Robert Macias, San Antonio Water System James Dwyer, P.E., CH2M HILL

Transcription

1 Robert Macias, San Antonio Water System James Dwyer, P.E., CH2M HILL

2 Agenda Edwards Aquifer A sole-source aquifer for the San Antonio Water System (SAWS) EAA permit and implications for SAWS Aquifer storage and recovery as a drought management strategy System details Historical performance Future Operation Under EARIP Summary

3 San Antonio, Texas

4 The Edwards Aquifer; A Unique Ecological System

5 The Edwards Aquifer; A Unique Ecological System Dr. Glenn Longley

6 The Edwards Aquifer; A Unique Ecological System Dr. Glenn Longley Dr. Glenn Longley

7 The Edwards Aquifer; A Unique Ecological System Dr. Glenn Longley Dr. Glenn Longley Dr. Glenn Longley

8 The Edwards Aquifer; A Unique Ecological System Dr. Glenn Longley Dr. Glenn Longley Dr. Glenn Longley Gregg Eckhardt

9 Sole-source aquifer Springs historically dependable source First recorded use by Spanish missions 1891 First municipal supply well Edwards Underground Water District created primarily to study and monitor, no regulatory authority EPA designated Edwards as the first "sole source aquifer"; more than 50% of supply, no readily available alternative

10

11 Edwards Aquifer Authority Permit Critical period triggers based on 10-day average J17 level and/or flow in Comal or San Marcos Springs Stage I 20% cut Stage II- 30% cut Stage III 35% cut Stage IV- 40% cut

12 Historical Perspective 660 MSL 630 MSL

13 Historical Perspective Daily High (Elev) J J-89 M-89 M-89 J-89 S-89 N-89 J-90 M-90 M-90 J-90 S-90 N-90 J-91 M-91 M-91 J-91 S-91 N-91 J % Reduction

14 Historical Perspective Daily High (Elev) J J-89 M-89 M-89 J-89 S-89 N-89 J-90 M-90 M-90 J-90 S-90 N-90 J-91 M-91 M-91 J-91 S-91 N-91 J % Reduction % Reduction

15

16 What is ASR? Environmentally friendly method of storing drinking water Edwards Aquifer water is transported from SAWS distribution system and stored in the Carrizo Aquifer Water stored during wet or low use periods (winter), recovered during times of drought ASR used to help maximize future allocations of Edwards Aquifer water

17 Edwards Optimization Monthly Demand ASR Storage ASR Recovery Annual Average Demand ASR Storage J F M A M J J A S O N Months D

18 ASR Injection Mode How ASR Works

19 ASR Recovery Mode How ASR Works

20 SAWS ASR Program Overview 30 Million Gallons per Day (MGD) Treatment Capacity 70 MGD High Service Pumping Capacity 60 MGD ASR Wellfield Storage Capacity 64 MGD Pipeline Capacity Integrates into the SAWS System at Artesia, Seale, and Randolph Pump Stations

21 Operations 120,000 ASR Storage History ( ) Cumulative Storage (ac-ft) 100,000 80,000 60,000 40,000 20,

22

23 Merging EARIP and SAWS ASR EARIP deliberations realized that the SAWS ASR may be useful as one component in a group of program components referred to as Bottom Up activities SAWS ASR holds the potential to address endangered species requirements and prevent the need for a new water resource project Merging the EARIP and SAWS use of the ASR reduces the total cost overall EARIP plan

24 ASR with EARIP SAWS manages the ASR whenever the J-17 well exceeds 630 feet msl SAWS may need to recharge between 630 and 660 feet msl When the J-17 well drops below 630 feet msl, and the region is in the Drought of Record (DOR), the ASR becomes dedicated to EARIP s habitat protection plan Production mode only Modeling shows that ASR will need to provide approximately 126,000 acre-feet of water, over eight years to meet a future DOR

25

26 EARIP & SAWS ASR Simulated operations contribute to a ~30 cfs benefit

27 Protecting Comal Spring Flows Simulated 593,000 AF pumping + no management strategies in place = 39 months of zero spring flow cfs Jan-52 Jan-53 Jan-54 Jan-55 Jan-56 Jan-57 Baseline

28 Phase I Components and ASR cfs Jan-52 Jan-53 Jan-54 Jan-55 Jan-56 Jan-57 Baseline Other Strategies ASR Phase I

29

30 SAWS ASR Flexible operations have been displayed with the early implementation of ASR technology by SAWS Project has exceeded all expectations Stored water quality looks as expected Valuable storage for San Antonio EARIP strategy

31 Moving forward with ASR Regional EARIP commitment Maintain bank in long-term storage SAWS Water Management Plan (WMP) Explore effective summer peak management strategies Plan for future studies to more effectively understand hydrogeology of site Phase II EARIP Possibly further protect springflow, if necessary

32