1. Brigit Afshar University of Texas at Austin Statistics in Water Resources May 2009

2. Conventional Rainwater Harvesting System Roof Catchment Storage Tank Gutter First-Flush Diverter 10 gal./1000 sq. ft. (TWDB) Downspout Overflow Spout Adapted from: Texas Commission on Environmental Quality (TCEQ). 2007. “Harvesting, Storing, and Treating Rainwater for Domestic Indoor Use.”

3. Feasibility  National Atmospheric Deposition Program (NADP) VS.

4. Domestic Indoor Water Demand Number of people per household3 Water Consumption of FixtureAssumptions Household Monthly (30-day) Demand Toilets Ultra Low Flow Toilets (post- 1993)1.6gal/flush6flushes/person/day864 Dual Flush1gal/flush liquids flushes/person/day0 1.6gal/flush solids flushes/person/day0 Baths and Showers Showerhead2.2gal/min5minutes/person/day990 Baths50gal/bath baths/day0 Faucets2.2gal/faucet/min5minutes/person/day990 Appliances (per-use, not per- person) Clothes washer (Front-loading, 18-25 gal)20gal/load2.6loads/week208 Dishwasher8gal/cycle0.7cycles/day168 TOTAL 3220 Source: TWDB; AWWA,1999

5. Assumptions Monthly Annual Indoor water demand (gallons)3220 Irrigation (gallons, Mar-Oct)150 Collection surface (sq. ft.)2500 Starting volume (gallons)3000 Collection rate (gal/in. rain/sq.ft)0.62 Collection efficiency0.85 Indoor water demand (gallons)38640 Irrigation (gallons, Mar-Oct)1200 Collection surface (sq. ft.)2500 Starting volume (gallons)10000 Collection rate (gal/in. rain/sq.ft)0.62 Collection efficiency0.85

6. Climate Regions of Texas Source: NADP, 2009Source: Texas Center for Policy Studies, 1995

8. Upper Rio Grande and Far West Month Irrigation Demand Total Demand (gallons) Average rainfall (inches) Rainfall collected (gallons) End-of-month storage (gal) January032200.584769.23549.2317 February032200.624822.24-1848.53 March15033700.539709.68-4508.84 April15033700.551726.38-7152.45 May15033701.1611529.5-8992.91 June15033701.8642455.6-9907.22 July15033702.4863274.8-10002.4 August15033702.7353602.7-9769.67 September15033702.0212662.5-10477.1 October15033701.5572051.9-11795.2 November032200.7751020.6-13994.5 December032200.684901.24-16313.3 Total:15.58020526

9. Northeast West Central

10. Annual Analysis

11. Texas Harvesting Potential RegionNeeds Met Water Saved (gallons/year) Far WestPartial 20118 High PlainsPartial 22456 Lower GulfYes 41008 North TexasYes 42283 NortheastYes 60482 South CentralYes 30177 Upper GulfYes 55119 West CentralYes 31381

12. United States Hydrologic Regions Source: NADP, 2009

15. United States Harvesting Potential RegionNeeds Met Water Saved (gallons/yr) 13 Rio GrandePartial27832 14 Upper COPartial23687 15 Lower COPartial14504 16 Great BasinPartial15955 AlaskaPartial22725

16. Questions?