Alternative Water Supplies in Texas

Central Texas Water Conservation Symposium

Jorge A. Arroyo, PEWater Management Consultant

February 2014

ALTERNATIVE…. TO WHAT?

…WHEN IS AN ALTERNATIVE NO LONGER AN ALTERNATIVE?

NOT AN ALTERNATIVE TO WATER CONSERVATION

Alternative Water Supplies

• Rain collection systems• Water reuse• Managed aquifer recharge• Desalination

Rain Collection Systems

Source: Texas Water Development Board

Rain Collection Systems: Sole Source

• Volume of rain• Water use• Storage• Treatment• Operation and maintenance

Kight Residence RWH System- Boerne

Source: Texas Water Development Board

Rainwater Harvesting

Indoor demand Irrigation Total

demandAverage rainfall

Collection surface size

Gallons/ft2 collection coefficient

Efficiency factor

Rainfall collected

(85% efficiency)

End of month

storage (*)

January 3,000 0.0 3,000 2.12 2,500 0.62 0.85 2,792 0February 3,000 0.0 3,000 2.41 2,500 0.62 0.85 3,179 0March 3,000 150.0 3,150 2.23 2,500 0.62 0.85 2,941 0April 3,000 150.0 3,150 2.97 2,500 0.62 0.85 3,907 519May 3,000 150.0 3,150 4.02 2,500 0.62 0.85 5,294 2,664June 3,000 150.0 3,150 3.39 2,500 0.62 0.85 4,460 3,974July 3,000 150.0 3,150 1.96 2,500 0.62 0.85 2,578 3,402August 3,000 150.0 3,150 2.21 2,500 0.62 0.85 2,907 3,159September 3,000 150.0 3,150 3.17 2,500 0.62 0.85 4,175 4,184October 3,000 150.0 3,150 3.44 2,500 0.62 0.85 4,528 5,562November 3,000 0.0 3,000 2.68 2,500 0.62 0.85 3,536 6,099December 3,000 0.0 3,000 2.35 2,500 0.62 0.85 3,099 6,198

Change to fit your conditions

Catchment Area (sq. ft.) 2,500Monthly Indoor Demand (gals) 3,000Outdoor Demand (gals) 150Water in Storage to Begin (gal) 0Tank Size (gal) 10,000

(*) starting with water in storage

RWH System Sizing Calculator

http://www.twdb.texas.gov/innovativewater/rainwater/resources.asp

Rain Collection Systems – InstitutionalRedbud Center - Lower Colorado River Authority, Austin

Source: Texas Water Development Board

Rain Collection Systems: Subdivision

• Subdivision-Scale Rainwater Harvesting Systems as a Water Supply Strategy– The Meadows Center for Water and the

Environment: Texas State University, San Marcos– Feasibility, facility design and management

protocol, backup supply – Texas Hill Country.

Indirect Water Reuse

Direct Water Reuse

12

2012 State Water PlanRecommended Water Management Strategies

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

2010 2020 2030 2040 2050 2060

Acre

-feet

/yr

New Major Reservoirs Conservation Other Surface Water Reuse Desalination Conjunctive use ASR Other Groundwater

13

Reuse to be added in the next 17 years*

Region 2010 decade 2020 decade

C 1,937 229,825 E - 4,312 F - 12,380 G 18,723 21,610 H 168 33,813 I - 2,872 K 54,311 8,765 L 21,666 4,380 M 3,537 7,474 N 250 - O - 2,240

Total 100,592 327,671 * 2012 State Water Plan-DB12

Managed Aquifer Recharge

Aquifer Storage and Recovery

In operation• Kerrville• El Paso*• San Antonio

Potential• Eastern Kerr County• New Braunfels• Guadalupe Blanco River

Authority (Lulling)• Barton Springs Edwards

Aquifer District

• Legislation filed to facilitate ASR projects• 83rd Texas Legislature – HB 3013

Desalination of Ocean and Brackish Groundwater Sources

367 miles of coastline Availability of sites Proximity to demand

centers

Texas has an estimated 2.7 billion acre-feet of brackish groundwater

Saline Water Desalinated Water

Concentrate and power

Brackish Groundwater Desalination

18

• 120 million gallons per day

• 44 facilities [25,000 gpd or more]

• El Paso’s Kay Bailey Hutchison Brackish Groundwater Desalination: 27.5 MGD

Innovation in water supply

• Increase water supply efficiency• Sustainable use of sources• Cost of innovation– Research– Demonstration Jorge A. Arroyo

Water Management Consultant

jarroyo@austin.rr.com

512-497-0474