Water Use & Demand Management

Transcription

1 Review: Natural Water Budget Water Use & Demand Management Precipitation = Evapotranspiration + Runoff + Recharge + Change in Storage Ppt = ET + RO + Rchg + S 1 2 Review: Anthro. Water Balance How do we quantify these terms? Water supplies or sources Rivers & Dams Surface Water Aquifers Ground Water Treated Effluent Reclaimed Imported water CAP Water demands or uses Irrigation Water Agricultural Homes & Cities Municipal or Public Supply Industrial also Commercial Other Consider Municipal use: Muni + dm = f( )? Inside = f( )? SW + GW + Eff + Imports = Ag + Muni + Ind + other 3 4 How do we quantify these terms? Consider Municipal use: Muni + dm = f(use, Pop, Growth, GPCD, inside, outside, ) Inside = f(family size, appliances, age, habits, ) Why Demand Management? What if you can t find more water? Lower demand so as not to exceed supply Cheaper than increasing supply May allow more growth But: It may be difficult to quantify water savings through demand management Conserving too much may reduce flexibility in times of drought 5 6

2 Strategies Minimize Unaccounted-for Water Shift Uses Ag to Urban Highly Consumptive to low water use Conservation Ag Industrial Indoor Outdoor Reduce demand Minimize Unaccounted-for Water Replace or repair leaky water mains Minimize system losses Replace worn water meters But Both fairly expensive 7 8 Shift Uses Ag to Urban Household Water Use Ag use: 4-5 af/ac Urban use: City blk ~ 4.5 ac, 16 homes, 1 af/hh (high) => 3.5 af/ac Which is larger Indoor or Outdoor use? Out 58% In 42% 121 gpcd Rank common indoor water uses from highest to lowest total volume? Pick Rank: from: Faucets Toilet Shower/tub Washing machine Shower/tub Toliet Faucets Washing machine 9 10 Age of construction matters Household Water Use 60 gpcd 40 gpcd faucet 19% toilet 34% faucet toilet shower 22% washer shower washer 11 12

3 Typical SW Values What does it mean to Beat the Peak? City GPCD Albuquerque, NM 95 El Paso, TX 114 Tucson 120 Mesa 123 Glendale 131 $35/mo Tempe 140 Phoenix 165 Scottsdale 169 Fresno, CA 261 $108/mo Pete the Beak New TW Water Smart Water Smart Water Audits Do your part, be water smart everyday Conservation Incentive Programs Toilet rebates 12,000 new x 3 gal x 365 days x 11 f/d = 144 Mgal/yr saved (443 af/y) Washer rebates Rainwater harvesting ~$2,000 Gray water cms3.tucsonaz.gov/water/watersmart Partnerships Water Smart Rainwater harvesting incentives cms3.tucsonaz.gov/wa ter/rwh-l2steps Residential Drip Irrig. Gray water rebate Hands-on Waterwise garden design Water Audits credit: Tucson Water content SmartScape Residential Conservation: Cost/Benefit Soils, Plants & Water Desert - Adapted Plants Automated Irrigation Systems Landscape Water Management Landscape Design & Renovation Plant Selection & Installation credit: Tucson Water Plant Disorders & Weeds Maintaining Desert - Adapted Plants Integrated Pest Management 17 SWH 8(6), 2009

4 Pricing Seasonal considerations Increase water charges to increase conservation Block rate structure: higher water users may more for their water (see next slide) May reflect the scarcity value of water Is it ethical? What about the right to water? $50 $40 $ Bill inserts Flyers Billboards Conservation Education Public service announcements Workshops and Events Can make water users aware of the need to conserve water Cheap! But Very difficult to prove its effectiveness Indoor and Outdoor Use Efficient appliances dishwashers, frontloading washing machines Fixture retrofits low-flow toilets, showerheads, and faucets Landscape conservation measures xeriscaping, turf removal, water harvesting, drip irrigation Rebates may be offered for any of the above Las Vegas pays people $1/sq ft. to remove turf. Offsetting behavior? Efficiency? Indoor use Outdoor use Pools (~500 ft 2 ) loose 50 gal/ft 2 /yr Evaporative coolers (2000 hrs) w/ bleed ~10 gal/hr w/o bleed ~ 3 gal/hr Garden hose (~15 min) 10 gal/min Drip Irrigation (30 min, 150 d) 10 gal/hr Car Wash (~5 min, weekly) 5 gal/min Mist system (5 hrs/d, 100 d) 4 gal/hr 23 Cheaper than air but System w/ bleed 10 gal/hr System w/o bleed 3 gal/hr Typical usage 2000 hrs (83 days) So 20,000 gal/yr Evaporative Coolers 2012 The University of Arizona HWR203 24

5 Appliance and Fixture Use Water meter traces reveal details of domestic demand Problems found with aging ULF toilets Percent of Households Experiencing Problem Double Flush Flapper Leak High Flush Volume Some Problem Bathroom 2012 The University of Arizona HWR203 Reclaimed Water Link between supply and demand management What is it? Why use it? Who uses it? How is it treated? Gray Water Gray water involves rerouting the outflow pipes from tubs and showers, washing machines, dishwashers, evaporative coolers, and some sinks. Used water irrigates outdoor landscaping Regulations are strict and must be followed closely. Gray Water GRAY WATER IS WATER FROM THE BATH, SHOWER, WASHING MACHINE OR BATHROOM THAT CAN BE USED FOR IRRIGATION NEEDS CISTERN INSTALLED FOR GRAYWATER REUSE SYSTEM * The Water Conservation Alliance of Southern Arizona (Water CASA) is conducting a study to determine health risk associated with low-tech methods of graywater use

6 7 Principles of Xeriscaping Good planning & design Low water use plants Appropriate turf areas Efficient irrigation Soil improvements Use of mulches Appropriate maintenance Credit: Kent Newland Credit: Charles Mann Photography 31