green lowimpact infrastructure for flood risk management &...

Oxford Consilium Ltd Flood risk & water storage in AlMadinah

Green lowimpact infrastructure forflood risk management & waterstorage in AlMadinah, KSA

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Figure 1. AlMadinah: the city and its surroundings.





Executive summaryOver the past twenty years, the city of AlMadinah has been facing an increasing number of extreme flood events. The naturally occurring floods, which previously fertilised wadi basins and irrigated nearby groves, are now increasingly devastating builtup areas. This is due to the rapid and large scale soil artificialisation over the past decades, compounded by climatic change. With the recently announced Haram AlSharif expansion and eastern AlMadinah housing projects, combined with projected demographic growth and urban sprawl, the situation is set to significantly worsen in the years and decades to come, unless there are major changes in the management of stormwater.

This study sheds light on how authorities can efficiently protect AlMadinah’s population, key infrastructure and economic prosperity via a mix of lowimpact stormwater harvesting, prefiltering and storage, while recharging AlMadinah’s depleted aquifer resources.

The strategy to do so is underpinned by principles of:

● Efficiency in protection of the populations and built environment.● Cost efficiency of the completed program.

This study introduces three groups of lowimpact solutions, specially redesigned for AlMadinah’s area:

● Artificial Aquifer Recharge (AAR), with flashflood control and prefiltration by gabions, for the recharge of aquifers with large quantities of stormwater in strategic areas.

● Urban lowimpact infrastructure, located in the lowlying places of the inner city.● Basic and advanced rain gardens (e.g., with biopori holes and water reservoirs), to further protect the built environment and infrastructures of the inner city and key roads.

These solutions are deliberately labelled ‘lowimpact’ because they do not require the existing storm water system to be redesigned or reconstructed. Instead, lowimpact solutions, now recommended by the European Environmental Agency and the United States Environmental Protection Agency, provide an efficient addition to the existing storm water network.

Since no GCC country has ever introduced these green solutions, AlMadinah and the Kingdom could become regional leaders in the use of lowimpact water solutions. Finally, given the Al Selouly Group’s experience in landscaping, and Oxford Consilium’s expertise in water management and risk management in the Arab world and beyond, the solutions above can be implemented in an effective and costefficient manner by a joint venture aimed at enhancing AlMadinah’s flood management and water security, inshaAllah.





ContentsExecutive summary

1. Introduction

2. Observations and analysis

2.1. AlMadinah: current situation and critical perspectives

The lost resource

2.2. Strategy: Lowimpact solutions and water storage

Aims

The strategy

Strategic orientation

3. The technology mix, adapted to AlMadinah

3.1. Gabions and AAR (Artificial Aquifer Recharge)

3.2. Urban lowimpact infrastructure

3.3. Rain gardens

3.4. Key considerations

4. Conclusions and recommendations

A. Appendix

References





Authors and contact● Dr Laurent Abdullah Lambert*. DPhil (Oxon), Europaeum Ad Hoc Research Director for Environmental Workshops. Oxford Consilium Director, Water R&D.● Dr Raveem Ismail. DPhil, MSc, MPhys (Oxon), MInstP. Oxford Consilium Chief Analyst.● Kristof von CsefelvayBartal. MSc, MA (Oxon), FRSA, MCIArb, AMRI. Oxford Consilium Chief Operating Officer.

* Primary contact. [email protected].

Document informationVersion Notes Date

0.1 Begun. 07/02/2014

0.2 Revised and expanded. 23/02/2014

0.3 For circulation with Sheikh Al Selouly. 01/03/2014

Typeset: 1st March, 2014.

Typesetting system: Google.




mailto:[email protected]


1. IntroductionOver the past ten years, floods in Western Saudi Arabia have had devastating consequences: with hundreds of victims, well over 25 billion dollars of direct material damage, and significant impact on local communities and the overall economy.

After analysing the current situation, trends and forecasts for AlMadinah, this study will propose the first elements of an efficient strategy for the AlMadinah area (including its key peripheral infrastructure), and introduce three main types of technological solution. Combined, these would serve to significantly mitigate the flood risks, replenish underground water resources in and around AlMadinah, provide local employment, and effect green technology transfer to Saudi industry.





2. Observations and analysis

2.1. AlMadinah: current situation and critical perspectives

Flooding is an old and recognised phenomenon in Saudi Arabia, but the devastating characteristics of the flooding since the late 1990s can be attributed to three main causes in AlMadinah:

● Madinah lies in a natural depression between mountains, hills and wadi valleys.● Madinah was transformed from a small city in relative ecological equilibrium with its surroundings into a large modern metropolis with a rapidly growing urban sprawl.

Attribute Value Notes

Name AlMadinah Officially alMadīnah alMunawwarah.

Location 24° 28’ N36° 30’ E

Capital of AlMadinah Province.Located: Hejaz region, western SaudiArabia.

Geography Elevation: 608 m Soil: basalt.Surrounding hills: volcanic ash.Lower than surrounding terrain.120 miles (190 km) from the Red Sea.

Climate Hot desert Koppen classification: BWh.40°C day / 28° night.Limited precipitation annually, butviolent storms.

Population (2010) 1,180,770 Circa 1918: population of 10,000inhabitants.→ Over 10,000% demographic growth inless than a century.

Current storm water mitigation system

(Grey) drainagecanalisation,using gravity

Decreasingly capable of evacuatingstorm water and wadi floods because ofthe city’s growth and its elevatedsurroundings.

Table 1. AlMadinah: key information.

The rare but violent storm events produce vast quantities of water channelled by wadis near the city of AlMadinah (Photo 1) and even across the city (Photo 2).





Photo 1. Violent rain events create largelyuncontrolled wadis that threaten AlMadinahyearly (January 2014). Source: SPA, Jan 2014.

Photo 2. Storm water flooding in AlMadinah’sbuiltup area (January 2014). Source: ArabNews, Jan 2014.

Photo 3. Flood damage due to insufficientdrainage infrastructure (January 2014). Source:Arab News, Jan 2014.





The lost resource

Beyond flooding risk, uncontrolled wadis in AlMadinah’s area represent a large amount of precious fresh water resource, currently significantly underutilised. Most of AlMadinah’s wadi resources, representing well over one hundred million cubic metres of freshwater at least once a year (visible in the NASA satellite imagery in Figure 2), will be lost in evaporation, while the rest ends up into the Red Sea, before being desalinated again for the Kingdom’s water supply .1

Figure 2. On the satellite imagery, flood water gushes through the deep valleys around AlMadinah, Saudi Arabia, resembling blue veins amidst the marbled desert landscape. The Moderate Resolution Imaging Spectroradiometer (MODIS), flying on NASA’s Terra satellite, captured the top image of the floods on January 24, 2005, two days after the storm. In both images, streaks of green plants line the Wadi al Hamd, which flows by the city from the northwest.

Source: NASA, 2005, created by Jesse Allen, Earth Observatory. Instrument: Terra MODIS.NASA2005

1 Yanbu’s large desalination plant desalinates 128,000 m3/day of sea water to provide AlMadinah (190 km away and 608 m above sea level) via pipelines. The pipes have to circumnavigate the hills and mountains of Hejaz, and requires pumping to reach AlMadinah’s altitude. The total infrastructure, maintenance and energy costs (in crude oil, gas and electricity) of this wasteful water management system remains is beyond the scope of this current work, but is undoubtedly significant.





2.2. Strategy: Lowimpact solutions and water storage

Aims

● High efficiency in flood risk management.● Cost efficiency.

The strategy

In particular, to focus on the inner city within the two RRs (Ring Roads) and the most important road segments (based on economic and strategic criteria). These should be secured from the main sources of storm water external to the second RR.

The external layers of the city would be secured by controlling and storing underground the excess rain and flood water from the main wadis.

Strategic orientation

● Providing adapted infrastructure to key segments of selected wadis to control, pretreat and store storm water. Key segments of wadis most particularly considered:○ Wadi AlAqeeq (various points between 2nd and 3rd RRs).○ Wadi AlHamd (along Uthman Bin Affan Rd and AlBayda Rd).○ Waadi Qunaah (just before it joins Wadi AlAqeeq).○ The storm water drainage canal (between 2nd and 3rd RRs).

● Protecting the inner city and key roads from the sources of torrential waters located outside the 2nd RR. Key roads considered for preemptive work:○ King Abdullah Road (2nd RR).○ Airport Road.○ Jami’at Road.○ Tabuk Road (National 15).○ AlBayda Road.○ Uthman Bin Affan Road.○ National 60.○ AlSalam Road.○ King Khaled Road (3rd RR).

● Controlling and storing storm water within the 1st and 2nd RRs with urban lowimpact infrastructure:○ A selection of lowlying places within the 1st and 2nd RRs.





2.3. The case for green storm water solutions in AlMadinah

Theoretically, conventional stormwater infrastructure drains the water and sends it away from the built environment. In rapidly expanding cities, the reality is that this water often finds its way toward lowlying places such as wadis and other streams, actually increasing peak flows and thus, flood risk. Eventually, this process exacerbates the destructive effect of all stormwater not successfully evacuated, as has repeatedly been seen in Jeddah.

Photo 4. The 2009Jeddah floods.Uncontrolled storm watertransformed roads intorivers.

Source: AlArabiyaarchives.

The 2009 Jeddah floods illustrated the incapacity for canalisation to alone control large amounts of storm water, and the structural impossibility for evacuating large volumes far and fast enough away from the built environment. In the meanwhile, Jeddah’s underground water reserves remain severely depleted, and Jeddah relies heavily on expensive desalination for most of its water needs.

The conventional, concreteintensive “grey” infrastructure, conceived in late 19th Century Europe, generally imply significant construction and maintenance cost, with long timelines and business models adapted to highly industrialised cities. The heavy cost of canalisation is then split across multiple taxpayers and water users. This system is therefore not technologically, environmentally nor economically adapted to the fastsprawling Saudi cities, where no taxation regime recovers the money invested, and where housing units are spread over a large territory.Beyond their long construction timelines and heavy costs, extended networks of canals do not fit the reality of widespread housing units, as in Saudi Arabia, a country with the fourth lowest density of population in the world.





Photo 5. Water Pipelines in the Makkah region.

Source: Arab News.

Green infrastructure, on the other hand, can mitigate flood risk by slowing, reducing and storing a significant amount of storm water at its source, or nearby. Because of the limited heavy work needed in the built environment (water is stored, but not transported through extended canalisation) it is also known as “lowimpact development”.

Lowimpact solutions are now recommended to both municipal and private actors by the competent authorities in Australia, the USA and European Union for cost efficiency, rapid adaptability and environmental advantages.





3. The technology mix, adapted to AlMadinah

Below is a short description of the specifically designed mix of low impact (green) infrastructure solutions for storm water control, management and storage, in order of descending work intensity.

3.1. Gabions and AAR (Artificial Aquifer Recharge)

Control and prefiltration by gabions will allow for the recharge of superficial and deep aquifers with large quantities of storm water.

Rainwater control, prefiltering and storage with gabions is the art of slowing down stormwater and letting it infiltrate locally, rather than channeling water too quickly by letting it run off the land (leading to flooding downstream) or stoppage by a dam (leading to massive evaporation and soil salinisation). Gabions treat rainwater as an asset rather than a problem. It can then be absorbed in large quantities by a well placed behind the gabion, to recharge the upper aquifers or the deeper aquifers, depending on the hydrogeology.

Photo 6. A gabion dam in a large wadi valley,AlJaffa, Libya.

Water is slowed down (but not stopped) by the gabion structure, subsequently infiltrating underground. The watercarried soil material (silt, stones, organic matter, etc.) remain behind the structure and form, year after year, a fertile ground for annual crops within the flood plain, thus producing a virtuous cycle of desert reclamation.

Photo 7. A very small community gabion for upper aquifer recharge, India.





3.2. Urban lowimpact infrastructure

These aim to collect and store stormwater underground, in the lowlying places of the city.

Rainwater is received, prefiltrated with mulch, geotextiles and granular soils, after which a gravity reservoir stores the water underground. This water can then be reused for greening, or be collected for full treatment. Such lowimpact infrastructure (not requiring canalis to be dug throughout the city) can rapidly be installed on parking spaces, large pavements or other underutilised urban space. The efficiency arises not from each unit’s capacity, but from their collective action, number and strategic positioning within the built environment.

3.3. Rain gardens

These are basic/advanced infiltration units which serve to further protect the built environment and infrastructure, while replenishing upper aquifers.

By retaining rainfall during storms, rain gardens reduce stormwater discharge. Lower discharge volumes translate into reduced flooding risks. By multiplying the number of these small rain gardens, the urban environment remains able to cope with all local rain events.




http://www.google.com/url?q=http%3A%2F%2Fwww.burnsville.org%2FDocumentView.aspx%3FDID%3D450&sa=D&sntz=1&usg=AFQjCNGm8lxsQXfJtrJ0y1J5LicmkqfoWg

http://www.google.com/url?q=http%3A%2F%2Fwww.kingcounty.gov%2Fenvironment%2Fwtd%2FConstruction%2FSeattle%2FBartonCSO-GSI.aspx&sa=D&sntz=1&usg=AFQjCNHMlGKHfxCFgyfaoHC6SJyu_IqYyw


Specific designs can be developed to be able to cope with rapidly increasing stormwater quantities.

Photo 8. A rain garden built on two former

parking spaces, processing excess water (USA).

It should be noted that uncontrolled storm water, crossing over built areas, can deliver many pollutants to wadis and aquifers. This could include pathogens, sediments, oil fuels and heavy metals from roads, factories and parking facilities. Water collected in rain gardens is pretreated by layers of mulch, granular soils and geotextiles. The water can later be used for outdoor irrigation, and thus reduces municipal water use.




http://www.google.com/url?q=http%3A%2F%2Fwww.coloadaptationprofile.org%2Findex.php%3Foption%3Dcom_docman%26task%3Ddoc_details%26gid%3D99%26Itemid%3D75&sa=D&sntz=1&usg=AFQjCNHvAw1MMMIRAIres-YIcmym3_wDQQ


Photo 9 (annotated). Example of places in AlMadinah where small rain gardens could drain storm water.

Storm water collected can be subsequently used as a reserve for the rain garden’s plants during most of the

year. Plants should be selected based on their limited water needs, the depth of their root system, and

sudden absorption capacities (which tends to be fairly high with local plants), limited need of maintenance,

and aesthetic quality.





3.4. Key considerations

The individual technologies mentioned in previous sections have been successfully tested over the past ten to twenty years in various conditions. The European Environmental Agency and the United States Environmental Protection Agency now support the implementation of green technologies for storm water management by their municipalities, due to their efficiency and costeffectiveness .2

As regards their appropriateness here:

● All three solutions are efficient in arid environments, with most originating from Australia and some

dry US states.

● They can be precisely calibrated for the local specificities of AlMadinah (its precipitation regime,

topography, geology, water chemistry, etc.).

● All control stormwater 'on the spot', and pretreat and store water underground for later recovery.

Increasing underground freshwater resources is a particularly costefficient alternative to lengthy

canalisation, desalination and/or artificial strategic reserves. The latter cost SR 1 billion for a single

reserve facility of capacity of 1.3 million cubic meters storage in Makkah , and SR 1.5 billion per 3

reservoir in Jeddah for 1.5 million cubic meters (the city plans to have four) . Meanwhile, the 4

majority of these cities’ aquifers (i.e., natural underground reservoirs) remain largely empty .5

● Private and public cost savings. According to the US Environmental Protection Agency : “when 6

stormwater management systems are based on green infrastructure rather than gray

infrastructure (canalisation networks), developers often experience lower capital costs.

These savings derive from lower costs for site grading, paving, ... and smaller or eliminated

piping and detention facilities.”.

2 The United States Environmental Protection Agency website states: “... green infrastructure reduces and treats stormwater at its source while delivering many other environmental, social, and economic benefits. ... Green infrastructure is a costeffective and resilient approach to our water infrastructure needs that provides many community benefits.”.

3 Strategic water storage facility to cost SR1bn, Arab News, Monday 24 February 2014, available at: www.arabnews.com/news/530411.4 Jeddah’s houses to be linked to main drainage network in 2011, Saudi Gazette, available at: www.saudigazette.com.sa/index.cfm?method=home.PrintContent&action=Print&contentID=0000000084824.

5 In some places, forms of land subsidence (collapse) have been noted throughout the Hejaz region due to antropogenic water level decline in aquifers (Bankher, AlHarthi, 1999). The use of motor pumps for agricultural purposes leads also to such geologic hazards in AlMadinah’s surrounding area.

6 Official statement from the US EPA. See http://water.epa.gov/infrastructure/greeninfrastructure/gi_why.cfm.




http://www.google.com/url?q=http%3A%2F%2Fwww.epa.gov%2Fowow%2FNPS%2Flid%2Fcosts07%2Fdocuments%2Freducingstormwatercosts.pdf&sa=D&sntz=1&usg=AFQjCNHeu5tctqT_wMSG1wPJ6AiPhOuLuQ

http://www.google.com/url?q=http%3A%2F%2Fwww.arabnews.com%2Fnews%2F530411&sa=D&sntz=1&usg=AFQjCNFkdinCfByPlesUHegShTqYAb5bNw

http://www.google.com/url?q=http%3A%2F%2Fwww.saudigazette.com.sa%2Findex.cfm%3Fmethod%3Dhome.PrintContent%26action%3DPrint%26contentID%3D0000000084824&sa=D&sntz=1&usg=AFQjCNE8dAshXNY_WsMTyKg8s2TAfLyqkQ

http://www.google.com/url?q=http%3A%2F%2Fwater.epa.gov%2Finfrastructure%2Fgreeninfrastructure%2Fgi_why.cfm&sa=D&sntz=1&usg=AFQjCNHCMTuy35gl12mWSyL_4U6-YuaOiA


● Energy savings. Treating and moving water throughout a city’s water network consumes a lot of

energy. By reducing storm water inflow into sewer systems, recharging aquifers, and conserving

water, green infrastructure can significantly reduce the municipality’s energy use.

● Increased vegetation and improved air quality. Ground level ozone or smog is created when

nitrogen oxides (NOx) and volatile organic compounds (VOCs) interact in the presence of heat

and sunlight. Smog conditions are usually worst in summer and can lead to respiratory health

problems. The increased vegetation due to these lowimpact solutions can reduce groundlevel

ozone by reducing air temperatures, reducing power plant emissions associated with air

conditioning, and removing a portion of air pollutants.





4. Conclusions and recommendationsThere is increasingly a critical flood risk in AlMadinah’s builtup area, which could eventually resemble

Jeddah’s devastating flood events within a decade, due to the increased footprint of the builtup

environment and observed climatic variation.

This study has shed light on how authorities can efficiently protect AlMadinah’s population, key

infrastructure and economic prosperity via a mix of lowimpact stormwater harvesting, prefiltering and

storage, while recharging AlMadinah’s depleted aquifer resources.

A welldesigned mix of lowimpact solutions provides an efficient, costeffective addition to the existing

storm water mitigation system, and can safely store the water for later recovery. These solutions would

also provide some local employment.

Given the Al Selouly Group’s record of landscaping in the Kingdom, and the significant consulting expertise

present in Oxford Consilium on water and risk management, the three abovementioned technological

solutions can be implemented in an effective and costefficient manner by a joint venture. The results would

sharply enhance the flood management and water security of AlMadinah, transfer green technological

expertise to the Saudi partners of the joint venture, and support the sustainable development of the Holy

City, inshaAllah.





A. Appendix

Figure A.1. WMO data (below) plotted to show average, monthly maximum and daily maximum precipitation.

Figure A.2. Location of stationused to gather measurements forFigure A.1.





Raw WMO station data used in figures above: Station Name: MADINAH WMO Station Number: 40430National I.D. Number: Country: SAUDI ARABIA WMO Region: REGION II ASIA Latitude: 24d 33m N Longitude: 039d 42m E Elevation: 636 m

In the following tables, byr = beginning year of normals or extremes data period eyr = ending year of normals or extremes data period NA = Not Applicable, data not submitted or not computed * = value > 0 but < units resolution AnnNCDC = annual value computed by NCDC from monthly values provided by Members==========================================================The normals data and climate variable descriptions arepresented in these tables as provided by the WMO Membercountry.==========================================================

Element 06: Precipitation (mm)MEANMLY (Statistic 15): Mean Monthly ValueMAX_MLY (Statistic 26): Maximum Monthly ValueYRMXMLY (Statistic 27): Year of Occurrence of Maximum Monthly Value byr: 1961 1961 1961 eyr: 1990 1990 1990Statistic: MEANMLY MAX_MLY YRMXMLY Month Jan 8.0 70.0 1969 Feb 1.2 9.0 1966 Mar 8.3 47.0 1971 Apr 11.9 79.0 1982 May 4.6 39.6 1982 Jun .4 6.8 1983 Jul .2 6.0 1978 Aug .3 4.9 1979 Sep .1 0.6 1984 Oct 1.1 12.8 1982 Nov 9.2 62.0 1984 Dec 3.8 21.1 1989 Annual NA NA NA AnnNCDC 49.1 NA NA

Element 08: Maximum 24Hour Precipitation (mm)MAX_VAL (Statistic 04): Maximum ValueDATEMAX (Statistic 12): Date (Year/Day) of Occurrence of Maximum Daily Value byr: 1961 1961 eyr: 1990 1990Statistic: MAX_VAL DATEMAX Month Jan 70.0 196904 Feb 7.7 198624 Mar 38.0 197127 Apr 38.0 197112 May 20.7 198210 Jun 4.5 198301 Jul 6.0 197819 Aug 3.6 197927 Sep 0.6 198413 Oct 7.0 198217 Nov 43.9 198425 Dec 14.4 197404 Annual NA NA AnnNCDC NA NA





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Arab News (Facebook page album). Rain and flood in Madinah. URL: https://www.facebook.com/media/set/?set=a.10152227176352125.1073741891.10250877124&type=1#, last visited: 25/02/2014. 28/01/2014.

BBC. Flooding kills 29 in Saudi Arabia. URL: http://news.bbc.co.uk/1/hi/world/middle_east/4205373.stm, last visited: 23/02/2014. 25/01/2005.

Dawod, Gomaa M and Mirza, Meraj N and AlGhamdi, Khalid A. GISbased estimation of flood hazard impacts on road network in Makkah city, Saudi Arabia. Environmental Earth Sciences. 2012.

NASA. Floods in Saudi Arabia. URL: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=14554, last visited: 23/02/2014.

NOAA. [TITLE]. URL: ftp://ftp.atdd.noaa.gov/pub/GCOS/WMONormals/RAII/SD/40430.TXT. Last visited: 18/02/2014.

Subyani, Ali M and AlAhmadi, Fahd S. RainfallRunoff Modeling In The AlMadinah Area Of Western Saudi Arabia. Journal Of Environmental Hydrology. Vol. 19, Paper 1. 01/2011.

United States Environmental Protection Agency. [TITLE]. URL: [URL]. Last visited: [DAY]/02/2014.

Bankher, K.A., Abbas A. AlHarthi (1999) Earth Fissuring and Land Subsidence in Western Saudi Arabia, Natural Hazards, 20: 2142, 1999.




http://www.google.com/url?q=http%3A%2F%2Fwww.arabnews.com%2Fnews%2F517141&sa=D&sntz=1&usg=AFQjCNG_3VjNnpmo0nYl9z7uVnfKSVu2cw

https://www.google.com/url?q=https%3A%2F%2Fwww.facebook.com%2Fmedia%2Fset%2F%3Fset%3Da.10152227176352125.1073741891.10250877124%26type%3D1%23&sa=D&sntz=1&usg=AFQjCNEC0s6QtFcCotyEGdhfkB6o0ywUmg

https://www.google.com/url?q=https%3A%2F%2Fwww.facebook.com%2Fmedia%2Fset%2F%3Fset%3Da.10152227176352125.1073741891.10250877124%26type%3D1%23&sa=D&sntz=1&usg=AFQjCNEC0s6QtFcCotyEGdhfkB6o0ywUmg

http://www.google.com/url?q=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fworld%2Fmiddle_east%2F4205373.stm&sa=D&sntz=1&usg=AFQjCNENGaFy8_p0qklonFAoU2Mn464hKw

http://www.google.com/url?q=http%3A%2F%2Fearthobservatory.nasa.gov%2FNaturalHazards%2Fview.php%3Fid%3D14554&sa=D&sntz=1&usg=AFQjCNE5HpopBnB76DakLmpWb-i6yzs_Dg

http://www.google.com/url?q=http%3A%2F%2Fftp.atdd.noaa.gov%2Fpub%2FGCOS%2FWMO-Normals%2FRA-II%2FSD%2F40430.TXT&sa=D&sntz=1&usg=AFQjCNECWnQXvL3PqMRDaK6JAzIKQPvE9g


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