Considerations for Improving Water

Use in the Landscape

TRICITIES LANDSCAPE SEMINARAPRIL 14TH, 2015

MAUREEN THIESSENCOMMERCIAL ORNAMENTAL AREA SPECIALIST

TENNESSEE STATE UNIVERSITY, UNIVERSITY OF TENNESSEE

Purpose of irrigation system

To deliver adequate water to plantings such that manual

methods are reduced as much as possible.

Objectives

Identify problems associated with improper irrigation management

Understand landscape and environmental elements that should be considered in irrigation design

Learn how to account for those elements in irrigation design using appropriate equipment and scheduling

Reasons to be conscientious about water

Plant health, disease

Root Establishment

Water availability

Environmental conservation

Maintain a professional look

Photo: Savelandscapewater.org

Photo: Forester University

Photo: Turfdiseases.org

Photo: University of Florida

Cost of Municipal Water

Alliance for Water Works

27,154 gallons

Cost of Municipal Water

Alliance for Water Works

6,788 gallons

Cost of Municipal Water

One inch of water applied over an acre is 27,154 gallons

One-quarter acre-inch = 6,788 gallons

Within City: $3.47/1000gal + base ($3.47 x 6.788gal) + ($4.46)

= $28.00 per inch of applied

water

Alliance for Water Works

Outside City:$6.94/1000gal + base

($6.94 x 6.788gal + $8.92)$56.03 per inch of applied

water

Johnson City Water Rates (not including sewer)

Scheduling considerationsMother Nature’s Resources Plant type

Some plants require more than others Soil

Infiltration - Different soil types absorb water at differing rates

Water holding capacity - Some soils hold more water than others

Topography Weather

Estimating plant requirements Do not water entire landscape according to one

plant type’s needs Separate zones with differing water

requirements Consider rooting depth Minimum – separate beds and turf

Photo: Alliance for water efficiency Photo: LSU AgCenter

Turfgrass Area of the landscape with highest

density of photosynthesizing tissue - highest evaporative demand.

Up to 1.5 inches a week More frequent watering

Ornamental – trees, shrub beds

Do not need as much water as turf Hardier than turf and annuals Deep rooting Fewer applications, higher volume

Pictures: Ball Seed

Ornamental – annual beds Generally shallower root systems, dry

out more quickly Tender foliage Water more often with less volume

Pictures: Ball Seed

Water Requirements of PlantsDry Soils Box Elder Redbud Smoketree Hawthorn Walnut Pines Quince Junipers Photinia Spirea

Wet Soils River Birch Silver Maple White Ash Magnolia Sycamore Bald Cypress Japanese Cedar Forsythia Hydrangea Beautyberry

Other considerations

New turf will need more frequent, smaller applications of water Reduce erosion, but supply adequate water

to young roots Gradually increase time between

irrigations to encourage deeper rooting. New ornamental plantings should be

watered-in, but allowed periods of dryness to encourage rooting.

Scheduling considerationsMother Nature’s Resources

Plant type Some plants require more than

others Soil

Infiltration - Different soil types absorb water at differing rates

Water holding capacity - Some soils hold more water than others

Topography Weather

Why is the soil important? Soil types hold different amounts of water

and for different amounts of time.Water Holding Capacity (WHC) or Field

Capacity (FC) Soil types absorb water at different rates

Infiltration Rate (IR) Affects how much and how often you apply

water Texture, structure, and topography

Texture – the particles Three textural classes

– sand, silt, and clay

Proportions of each class determines ability and length of time to absorb and hold water

Sand Silt Clay

Loose, gritty Very permeable Easily leached

Low WHCHigh porosity

CrumblyLess permeableDownward and

lateral movement similar

Higher WHCMedium porosity

Sticky, moldableLeast permeable

Susceptible to runoff

Higher WHCLow porosity

http://i3.photobucket.com/albums/y51/wilddog_202/Clayafteryearsoforganicmatter.jpgPhoto: https://ncptt.nps.govPhoto: Salinitymanagement.org

Soil Water-Holding Capacity

Ron Sheffield, LSU AgCenter

COARSE >>>>>>>>>>>>>>>>>>>>>>>>>>FINE

Maximum water it can hold

Moisture content at wilting (how tightly water is held.

Water-Holding Capacity and Retention

Hillel. Introduction to Environmental Soil Physics, 2004.

Infiltration

Hillel. Introduction to Environmental Soil Physics, 2004.

Soil Texture and Infiltration

Clays have slow infiltration rates but stay wet longer

Sands have quick infiltration rates, and dry out more quickly

Application rate should not exceed the rate of infiltration

Structure – how the particles fit together

Aggregation increases porosity (O2 and H20) and infiltration

Often altered by construction Severe compaction Lack of OM and aggregation Increased runoff, limited

rooting Tillage, OM amending, and

mounding, adjust irrigation to apply more slowly.

Photo: Colorado State University

Scheduling considerationsMother Nature’s Resources

Plant type Some plants require more than

others Soil

Infiltration - Different soil types absorb water at differing rates

Water holding capacity - Some soils hold more water than others

Topography Weather

Landscape Topography Slopes lower infiltration rate

Increased runoff Lower application rate or divide

total irrigation into multiple applications

Slopes can cause different areas of the landscape to be wetter/drier than others.

Put low lying areas on different zone

LandscapingNetwork.com

Slope and Soil Texture

Rainbird ® Irrigation Design Manual

Scheduling considerationsMother Nature’s Resources

Plant type Some plants require more than

others Soil

Infiltration - Different soil types absorb water at differing rates

Water holding capacity - Some soils hold more water than others

Topography Weather

Weather Irrigation needs affected by

precipitation, temperature, sunlight Evapotranspiration – water loss from

landscape to the atmosphere through evaporation and plant transpiration

Consider season Make sure your irrigation program

changes throughout the year Differences in rainfall, temperature,

plant dormancy

WeatherAverage Annual PrecipitationTN Climatological Service

Weather

Scheduling considerationsMother Nature’s Resources

Plant type Some plants require more than

others Soil

Infiltration - Different soil types absorb water at differing rates

Water holding capacity - Some soils hold more water than others

Topography Weather

Design The efficiency of an irrigation

system is limited by its design. Proper zoning Proper output

Application rate awareness

Hydrozones Use zones to separate areas of different

water need, as well as deal with limited available pressure.

Zones should take into account the plant type needs and the soil characteristics

Separate areas that tend to stay dry/wet If you water it differently, tap it differently! Make sure design pressure of each zone

doesn’t exceed what is available.

Rainbird® Irrigation Basics Manual p.16

Delivery Methods

Things to always keep in mindRadius of throwOperating pressureFlow ratePrecipitation rate or application

rate

Sprinklers Impact, rotor, gear-driven High flow (2-16gpm), high pressure requirements (30-

80psi) Bigger radius of coverage (65ft) Single stream or multistream Generally used on large, open turf areas

http://recreational-turf.wikispaces.com/file/view/40.jpg/186231979/40.jpg

Rainbird®

Sprayers Medium flow (1-5gpm), medium pressure Smaller area of coverage (10-30 feet) Come in variety of spray shapes

http://www.hunterindustries.com/irrigation-product/spray-bodies/ps-ultra#

Drip Irrigation Most precise placement of water - applies directly to root

zone Much lower flow rate (gallons per hour) and pressure

requirements (10 – 50psi)

http://www.hunterindustries.com/sites/default/files/styles/product_header/public/580x325_product_slider_00-pse-7.jpg?itok=v1Tt31aM

Drip Irrigation Consists of tubing – emitter – microsprayer design to

deliver water to individual plants. Least loss to evaporation Higher installation cost, more likely to clog, but most

efficient Keeps foliage from getting wet

http://www.hunterindustries.com/irrigation-product/micro-irrigation/micro-sprays#

https://rainbird.com/landscape/products/dripEmission/XeriBugEmitters.htm

Drip Irrigation

Filters and pressure regulators especially important

Some filters are pressure – regulating Kits are available with included valve, filter,

pressure regulator components

Precipitation Rate Proper timing needs to take into account precipitation

rate For one given flow rate:

0.24” per hour

0.32” per hour

0.48” per hour

0.96” per hour

1X 4X2X1.3X

Know your precipitation rate Rotating heads

usually do not adjust flow rate for variable arcs

Adjust GPM in your calculations accordingly

Always check performance charts

Know your precipitation rate Matched Precipitation rate

(MPR) nozzles usually available as “series”

Can also be variable / adjustable arc nozzles

GPM is adjusted according to arc to keep precipitation rate constant.

Common in spray bodies Always check performance

charts

Know your zone precipitation rate…

Check performance chart data BE CAREFUL – rotor performance data often based on

half circle operation Therefore, divide precipitation by 2 if using 360˚ rotation

S

S

S

𝑃𝑅=96.3𝑋 𝐺𝑃𝑀

𝑆2𝑃𝑅=

96.3𝑋 𝐺𝑃𝑀0.866 𝑋 𝑆2

Know Your Precipitation Rate…

AWS Irrigation

Controllers Need to maintain flexibility You/client are the irrigation manager, not

the clock Consider user-friendliness, especially for

homeowners

Weather and Location

Sensors Rain Soil Moisture

More sophisticated scheduling exists using ET data along with other weather parameters Generally require weather station Example: Hunter® ET System

When is the best time?

EfficiencyMidday irrigation offers cooling,

but is the most inefficient time of day due to evaporative loss

Nighttime irrigation has greatest chance for disease development

Early morning hours (5-9) allow time for foliage to dry

How Often?

Plant ageHow established are the roots?

Consider seasonDo not use one irrigation

program for entire yearDifferences in rainfall,

temperature, plant dormancy

How Much? Season

Imagine cost of 1” per week for 52 weeks per year…

Rooting depth and establishment

Canopy Cover How dense is the canopy, or

leaf area, of the area to be irrigated?

Turf vs. woody vs. annual New plantings vs. established

Remember Design the system so water is placed

uniformly and efficiently Remember to consider plant type and

establishment, soil type and condition, sloping, shading, and time of day.

Observe irrigation system performance after installation and routinely, adjust accordingly

Explore available technology that accounts for rain and existent soil moisture.

Reference Material

“Fertilization and Management of Home Lawns.” Publication 1038. University of Tennessee Agricultural Extension Service. <https://extension.tennessee.edu/publications/Documents/PB1038.pdf>.

Wells, Wayne. “Establish and Manage Your Home Lawn.” Publication 1322 Mississippi State University Cooperative Extension. http://msucares.com/pubs/publications/p1322.pdf.

“Growing Tree Fruits Successfully.” Online Presentation. Oregon State University Extension Service. http://extension.oregonstate.edu/lane/sites/default/files/documents/tree_fruit.tf_specialists.pdf.

Stein, Larry, and Welsh, Doug. “Efficient Use of Water in the Garden Landscape.” Texas A&M AgrilLife Extension. http://aggie-horticulture.tamu.edu/earthkind/drought/efficient-use-of-water-in-the-garden-and-landscape/.

Sheffield, Ron, and Thomas, Dan. “Irrigation Basics for Landscape Contractors.” Irrigation Contractor Class Manual. LSU AgCenter.

Sheffield, Ron. “Irrigation Basics of Irrigation Contractors.” LSU AgCenter. http://www.lsuagcenter.com/en/our_offices/departments/Biological_Ag_Engineering/Features/Extension/Agriculture_and_Environment/Irrigation/Irrigation-Basics-for-Irrigation-Landscape-Contractors.htm>.

Smith, Bryan W. “Irrigation.” Series on Landscape Irrigation Basics. Clemson University Extension. http://www.clemson.edu/extension/hgic/plants/other/irrigation/.

Questions?Contact Me:

Maureen ThiessenArea Specialist

Commercial Ornamentals, Eastern Regionmthiesse@utk.edu423 – 798 – 1710

Greeneville County Extension Office

Thank You!