Water Conservation Strategies for Commercial Landscaping

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Water Conservation Strategies for Commercial
Landscaping
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Increasing demand
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Metro Atlanta water use

• Single Family residential water consumption
  191 MGD to 280 MGD (149 GPCD)
• Outdoor water consumption 38 MGD to 56 MGD

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Regional Limitations to Water Resources

• 98 of Atlantas water needs are supplied by
  surface water sources
• 80 of surface water is supplied by the
  Chattahoochee
• Atlantas location at the headwaters limits the
  supply
• Bedrock limits groundwater sources
• Increasing demand 1,000,000 residents in 10
  years SOURCE ARC

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3 Steps for Outdoor Water Conservation

• Minimize water demand

• Meet demand with non-potable water

• Deliver water efficiently

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Minimize Water Demand
Use regionally native or Drought-tolerant
non-invasive species
Minimize the use of turf
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Minimize Water Demand
Keep stormwater runoff on-site to nourish the
landscape
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Minimize Water Demand
Protect and restore healthy soil.
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Meet Demand with Non-potable Water

• Benefits of Rainwater Harvesting
• Rainwater is free helps to reduce utility bills
• Can eliminate costly infrastructure
• Not subject to watering restrictions
• Eliminates the need for water softeners if used
  indoors
• Rainwater is the most pure water (chemical free)
  to use on plants, vegetables, etc.
• Reduces runoff to storm drains
• Entire system costs range from .75/gallon to
  2/gallon with a payback period of less than ten
  years (NCSU).
• Important part of an overall strategy to conserve
  water resources

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Meet Demand with Non-potable Water

• History of Rainwater Harvesting
• Rainwater harvesting is an ancient technique
  dating back as far as 4,000 years ago.
• Still widespread in India, Australia, the
  Caribbean and other regions with poor public
  infrastructure and dry climates.
• Enjoying a resurgence in the US, partly due to
  superior water quality and partly due to the
  desire to reduce consumption an estimated
  100,000 systems are in use.
• Currently, there are no national standards
  governing rainwater harvesting.
• However, rainwater harvesting is currently
  mandated for new construction in Bermuda, US
  Virgin Islands and other Caribbean islands.
• Incentives are in place to offset costs in Texas
  (maybe in the southeast soon?)
• Simplest systems are land-based and may consist
  of earthen berms and reservoirs.
• More complex systems take many forms

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Memorial Garden _at_ the SLC (Photo courtesy of
Kevin Kirsche, University Architects)
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Meet Demand with Non-potable Water
Components of A Rainwater Harvesting System
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Meet Demand with Non-potable Water
Water Balance and System Sizing
The supply (amount that can be collected and
stored) must equal or exceed the demand
(anticipated amount that will be used)
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Meet Demand with Non-potable Water
System Sizing Example
Assumptions demand of 3,000 gal/mo collection
efficiency of 85 .62 gal/S.F. of catchment per
inch of rain 10,000 gallon storage capacity
1,000 gallon starting volume Dallas, Texas
location
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Deliver Water Efficiently
Avoid waste through overspray and evaporation.
Deliver directly to the plant.
Drip Irrigation
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Deliver Water Efficiently
Apply water only when and where it is needed.
Rain Sensor
Irrigation Zones
WeatherTrak Controller
Soil Moisture Sensor
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The Lady Bird Johnson Wildflower Research Center
Austin, Texas

• 70,000 gallons of total cistern storage
  capacity
• 17,000 S.F. of catchment area
• Broken up into several catchments and cisterns
  throughout the site
• Aesthetic / experiential system created by
  conveying water through aqueducts to exposed
  above-ground cisterns
• Local materials create a sense of place
• Used solely for irrigation

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The Lady Bird Johnson Wildflower Research Center
Austin, Texas
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The Southface Energy Institute Atlanta, Georgia

• 1,750 gallon rooftop cistern for toilet
  flushing and mechanical demands
• Below-grade cistern stores site runoff for
  non-potable uses (irrigation)
• Collector area should yield approximately
  42,000 gallons per average year
• Combined with efficient interior fixtures,
  this results in a total water savings of
  150,000 gallons per year when compared to a
  comparable conventional building a 74
  reduction.

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Final Thoughts

• Potable water should not be used for landscape
  irrigation.
• However, allowance should be made for plant
  establishment (first 1-3 years).
• Although the landscape industry has taken some
  short-term hits due to the drought, there are
  tremendous long-term business opportunities
• Rainwater catchment design and installation
• Low-impact stormwater design and installation
• Xeriscape design and installation
• Research / Propogation of new landscape plants
• Landscape management
• Efficient irrigation design and recycling
• Soil restoration

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Resources http//www.twdb.state.tx.us/assistance/
conservation/alternative_technologies/rainwater_ha
rvesting/rain.asp