-9515.t01-1-00253/abstract

http://lin.ca/sites/default/files/attachments/CCLR11-46.pdf

http://escholarship.org/uc/item/6bh7j4z4

http://dx.doi.org/10.1080/02697450220145904

http://www.sustainweb.org/publications/reaping_rewards/





52

The results show that urban green space offers

significant potential for runoff mitigation. In 2012, a

total of 97.9 million m3 of excess surface runoff was

retained by urban green space; adding nearly 11%

more tree canopy was projected to increase runoff

retention by >30%, contributing to considerable

benefits of urban rainwater regulation. At a more

detailed scale, there were apparent internal variations.

Urban function zones with >70% developed land

showed less mitigation of runoff, while green zones

(vegetation >60%), which occupied only 15.54% of the

total area, contributed 31.07% of runoff reduction.

(19) Luttik, Joke. 2000. “The Value of Trees, Water and

Open Space as Reflected by House Prices in the

Netherlands.” Landscape and Urban Planning 48

(3-4): 161–67.

http://www.nsalg.org.uk/

https://www.cambridge.gov.uk/content/benefits-

allotment

http://greenspacescotland.org.uk/our-growing-

community.aspx

http://www.allotment-garden.org/

http://www.nsalg.org.uk/

https://www.cambridge.gov.uk/content/benefits-allotment

https://www.cambridge.gov.uk/content/benefits-allotment

http://greenspacescotland.org.uk/our-growing-community.aspx

http://greenspacescotland.org.uk/our-growing-community.aspx

53

URBAN RIVERS

Rivers have in many cases provided the resources and benefits necessary for the development of cities. Yet, in

urban areas, rivers have often been seen as a threat to infrastructure and human health rather than as a

resource, leading to their increasing degradation. Many benefits that arise from protecting rivers and

restoration projects can be similar to those from public parks where access is given and the restoration is

designed to provide a similar environment, it can therefore be useful to refer to this factsheet to understand

further benefits. Opportunities for river restoration in parks and other open spaces may also be more easily

found than in higher density urban environments.

Benefits Wheel

Landscape context

Shows the contribution of rivers to the provision of ecosystem services.


Rivers receive water as runoff from their surroundings,

even more so due to the increasing impermeability of the

urban environment. Sewers – meant to carry surface

water flow, but often also carrying pollutants from

misconnections – also discharge into watercourses. In

addition, other pressures are present in the urban

environment: air pollution from traffic can cause

acidification. Pesticides from roadsides or amenity areas

can reach the water, as well as fertilisers. Construction

sites can cause high sediment inflow. (Environment

Agency 2009). Past culverting and straightening streams

and disconnecting them from floodplains has also had a

degrading impact.

These pressures threaten the quality of rivers and their

value as habitats, but also the benefits they can bring to

people, some of which are represented in the benefits

wheel on the left, and explained in more detail on the

next page..

Maintenance Costs

To improve the state of urban rivers and restore the benefits they provide, there are many interventions that

can be taken. Habitat can be restored, for example by removing hard riverbanks and re-meandering.

Reducing runoff and pollution from hard surface by installing SuDS can improve water quality and work on a

wider scale (7, 8, 19). The costs for river restoration are very variable. A study on restoration projects

carried out in the EU has shown that costs can range between 100 to 3000€ (equivalent to about 70-2300£)

per metre of river restored (9). The cost of SuDS depends on their type – see other factsheets..

Featu

red

Case

Stu

dy

Mayesbrook Park

The Mayesbrook Park project demonstrates how a green infrastructure approach

to urban river restoration is a strong alternative to traditional hard engineering.

By using green infrastructure to address flood-water management, the project has

created an attractive public amenity, while the communities that surround the

park and the wildlife within it are now able to cope better with the effects of

climate change. The overall benefits are substantial relative to the planned

investment. The lifetime value of restoring the site across the four ecosystem

service categories (provisioning, regulatory, cultural and supporting) yields a grand

total of calculated benefits of around £27 million, even if ‘likely significant positive

benefits’ for the regulation of air quality and microclimate are excluded. This is

compared to the estimated costs of the whole Mayesbrook Park restoration

scheme at £3.8 million including the river restoration works. This produces an

excellent lifetime benefit-to-cost ratio of £7 of benefits for every £1 invested.

http://publications.naturalengland.org.uk/publication/11909565?category=49002

http://publications.naturalengland.org.uk/publication/11909565?category=49002

54


Health: Access. * Improved open spaces – in parks and

other public open spaces, river restoration can improve their

quality, as has been shown for example by the restoration

project of the River Quaggy, running through Sutcliffe Park,

where about 30% of the visitors only started visiting after the

restoration project had improved the area, and 82% reported

feeling differently in the park due to better recreational

opportunities and higher biodiversity and the surrounding

natural environment. Recreational opportunities are

improved through increased opportunities for angling, water

sports and low intensity activities. Improving pathways to

enable active transport can have impacts on physical health.

(1,2,3,4, 5,6,8,11)

Air Quality. * Air quality is likely to be improved due to

denser vegetation and the transport of fresh air along the

river corridors – however this could also mean the

distribution of pollutants from busy roads. (1,16, 17)

Surface Water. * Draining landscapes into rivers rather

than sewers could mean less risk of surface water flooding,

however, it might increase flood risk from rivers. River

restoration projects have to be carefully planned to

accommodate for this function. Creation of floodplain and

forest habitats increases runoff infiltration and so reduces the

amount of water that needs to be drained away, with suitable

natural habitat like medium dense woodlands and meadows

likely reducing runoff by appr. 20%. (1, 4, 8, 13,19)

Fluvial Flood. * Restoring rivers, i.e. re-meandering them

and establishing vegetation, creating wetlands, slows the flow

and increases water storage capacity. It has to be understood

where the issue is created (i.e., where does the water come

from – upstream or surface water draining into the river?)

and the correct measures have to be taken according to this.

Erosion regulation can decrease the need for dredging

downstream, reducing flood risk and also labour intensity. (1,

4, 8, 19)

Water Quality. * Freshwater systems can dilute and store

pollution – however, only to a certain level. River restoration

and protection through GI can impact positively on a river’s

health: Filter strips and permeable surfaces are specifically

important close to rivers to intercept polluted runoff from

discharging directly into the river. Preventing polluted runoff

from entering the stream by pre-treating it in ponds or

wetlands is an important step to reducing this pressure

further. (1, 8, 9)

Habitat Provision. * Rivers are amongst the UK’s most

diverse and rich ecosystem, and provide ecological

connectivity through a landscape. Almost all rivers have been

degraded. River restoration has been shown to improve the

quality of water and habitat – an improvement of 1-3 classes in

the WFD status compared to previous conditions has been

found. Morphological status had also improved to moderate in

almost half of the case studies, with a third even reaching

“good” status (1,8, 9, 18)

Climate Regulation. * Water bodies can have a cooling

effect on their local area and so mitigate UHI effect. Wetlands

and ponds that might be created through river restoration

along with soils and vegetation can store carbon. The effect is

size dependent (1, 15). In Seoul, daylighting of a a culverted

river and vegetating the surrounding area has led to an average

temperature of 14 degrees C lower than surrounding urban

area (1, 4, 16)

Low Flows. * Depending on their characteristics,

groundwater recharge can occur from rivers. Flow regimes

are usually improved after restoration, although this depends

on the type of restoration and the drivers of the flow regime.

(1, 4)

55


Aesthetics. * river landscapes are one of the most

attractive landscapes, and this aesthetic quality provides

many benefits by drawing people to the area. The effect on

mental health has been described above and is also reflected

in property values. About 60% of the case studies evaluated

in the 2004 URBEM report showed improvement of

aesthetics after the river restoration project. (1, 2, 3, 4, 5, 6)

Cultural Activities. * Reconnecting people to the natural

environment (which in turn increases happiness) can be

achieved by restoring natural landscapes in urban settings

and making them accessible. This also increases the

possibility to use them as educational resources, especially

in urban settings where similar rural environments may not

be as easily accessible. Water is connected to many

activities that are not only recreational and benefit human

health but also have cultural traditions connected to them,

like angling or bird watching. At Mayesbrook Park (see case

studies), the benefits from cultural service provision through

restoration of an urban stream can be valued at £820,000

per year (1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13)

Property Value. * View of water or a garden adjacent to

water can have a significant positive impact on property

values, with studies showing increases in value from 10% -

even more than 30%. (1, 8, 18)

Flood Damage. * Through their contribution to surface

water drainage and regulating flows, healthy river ecosystems

can help reduce severity of flooding. The Mayes Brook

Restoration, for example, shows an annual benefit in

improved flood management of £10,000. (4).


Improved sales – high quality environments lead to an

increase in money spent in local businesses and also

encourage businesses to settle in an area.

Employment – settlement of businesses in an attractive

area can increase the local employment rate. Additionally,

through the creation of parks new opportunities for

businesses (cafes, outdoor recreation facilities) can improve

the employment situation.

Mental health: water bodies have been found to be

particularly significant in shaping people’s sense of place and

improving their mental wellbeing. They provide attractive,

stimulating features that have the ability to restore

attentiveness and inspire creativity, and landscapes with

water are perceived as more restorative than those without

– even to the extent that urban landscapes featuring water

are seen to be as restorative as green landscapes.

Additionally, the improved recreational opportunities can

give rise to increased social activities. Views of water and the

sound of water have been shown to alleviate stress more

effectively than other types of natural setting.

Crime and social cohesion– as restoration provides an

opportunity for partnership working, the improved

community ownership of places where restoration has been

undertaken by an engaged community is likely to reduce

crime and vandalism in the area (see “Access” and “Public

Parks” factsheet) and increase the social connections

between people living in the area.

No additional impacts.



56

References:

(1) Maltby, E., Ormerod, S., Acreman, M., Blackwell,

M., Durance, I., Everard, M., Morris, J., Spray, C.

(2011) Freshwaters – Open Waters, Wetlands and

Floodplains. In: The UK National Ecosystem

Assessment Technical Report. UK National

Ecosystem Assessment, UNEP-WCMC,

Cambridge.

(2) van den Berg, M., Wendel-Vos, W., van Poppel, M.,

Kemper, H., van Mechelen, W. and Maas, J. (2015)

‘Health benefits of green spaces in the living

environment: A systematic review of

epidemiological studies’, Urban Forestry & Urban

Greening, 14(4), pp. 806–816.


Environment (2005) Decent parks? Decent

behaviour?: The link between the quality of parks

and user behaviour, pp.1–17.

(4) Everard, M. and Moggridge, H. L. (2012)

‘Rediscovering the value of urban rivers’, (April

2011), pp. 293–314.

(5) Jackson, R. J., Watson, T. D., Tsiu, A., Shulaker, B.,

Hopp, S. and Popovic, M. (2014) Urban River

Parkways. Los Angeles.





(7) Palmer, M. A., Bernhardt, E. S., Allan, J. D., Lake, P.

S., Alexander, G., Brooks, S (2005) ‘Standards for

ecologically successful river restoration’, Journal of

Applied Ecology, 42(2), pp. 208–217.

(8) RESTORE (2013) Rivers by Design. Bristol.

(9) Schanze, J., Olfert, A., Tourbier, J. T., Gersdorf, I.

and Schwager, T. (2004) Existing Urban River

Rehabilitation Schemes. Wallingford.

(10) Völker, S. & Kistemann, T., (2013) “I’m always



and Düsseldorf, Germany. Social science &

medicine (1982), 78, pp.113–24.





scenes’, Journal of Environmental Psychology, 30(4),

pp. 482–493.

(12) Zelenski, J.M. & Nisbet, E.K. (2012). Happiness and

Feeling Connected: The Distinct Role of Nature

Relatedness. Environment and Behavior, 46(1),

pp.3–23.

(13) Sunderland, T. (2012) Microeconomic Evidence for

the Benefits of Investment in the Environment -

Review, Natural England Research Reports, Number

033.

(14) Environment Agency (2009) Water for life and

livelihoods. River Basin and Management Plan Thames

River Basin District. Annex G: Pressures and risks.

(15) Kayranli, B., Scholz, M., Mustafa, A. and Hedmark,

Å. (2009) ‘Carbon Storage and Fluxes within

Freshwater Wetlands: a Critical Review’, Wetlands,

30(1), pp. 111–124.

(16) Hathway, E. A. and Sharples, S. (2012) ‘The

interaction of rivers and urban form in mitigating

the Urban Heat Island effect: A UK case study’,

Building and Environment, 58, pp. 14–22.

(17) Wood, C. R., Pauscher, L., Ward, H. C., Kotthaus,

S., Barlow, J., Gouvea, M., Lane, S. E. and

Grimmond, C. S. B. (2013) ‘Wind observations

above an urban river using a new lidar technique,

scintillometry and anemometry’, Science of the

Total Environment. Elsevier.

(18) International Association of Certified Home

Inspectors, Inc. (InterNACHI) (2016): Constructed

Wetlands: The Economic Benefits of Runoff

Controls.

(19) http://www.ecrr.org/RiverRestoration/Urban

RiverRestoration/tabid/3177/Default.aspx

More links:

(20) http://www.urbem.net/index.html

(21) https://www.restorerivers.eu/.

http://uknea.unep-wcmc.org/

http://uknea.unep-wcmc.org/





http://eprints.uwe.ac.uk/20256/

https://ehs.ph.ucla.edu/sites/default/files/downloads/Urban%20River%20Parkways%20Full%20Report_1.pdf

https://ehs.ph.ucla.edu/sites/default/files/downloads/Urban%20River%20Parkways%20Full%20Report_1.pdf




https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/297315/LIT8146_7024a9.pdf

http://www.urbem.net/WP2/WP2_case_studies.pdf

http://www.urbem.net/WP2/WP2_case_studies.pdf




http://eab.sagepub.com/content/46/1/3.abstract

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/289945/geth0910bswh-e-e.pdf




http://dx.doi.org/10.1016/j.scitotenv.2012.10.061





http://www.ecrr.org/RiverRestoration/UrbanRiverRestoration/tabid/3177/Default.aspx

http://www.ecrr.org/RiverRestoration/UrbanRiverRestoration/tabid/3177/Default.aspx

http://www.urbem.net/index.html

https://www.restorerivers.eu/

57

PRIVATE GARDENS

In 2002, an estimated 27 million people in the UK owned gardens. Domestic gardens contribute about a

quarter of the total urban area in typical cities in the UK and contribute up to 86% of the total number of

trees in a city. Especially small gardens are important, as they contribute the greatest proportion to the total

area of gardens and the accumulated number of structures such as ponds, nesting sites or compost heaps is

significant at the city scale. This indicates the importance of gardens on a wider scale, not only for humans but

also nature. Private gardens are mainly used for relaxation and recreation, with over a third of garden owners

surveyed (2011) naming these as main activities; with gardening, eating, drying laundry and socialising being

other common activities. Over 80% of gardens are used for more than one of these activities. (4, 14)

Benefits Wheel

Landscape context

Shows the contribution of parks to the provision of ecosystem services.


The vegetated, permeable area provided by gardens is

reduced each year due to development pressures,

individual choices regarding the design of the garden and

its maintenance and to provide space for private vehicles.

In London, for example, an area of 2.5 Hyde Parks

(2.5x142 ha) of vegetated garden land is lost each year

(14), and in a case study area in Leeds, paved area in

gardens increased by 13% over the course of 10 years

(12). While domestic gardens have significant positive

benefits for their owners, they are not accessible to the

wider public and do therefore not contribute to

increasing public access to green space. Especially

domestic back gardens may not even provide aesthetic

benefits as they may be hidden behind house fronts or

fences/walls. This has implications on the ability of

gardens to provide benefits – on a local as well as a city-

wide scale. Fragmented habitats can also be unable to

support wildlife even though the conditions would be

given, connecting these habitats (e.g. through tree lined

streets for birds) and managing them on a larger scale,

e.g. as a group of gardens in an area, could be an

interesting opportunity to maximise their habitat

potential. Benefits from individual gardens to the wider

public could also be maximised by strategically managing

gardens on a larger scale than the individual plot.

Maximising benefits: how could we make the most of gardens?

Manage gardens on a larger scale: this could allow habitat connectivity and optimise benefit provision for all.

Improve soil structure and include ponds to maximise infiltration and allow storage of water in designated

areas. Reduce use of pesticides and fertilizer to prevent polluted runoff and use of mains water for irrigation.

Open up walls to make gardens visible and increase the attractiveness of the area. Inform on the ways

gardens can be used for exercise, education and play in different demographics..

Featu

red

Case

Stu

dy

Perry, T. and Nawaz, R. (2008) ‘An investigation into

the extent and impacts of hard surfacing of domestic

gardens in an area of Leeds, United Kingdom’,

Landscape and Urban Planning, 86(1), pp. 1–13.

A study in Leeds has linked the increase in paved front gardens (and

therefore increase in impermeable area) to an increased severity in

surface water flooding in that area. A 13% increase in paved area was

observed over 33 years, of which 75% is due to paving of front gardens,

that lead to a predicted 12% increase of average surface water runoff.

This prediction was reflected by actual events in Leeds, where heavy

rainfall led to more frequent and severe flooding (Perry and Nawaz,

2008). While this study was focussed on front gardens being paved, there

is no reason to assume that the loss of back gardens would have a

different effect.

58


Health: Access. * For those able to use them, they can

provide increased physical fitness, connection to nature,

improved relaxation and recovery from trauma, and similar

benefits related to stress avoidance and cognitive function.

Gardening in one’s own garden has been shown to provide

greater satisfaction than gardening in community/shared

gardens. Where visible, the increased green space may help

reduce mental fatigue and so have a positive impact on crime

rates in an area. Private Gardens may have an especially

important effect on young children due to being more readily

accessible for children and providing a safe area for play and

exercise. Private Gardens can also be hugely important

resources for the elderly, however there can be barriers from

decreased physical ability and lack of support. (1, 2, 4, 6, 8,

13)

Air Quality. * Especially in gardens with trees (at least

certain types) air quality can be significantly improved. This is

dependent on the type of vegetation used and where it is

planted. Trees are especially positive if they are on the

leeward side of a high pollution area (e.g. a busy road). They

can not only benefit those owning the domestic garden but

the area surrounding them – depending on their size and

location. However, there is little direct evidence available and

effects are certainly only on a small scale. (2)

Surface Water. * Plants and trees intercept rain and slow

runoff, contributing to an attenuation of the peak flow and

volume reduction of runoff through increased infiltration.

However, heavy and prolonged rainfall, with potential

additional runoff from adjacent areas, can lead to waterlogging

of the soil. This depends on local characteristics such as soil

type and can be exacerbated by compacting the soil, e.g.

through heavy footfall or parking of vehicles. (2, 12, 13, 17)

Fluvial Flood. * Urbanisation and decreased permeability of

surfaces has been shown to impact the magnitude of flooding

by increasing the amount of runoff a river receives. Increasing

permeability of an area by 30% could lead to as much as a

doubling in the magnitude of 100 year return period floods.

Protecting permeable areas is therefore a significant

contribution to keeping flood risk as low as possible. (9)

Water Quality. * Reducing runoff improves water quality as

less pollutants are carried into surface water bodies, but also

because biological processes in the soil break down pollutants.

Bioretention (the breakdown of pollutants in structures

consisting of porous soil, mulch and various plants) has been

shown to have significant potential to reduce pollution in

runoff. Especially metals can be nearly completely (>90%)

removed, ammonium and phosphorous have been found to be

reduced by 60-80%. Nitrate, however, can be increased

through bioretention treatment. Private gardens, especially if

they are managed traditionally, are likely to contribute to

nitrogen and pesticide pollution and could so even have a

negative impact. (2,3)

Habitat Provision. * Especially for invertebrates and birds,

even small domestic gardens can provide an important habitat,

but also for some animals that used to be common in low-

intensity farmland (e.g. hedgehogs, frogs, bumblebees). They

are likely to support a fairly generalist array of species, though

the importance of this should not be underestimated. Gardens

have been shown to harbour more plant species (a study

found the entire garden flora across the UK to consist of 1056

species) than any other form of urban green space. Plant

composition can be homogenous though and include many

non-natives. Another important factor can be the size of

gardens: the ability to provide biodiversity is often related to

the area and connectivity. While gardens have the potential to

provide very valuable habitats, the way they are managed

influences the realisation thereof greatly. (2, 5, 7, 10, 11, 13,

15)

Climate Regulation. * A 10% increase in veg surfaces would

help control summer temperature increase (predicted 4

degrees) due to climate change (modelling study in

Manchester). Additionally, the soil can store carbon, especially

if disturbance is minimised. An average of 2.5 kg m-2 of carbon

is stored in domestic gardens with 83% in soil (to 600mm

depth), 16% in trees and shrubs and only 0.6% on average in

grass and herbaceous plants. (2, 13)

Low Flows. * Infiltration allows groundwater recharge.

Grassed areas are able to nearly completely eliminate runoff.

However, increased water use in summer may occur and

increase pressure on mains water. (2)

59


Aesthetics. * Gardens, where they are visible, provide high

aesthetic benefits for the neighbourhood. In a study in

Sheffield published in 2000, more than 50% surveyed stated

the fact that gardening created “a more beautiful

environment” as a contribution gardens make to the urban

environment. (4)

Cultural Activities. * Gardening has been linked to

increased sense of self-esteem, identity and ownership. They

can lead to strong place attachment and provide a forum for

interaction between family members. Gardens allow playful

activities as well as growing food, gardening to shape a place

after one’s own imagination or creative activities like

painting or photography. Private gardens may, however,

completely discourage wider social interaction by providing

a clear barrier to the outside through hedges and walls –

this is dependent on their layout and the way they are used.

Contrarily, it has also been found that private gardens

encourage social interaction between neighbours as

contacts are made across the garden fence – a study

published in 2000 found that 23% of garden users value the

opportunity to meet neighbours when in the garden. (1, 6,

8, 16)

Property Value. * It is widely accepted that gardens add

value to a property. A survey by HomeSearch found that a

garden added 20% in value compared to a house without a

garden. (19)

Flood Damage. * While a single garden will have no

significant impact, case studies like the previously mentioned

one in Leeds show that the loss of a proportion of gardens in

an area can contribute significantly to increased damage from

surface water flooding).


Energy savings. Sheltering vegetation could reduce energy

costs for heating and cooling – on average 30% cooling

energy savings have been found. These can be maximised by

choosing vegetation with a high albedo to increase the

reflection of light and with it heat. At the same time, this

relates to soil water availability, as evaporation and

transpiration are the main reasons for the cooling effect.

Winter heating savings can also be gained if gardens are used

to plant hedges to insulate from wind (while avoiding shading

the house too much or directing wind tunnels towards the

house), 17% have been suggested for houses in Scotland,

although there is less literature. (2,17)

(Mental) Health. Gardens and gardening provide benefits

through the physical exercise that they can facilitate as well

as through providing a ‘retreat’ from everyday life and

enabling interaction with nature. Reduced mortality, lowered

blood pressure and cholesterol levels, increased bone density

have been linked to gardening, as well as a later onset of

dementia. Regular physical exercise reduces risk of coronary

heart disease. The low intensity, regular exercise that

gardening provides can be very beneficial. Gardening helps

reduce depression and anxiety, and encourages creativity and

self-expression. Views of nature encourage faster recovery

from illnesses and increase attention, alertness and improved

moods. Especially landscapes with high natural resemblance

provide restorative benefits. (1,2,4)

Food. Food production is another potential activity carried

out in private gardens. It has been shown that people owning

an allotment are more likely to consume fresh fruit and

vegetables, and this is likely transferable to private gardens.

However, there is little literature on the extent of food

production in private gardens or the implications it has. (16)

Carbon Emissions. Management of gardens can lead to an

increase in emissions. This can be due either to the products

and services used (greenhouses, peat, plastics etc) or the

activities carried out (lawn mowing…). This means it is

important to be conscious of how to manage a garden for it

to be environmentally sustainable. (2)

Water Use. The need for irrigation can increase water use

in a garden and so demand on mains water and energy. This

can have negative impacts on low flows and carbon

emissions, or if not done decrease the cooling potential and

aesthetic value. Choosing the right plants is important. (2)

Water Quality. Using fertilizers and pesticides can have

negative impacts on the water quality of receiving waters. If

possible, these should not be used or substituted by organic

products to minimise impacts. Keeping a compost heap can

provide fertilizer and reduce waste production. (3, 11)

Habitat Provision. Introduction of invasive species can be a

problem. Also, using pesticides can diminish the value of

gardens as a habitat. Native plants should be preferred and

management intensities should be kept at a reasonable level –

introducing areas for wildlife, like wildflower strips or leaving

piles of leaf litter and dead wood can increase the value as a

habitat. Domestic cats can also present a threat to wildlife.

(7, 11)



60

References:

(1) Bhatti, M. (2006) ‘“When I”m in the garden I can

create my own paradise’: Homes and gardens in

later life’, The Sociological Review, 54(2), pp. 318–

341.

(2) Cameron, R., Blanusa, T., Taylor, J.,

Salisbury, A., Halstead, A., Henricot, B. and

Thompson, K. (2012) The domestic garden:

its contribution to urban green

infrastructure. Urban Forestry and Urban

Greening, 11 (2). pp. 129-137.

The review suggests that there are significant

differences in both form and management of domestic

gardens which radically influence the benefits.

Nevertheless, gardens can play a strong role in

improving the environmental impact of the domestic

curtilage, e.g. by insulating houses against temperature

extremes they can reduce domestic energy use.

Gardens also improve localized air cooling, help

mitigate flooding and provide a haven for wildlife. Less

favourable aspects include contributions of gardens

and gardening to greenhouse gas emissions, misuse of

fertilizers and pesticides, and introduction of alien

plant species. Due to the close proximity to the home

and hence accessibility for many, possibly the greatest

benefit of the domestic garden is on human health and

well-being, but further work is required to define this

clearly within the wider context of green infrastructure.




Water environment research: a research

publication of the Water Environment Federation,

73(1), pp. 5–14.

(4) Dunnett, N. and Qasim, M. (2000)

‘Perceived Benefits to Human Well-being of

Urban Gardens’, HortTechnology, 10(1), pp.

40–45.

Private gardens occupy a significant proportion of the

total surface area of a British city. For many people,

the garden represents their only contact with nature

and their chance to express themselves creatively. Yet

relatively little research has been carried out on the

role and value of such gardens to human well-being.

We report in this paper on a major survey on the role

of private, urban gardens in human well-being,

conducted with a wide cross-section of randomly

selected garden owners from the city of Sheffield,

England, over the summer of 1995.

(5) Gaston, K. J., Warren, P. H., Thompson, K. and

Smith, R. M. (2005) ‘Urban Domestic Gardens

(IV): The Extent of the Resource and its

Associated Features’, Biodiversity and

Conservation, 14(14), pp. 3327–3349.

(6) Gigliotti, C. M. and Jarrott, S. E. (2010) ‘Effects of

Horticulture Therapy on Engagement and Affect’,

Canadian Journal on Aging / La Revue canadienne

du vieillissement. Cambridge University Press,

24(04), p. 367.

(7) Goddard, M. A., Dougill, A. J. and Benton, T.

G. (2010) ‘Scaling up from gardens:

biodiversity conservation in urban

environments.’, Trends in ecology &

evolution, 25(2), pp. 90–8.

A scale-dependent tension is apparent in garden

management, whereby the individual garden is much

smaller than the unit of management needed to retain

viable populations. To overcome this, here we suggest

mechanisms for encouraging 'wildlife-friendly'

management of collections of gardens across scales

from the neighbourhood to the city.

(8) Gross, H. and Lane, N. (2007) ‘Landscapes of the

lifespan: Exploring accounts of own gardens and

gardening’, Journal of Environmental Psychology,

27(3), pp. 225–241.

(9) Hollis, G. E. (1975) ‘The effect of

urbanization on floods of different

recurrence interval’, Water Resources

Research, 11(3), pp. 431–435.

Studies have shown that the urbanization of a

catchment can drastically change the flood

characteristics of a river. Published results are

synthesized to show the general relationship between

the increase in flood flows following urbanization and

both the percentage of the basin paved and the flood

recurrence interval. In general, (1) floods with a return

period of a year or longer are not affected by a 5%

paving of their catchment, (2) small floods may be

increased by 10 times by urbanization, (3) floods with

a return period of 100 yr may be doubled in size by a

30% paving of the basin, and (4) the effect of

urbanization declines, in relative terms, as flood

recurrence intervals increase.

(10) Loram, A., Thompson, K., Warren, P. H. and

Gaston, K. J. (2008) ‘Urban domestic gardens (XII):

The richness and composition of the flora in five

UK cities’, Journal of Vegetation Science, 19(3), pp.

321–330.

(11) Loram, A., Warren, P., Thompson, K. and Gaston,

K. (2011) ‘Urban domestic gardens: the effects of

human interventions on garden composition.’,

Environmental management, 48(4), pp. 808–24.

(12) Perry, T. and Nawaz, R. (2008) ‘An

investigation into the extent and impacts of

hard surfacing of domestic gardens in an

area of Leeds, United Kingdom’, Landscape

and Urban Planning, 86(1), pp. 1–13.

(13) Royal Horticultural Society (2011) Gardening

matters: Urban gardens. London.

(14) Smith, C. (2010) London: Garden City?

Investigating the changing anatomy of London’s

private gardens, and the scale of their loss.,

http://centaur.reading.ac.uk/26212/1/The%20urban%20domestic%20garden%20UFUG%206Jan2012.pdf



https://www.rhs.org.uk/science/pdf/climate-and-sustainability/urban-greening/gardening-matters-urban-greening

http://www.wildlondon.org.uk/sites/default/files/files/London%20Garden%20City%20-%20full%20report.pdf

61

Greenspace Information for Greater London.

London.

(15) Smith, R. M., Warren, P. H., Thompson, K. and

Gaston, K. J. (2005) ‘Urban domestic gardens (VI):

environmental correlates of invertebrate species

richness’, Biodiversity and Conservation, 15(8), pp.

2415–2438.

(16) Taylor, J. R. and Lovell, S. T. (2013) ‘Urban home

food gardens in the Global North: research

traditions and future directions’, Agriculture and

Human Values, 31(2), pp. 285–305.

(17) Tompkins, E. L. and Eakin, H. (2012) ‘Managing

private and public adaptation to climate change’,

Global Environmental Change, 22(1), pp. 3–11.

(18) Royal Horticultural Society (2016) Waterlogging

and Flooding.

www.rhs.org.uk/Advice/Profile?PID=235 (accessed

on 04/05/16)

Advice on preventing and dealing with water logging

(19) This Is Money (2015): So the 'Waitrose effect'

adds 12% to your home's value - but what else

will? Ten top factors that boost a property's

price...

http://www.thisismoney.co.uk/money/mortgagesho

me/article-3033530/Ten-factors-boost-property-s-

price.html

(Accessed on 04/05/2016


http://www.rhs.org.uk/Advice/Profile?PID=235

http://www.thisismoney.co.uk/money/mortgageshome/article-3033530/Ten-factors-boost-property-s-price.html



62

ACCESS

While green spaces have numerous benefits that arise from passive use, like viewing it, from the effect is has

on air quality or infiltration or through improving aesthetics – in short, benefits that arise without a human

actually having to step into the space – there are a number of benefits that can only be gained by using green

space actively. Even for some those benefits that can be gained through passive use – like mental health

wellbeing from viewing green space – the space has to be visually accessible. Many of the services green

infrastructure provides only turn into benefits when access to the space itself is granted. This is not only a

question of putting in doors or pathways, but of making accessing a greenspace safe, attractive and easy and

providing the right environment for people to enjoy benefits. This means, access is in a way also a question of

design – especially as poor quality green space is often not used and can mean negative impacts rather than

positive ones. This does not only apply to parks or general amenity spaces but also green roofs, pocket parks

and similar, and these opportunities should not be underestimated in providing access to green spaces in a

dense urban environment.

Benefits of accessible green space

Mental wellbeing. One in four people in England experience poor mental health at any given time. Green spaces can

contribute to improved mental wellbeing either by encouraging physical exercise and play, providing space for “escape” and have

been shown to make significant contributions to an individual’s wellbeing in many different ways: Some of the mental health

benefits do not necessarily need physical access to a green space but can already be increased by providing a view of them as it is

the aesthetic experience that gives rise to the positive effects (1). There is evidence on the impact of quality of the green space

at hand (2). Having access to green space has been shown to improve mental health considerably and sustainably (3), and natural

views can promote drops in blood pressure, increase focus and reduce feelings of stress, even if only short exposure (40

seconds) happens (4). Children with ADD have been found to benefit from activity in public, especially green spaces (5). Play in

vegetated areas has been shown to inspire more imaginative activities and breaks during schooldays improve learning for

children. Social development through play with others is also an important benefit of these areas (1).

Connection with nature and sense of place are important factors in an individual’s wellbeing and have been shown to be

connected to greenspaces6.

Parks and other green areas provide meeting spaces and venues for social events. This can increase social interaction over a

neighbourhood and increase residents’ overall satisfaction with their area (17).

Physical Wellbeing. The ability to exercise and travel actively has impacts on physical wellbeing. Green spaces have been

shown to facilitate physical exercise for those living near them, and streets with trees show higher cycle traffic than those

without. Examples of benefits are:

Increased likelihood of physical activity and therefore lower obesity rates and lower rates of cardiovascular diseases. People

who live furthest away from public green space are 27% more likely to suffer from obesity (1, 8, 9, 10).

Lower overall mortality rates – although differences have been found between different demographic groups, overall a

positive relationship between green space provision and health has been found (11).

Lower air temperatures during heatwaves – green spaces (where they are big enough) can provide shelter from hot

temperatures during prolonged periods outside in the urban environment (17).

Economic Benefits. Attractive areas lead to higher business investment and more visitor-spending. Additionally, jobs can be

created in the maintenance and creation of green spaces (5, 7). While some of the benefits laid out below arise from improved

mental and physical wellbeing, it is worth showing the contribution they can make to the economy:

Obesity is an ever increasing strain on the NHS and is linked to physical inactivity (1).

Millions of working days are lost due to stress related employee absence (1, 2).

NHS Scotland has been estimated to save £85 million per year if only 1 in 100 inactive people took adequate exercise (5).

Featu

red

Case

Stu

dy

Finlathen Park, Dundee.

This research is part of the Scottish Government’s GreenHealth

project. Participatory techniques have been used in a case study

to identify community opinions on current uses of urban green

and open spaces, and options for the future.

Findings show the importance of the multiple services provided

by green spaces, such as places for relaxation and escape, and

desires to improve the quality and range of benefits.

More:

http://www.hutton.ac.uk/sites/default/files/files/no5%20greenspace

%20services.pdf

http://www.hutton.ac.uk/sites/default/files/files/no5%20greenspace%20services.pdf

http://www.hutton.ac.uk/sites/default/files/files/no5%20greenspace%20services.pdf

63

Enabling Access

Physical Accessibility Maintenance Information

For many people, but especially for

groups like elderly or disabled, physical

access and the state of the environment

can inhibit use of a greenspace. Improve

access with:

Signs and maps close to and

throughout the park

Maintenance of footpaths

Public transport connections

Visible lack of maintenance can have a

negative impact on the use of green

space. Be aware of:

Litter removal and repair of

damage/vandalism

Overgrown vegetation and dog mess

(Potential trade-off: overgrown, wild

areas may be perceived as untidy but

be important factors for wildlife.

Make sure to designate specific

wildlife areas and provide

explanatory signs.)

Information on how and where

damage should be reported and

rapid response

Lack of information about existence or

facilities available in a greenspace can be

a barrier to its use.

Make information about facilities and

services and how they can be used

easily accessible (e.g. online)

Within the area, maps and signs help

find important services and areas

introduce staff (e.g. rangers,

gardeners, volunteers) into the area

to provide a first point of contact

and community interaction

Safety Comfort Community Ownership

Perceived safety risks are a key barrier

to the use of green spaces. Improve

access with:

Sufficient lighting. Street lighting has

been shown to reduce levels of

crime, and increase levels of

perceived safeness.

Avoid dense wooded13 or shrubby

areas, and maintain lines of sight and

visibility of exits throughout the

area, and take advantage of existing

infrastructure and buildings for

natural surveillance (e.g. visibility

form cafes, offices…).

Wide main paths to give pedestrians

enough space to pass by.

While a greenspace consisting of only

vegetation and pathways may provide a

nice corridor to walk through, ensuring

certain needs can be met locally can

increase time spent in a space and its

attractiveness to new groups.

Especially in bigger areas, having well

maintained facilities addressing

different target groups like cafes and

public toilets can increase use by

existing user groups and attract new

groups.

Providing specific areas for dogs

(increase use by dog owners and

make other user groups feel more

comfortable)

Local communities often want to be

involved of the management of ‘their’

space. This can work in multiple ways

and be coordinated via existing groups

(e.g. schools) or ones that are

specifically set up for a particular space:

Involving ‘problem groups’ can avoid

single group dominance in public

spaces and help increase use and

make the space safer.

Community lead green space

management can address local needs

differently and possibly allow better

maintenance without increased

budget

Working with other communities or

groups with similar remits and aims

opens opportunities for

collaboration and knowledge

transfer

Maximising benefits: how could we make the most of gardens?

Some benefits can be maximised by taking some things into consideration when restoring/designing green space:

Educational Value

Signs explaining natural features and informing target groups (e.g. schools) about accessibility of the area

Mental Restorative Value

Natural Components have been found to increase the restorative potential of greenspaces. Provision of certain

elements is therefore important (e.g. large, sparsely distributed trees, meadow-like areas with flowers, water

features) (14, 15, 16, 17)

Provide sheltered places (but keep visibility/safety aspects in mind)

Play areas for children of different ages. To maximise benefits especially for younger children, a challenging, varied

environment is likely to increase development of balance, co-ordination and creativity.

Access to natural ‘wild’ areas provide different social and cultural benefits – e.g. inspiring children to more imaginative

play and so increasing their cognitive abilities,

Physical Health

Facilities supporting recreational activities – this can also mean use of land like detention basins where they are not

vegetated – e.g. as skate boarding areas, basketball courts, etc (depending on size and suitability).

High and low intensity activities should be encouraged – walking paths as well as exercise areas are therefore useful

64

References:

(1) Bhatti, M1. BOP Consulting. Green Spaces : The

Benefits for London Green Spaces : The Benefits for

London. Topical Interest Paper (2013).

(2) 2. Commission for Architecture and the Built

Environment. Decent parks? Decent behaviour?:

The link between the quality of parks and user

behaviour Contents Foreword. 1–17 (2005).

(3) 3. Alcock, I., White, M. P., Wheeler, B. W.,

Fleming, L. E. & Depledge, M. H. Longitudinal

effects on mental health of moving to greener and

less green urban areas. Environ. Sci. Technol. 48,

1247–55 (2014).

(4) 4. Lee, K. E., Williams, K. J. H., Sargent, L. D.,

Williams, N. S. G. & Johnson, K. A. 40-second

green roof views sustain attention: The role of

micro-breaks in attention restoration. J. Environ.

Psychol. 42, 182–189 (2015).

(5) 5. Woolley, H., Rose, S., Carmona, M. &

Freedman, J. The Value of Public Space. Exchange

Organizational Behavior Teaching Journal (2004).

(6) 6. Zelenski, J. M. & Nisbet, E. K. Happiness and

Feeling Connected: The Distinct Role of Nature

Relatedness. Environ. Behav. 46, 3–23 (2012).

(7) 7. Forest Research. Benefits of Green

Infrastructure. (2010).

(8) 8. Coombes, E., Jones, A. P. & Hillsdon, M. The

relationship of physical activity and overweight to

objectively measured green space accessibility and

use. Soc. Sci. Med. 70, 816–22 (2010).

(9) 9. Faculty of Public Health. Great Outdoors :


Space To Improve Wellbeing. 1–8 (2010).

(10) 10. Mitchell, R. & Popham, F. Greenspace, urbanity

and health: relationships in England. J. Epidemiol.

Community Health 61, 681–3 (2007).

(11) 11. van den Berg, M. et al. Health benefits of green

spaces in the living environment: A systematic

review of epidemiological studies. Urban For. Urban

Green. 14, 806–816 (2015).

(12) 12. Sunderland, T. Microeconomic Evidence for the

Benefits of Investment in the Environment - Review.

Natural England Research Reports, Number 033 2,

(2012).

(13) 13. Milligan, C. & Bingley, A. Restorative places or

scary spaces? The impact of woodland on the

mental well-being of young adults. Health Place 13,

799–811 (2007).

(14) 14. Nordh, H., Hartig, T., Hagerhall, C. M. & Fry,

G. Components of small urban parks that predict

the possibility for restoration. Urban For. Urban

Green. 8, 225–235 (2009).

(15) 15. White, M. et al. Blue space: The importance of

water for preference, affect, and restorativeness

ratings of natural and built scenes. J. Environ.

Psychol. 30, 482–493 (2010).

(16) 16. Völker, S. & Kistemann, T. ‘I’m always entirely

happy when I'm here!’ Urban blue enhancing

human health and well-being in Cologne and

Düsseldorf, Germany. Soc. Sci. Med. 78, 113–24

(2013).

(17) 17. Foley, R. & Kistemann, T. Blue space

geographies: Enabling health in place. Health Place

35, 157–65 (2015).

References and Guidance on Giving Access


Environment. Decent parks? Decent behaviour?:

The link between the quality of parks and user

behaviour Contents Foreword. 1–17 (2005).

(19) Crime and Public Safety. How Trees and

Vegetation Relate to Aggression and Violence (no

date). Available at:

https://depts.washington.edu/hhwb/datasheets/GC

GH_datasheet.Crime.pdf

(20) Kuo, F. E. and Sullivan, W. C. (2001) ‘Environment

and Crime in the Inner City: Does Vegetation

Reduce Crime?’, Environment and Behavior, 33(3),

pp. 343–367.

(21) McCormack, G. R., Rock, M., Toohey, A. M. and

Hignell, D. (2010) ‘Characteristics of urban parks

associated with park use and physical activity: a

review of qualitative research.’, Health & place,

16(4), pp. 712–26.

(22) National Audit Office (2006) ‘Enhancing Urban

Green Space.’, Report by the Comptroller and

Auditor General (London).

Weblinks:

(23) Forestry Commission – Accessibility of Green

Space http://www.forestry.gov.uk/fr/urgc-7eeggr

(24) Enhancing Urban Greenspace:

https://www.nao.org.uk/wp-

content/uploads/2006/03/0506935.pdf

(25) National Recreation and Parks Association, US.

Pocket Parks:

https://www.nrpa.org/uploadedFiles/nrpaorg/Grant

s_and_Partners/Recreation_and_Health/Resource

s/Issue_Briefs/Pocket-Parks.pdf

(26) PlacemakingResource – Maximising the use and

benefits of public parks and spaces:

http://www.placemakingresource.com/article/1364

326/advice-maximising-use-benefits-public-parks-

spaces/

http://www.forestry.gov.uk/fr/urgc-7eeggr




http://www.placemakingresource.com/article/1364326/advice-maximising-use-benefits-public-parks-spaces

