saws' twin oaks aquifer storage and recovery project saws' twin oaks aquifer storage and...

SAWS' Twin OaksAquifer Storage andRecovery Project


October 11 2010October 11 2010October 11 2010October 11 2010

Texas Innovative Water 2010

Roberto MaciasPlant Manager

SAWS' Twin Oaks Aquifer Storage and Recovery Project UpdateSAWS' Twin Oaks Aquifer Storage and Recovery Project Update

Project History• Part of SAWS' 50-Year Water Supply Plan,

adopted in 1998• 3,200 acres purchased in south Bexar, Atascosa,

and Wilson counties in 2000 and 2001

• Original project concept was for Carrizo production only

• 2002 agreement with Evergreen Underground Water District limited Carrizo production to 6,400 af/year

ASRsite


PropertiesIncludedin WaterResource andManagementAgreement


Project History• Facility online in 2004• Phase I included 17 wells

and 30 mgd water treatment facility

• Phase II (completed 2009) included 12 additional wells to increase storage/recovery capacity to 64 mgd

• Phase IIA included local Carrizo wells– 7 wells for exclusive Carrizo production

• ≈ $250,000,000 invested so far

Twin Oaks treatment facilityTwin Oaks treatment facility


Changing Operational Plan

• Carrizo only

• Seasonal benefit

• Long-term storage

• Both seasonal benefit and long-term storage


Welllocations

ASR wellASR well

monitoring wellmonitoring well

Carrizo wellCarrizo well

pilot desal wellpilot desal well


Current WorkDesalination Pilot Plant


0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

Jan

-04

Jul-

04

Jan

-05

Jul-

05

Jan

-06

Jul-

06

Jan

-07

Jul-

07

Jan

-08

Jul-

08

Jan

-09

Jul-

09

Jan

-10

Jul-

10

Current storage volume = 81,556 af

acre-feet

cumulative volumein storage

Water in Storage at Twin Oaks2004 to July 20, 2010


50,000

75,000

100,000

125,000

150,000

175,000

200,000

225,000

250,000

275,000

300,000

2009 2010 2011 2012 2013 2014 2015 2016 2017

Acre-Feet

Edwards Supply Owned (DS) Edwards Supply Leased (DS) Trinity ProjectLocal Carrizo Western Canyon ASR ProjectPermitted Supply Gaps

Existing Permitted SuppliesDrought of Record Impact Today (circa 2009)

High (126 GPCD)

Normal (116 GPCD)

Low (106 GPCD)

Permitted Supply Gaps

10,436 37,622 23,851


ASR and Permitted Supply Gap

0

100,000

200,000

300,000

400,000

2011 2012 2013 2014 2015 2016 2017 2018 2019

acre-feet

Total Supplies

ASR Storagedemand at

116 gpcd


USGS activities

• Completed Scientific Investigations Report Quality of Groundwater at and near an Aquifer Storage and Recovery Site, Bexar, Atascosa, and Wilson Counties, Texas, June 2004 - August 2008– "no trends that might have been caused by migration of

injected Edwards aquifer water were observed"• Continued sampling of 15 off-site wells for water quality • 1 ASR monitor well equipped with a water quality monitor• 3-D model pilot study in progress (in next year’s Joint Funding

Agreement). • Will assist in selection of possible new monitoring well site(s)


Storage volume by ASR well

MillionGallonsInjected


Migration of stored water

From CH2MHill Technical Memorandum, South Bexar County ASR Recovery Assessment, Jan. 7, 2004


Mitigation program

• 240 wells investigated• 101 wells where mitigation has been completed:

– 33 wells had pumps lowered– 59 new wells drilled– 9 wells with no mitigation required


ASR highlights

• Project has exceeded all expectations

• Water quality does not degrade

• Amount of water available for storage and withdrawal has significant impacts on overall water supply plan


Moving forward with ASR

• Maintain bank in long-term storage• Explore effective summer peak management

strategies• Plan for future studies to understand

hydrodynamics of site



October 11 2010October 11 2010October 11 2010October 11 2010

Texas Innovative Water 2010

Roberto MaciasPlant Manager

saws' twin oaks aquifer storage and recovery project saws' twin oaks aquifer storage and...

Documents

saws twin oaks aquifer

recovery project updateasr

recovery site

twin oaks2004

original project concept

offsite wells

additional wells

texas innovative water