The presentation discussed the San Antonio Water System's (SAWS) Twin Oaks Brackish Groundwater Desalination Program. The program will develop brackish groundwater from the Carrizo-Wilcox and Gulf Coast aquifers using reverse osmosis treatment and deep well injection of concentrate. Phase I will provide 12 million gallons per day by 2016 at an estimated cost of $192.66 million. The program aims to ultimately supply 30 million gallons per day through phased expansions to help meet the region's increasing water demands through 2060 in a cost-effective and sustainable manner.

1. TWCA 2014 Mid-Year Conference
W. John Seifert, Jr., P.E.
LBG-Guyton Associates
Kevin Morrison, P.G.
San Antonio Water System
Development of Brackish Groundwater Desalination
Project: SAWS Twin Oaks Brackish Groundwater
Desalination Program
June 12, 2014

2. June 12, 2014
SAWS Brackish Groundwater Desalination Program
Page 2
Topics
• Groundwater Hydrology
• Groundwater Supply Development
• Program Update

3. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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What is Brackish Groundwater?
• Practical Definition: Brackish groundwater
contains from 1,000 to 10,000 mg/L TDS
Fresh Brackish Saline
Fresh Slightly-saline Moderately-saline Very-saline
1,000 mg/L 3,000 mg/L 10,000 mg/L

4. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Why Consider Brackish Groundwater?
• By 2060
– Population will increase by 82% to 46.3 million
– Demand will increase by 22%
– Municipal demand will increase 71%
– Supply (existing sources) decrease 10%
– Advances in treatment technology
– Data from TWDB 2012 State Water Plan

5. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Carrizo-Wilcox
Gulf Coast
Hueco-Mesilla Bolsons
Major Aquifers

6. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Carrizo-Wilcox Aquifer

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SAWS Brackish Groundwater Desalination Program
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Gulf Coast Aquifer
(Wells >500 ft deep)

8. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Aquifers with Substantial Amounts of
Brackish Groundwater
• Carrizo-Wilcox
Interbedded sand, silt and clay
• Gulf Coast
Interbedded sand, silt and clay
• Hueco-Messilla Bolsons
Silt, sand and gravel

9. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Favorable Conditions for a Brackish
Groundwater Project
• Water quantity adequate
• Water quality acceptable
– Total dissolved solids content slightly saline to
moderately saline
• Resource located in reasonable proximity to demand
• Regulatory environment reasonable
• RO Concentrate Management can be cost contained
• Project effects are acceptable

10. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Carrizo-Wilcox Aquifer
- Strive for locations with
greater areal extent of resource

11. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Geologic Description of an Area
•Electric Log
Data Point

12. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Carrizo-Wilcox and Gulf Coast Aquifers
Brackish Groundwater Resource Below Fresh Groundwater
Land Surface
Increasing
Depth
Brackish Water Sand
(Yellow)
Freshwater Sand
(Blue)
Clay
(Brown)

13. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Wilcox Brackish Sands in Gonzales County
F. Passmore #1

14. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Groundwater
Supply
Development

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SAWS Brackish Groundwater Desalination Program
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Sequence of Supply Development
• Evaluate desk top data
• Outline area for test drilling if needed
• Perform drilling and water quality testing
• Design wells and wellfield with appropriate well
spacing
• Construct and test wells and evaluate water quality
data
• Equip wells and construct water conveyance
infrastructure

16. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Screen Installation And Gravel Packing

17. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Large Capacity Brackish Water Production Well

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SAWS Brackish Groundwater Desalination Program
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Production Well Testing
Obtain data on aquifer
productivity,
can be used for
groundwater flow modeling
Obtain water quality data
Collect data regarding
well efficiency

19. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Program Update

20. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Program General Information
• Source Water
– Lower Wilcox Formation
– 12 Production Wells – Avg. depth 1,600 ft.
• Treatment Process
– Reverse Osmosis – 90% Recovery
• Concentrate Disposal
– Deep Well Injection – 5,000 ft. depth
– Two injection wells required for Phase I

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SAWS Brackish Groundwater Desalination Program
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Program Components
• Production Wells
• Conveyance System (Pipelines)
• Reverse Osmosis Treatment Plant
• Injection Wells
• Electrical / SCADA

22. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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SAWS BGD Program
• Phase I (2016)
– 12 MGD or 13,440
Acre-feet/yr.
• Phase II (2021)
– 12 MGD or 13,440
Acre-feet/yr.
• Phase III (2026)
– 6 MGD or 6,720
Acre-feet/yr.
• Total
– 30 MGD or 33,600
Acre-feet/yr.

23. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Lessons Learned from Past Projects
• Program Manager not having control over designers
• Low bid contractor may not be best qualified
• No contractor’s input in the design document
preparation
• Claims, litigation and delays
• Change orders
• Lack of cooperation

24. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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• Designer Engineers are under the contract of the
Program Manager
• Sub-contractors are selected based on qualifications
and experience under the Construction Manager At
Risk (CMAR) procurement
• CMAR contractor were involved in the design phase
• Performance Incentive proposed
Procurement Plan

25. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Program Structure
- 4 Design Teams
- 20 Design Sub-Consultants
- 17 SMWB Firms
- 21 Local Firms
SAWS
Construction Manager at Risk
(CMAR) Zachry Parsons Water
Resources JV
Program Manager
Black & Veatch Corp.
Sub-ContractorsDesign Sub-Consultants
- 12 Construction Packages
- Multiple Subcontractors

26. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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20132012
Conceptual
Design
Pre-
Construction
Design
2015 20162014
Program
Completion October
2016
Construction Management Services
Construction
Commi-
ssion
Commi-
ssion
Warranty
Warranty
2017 2018
Program
Manager
(PM)
Construction
Manager at Risk
(CMAR)
GMP Board Award
March 2014
CMAR Process
• Process allows:
– Contractor’s input in the design
– Engineer’s involvement in construction planning
– Qualification based selection
– Guaranteed maximum price (GMP)
– Pursue SAWS SMWB goals

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SAWS Brackish Groundwater Desalination Program
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Guaranteed Maximum Price
• CMAR will publicly bid each construction
package and recommend most qualified best
value sub-contractor
• The payment to CMAR will be based on actual
cost of construction not to exceed the GMP
• Should the actual cost be lower than the GMP,
the difference will be a credit to SAWS

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SAWS Brackish Groundwater Desalination Program
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Shared Performance Incentives
• Maximum of $250,000 to Program Manager
• Maximum of $750,000 to CMAR
• Objective Parameters:
• Budget
• Completion Schedule
• Change Control
• Subjective Parameters:
• Partnering, Quality of service, Conflict Resolution,
Timely Responses

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SAWS Brackish Groundwater Desalination Program
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RO Treatment
Acid
CF
AS
Calcite Contactor,
Degasification,
Sodium hydroxide
Product
Well
Concentrate
Disposal
Raw Water Blending
RO
Concentrate
Pre-treatment
Primary treatment
Post treatment
AS: Anti-scalent
CF: Cartridge Filter
13.11MGD
2MGD
10 MGD
1.11MGD
11.11MGD
12 MGD

30. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Production vs. Disposal
Land Surface
Georgetown
Edwards &
Upper Glen Rose
Limestone
TD = 5,040 ft.
Midway Shale
Anacacho
Limestone
Navarro Clay
Not to Scale
TD = 1,600 ft.
Production Well Injection Well
Confining
Zone
~2,360 ft.
Thick
Wilcox Sand
(Brackish Water)
Upper Wilcox Clay
Eagle Ford
Shale,
Buda Limestone,
& Del Rio Clay
Austin Chalk
Carrizo Sand
(Fresh Water)
Injection
Zone
~ 860 ft.
Thick
Production
Zone
~ 600 ft. Thick

31. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Remaining Work for Phase I
• Additional four
production wells
• Additional injection
well
• Reverse Osmosis
treatment plant
• Pipelines
• SCADA and Electrical
system

32. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Construction Package Procurement
Work
Package
Description
SAWS Approval of
CMAR
Recommendation
1 Enabling (Silt Fencing / Site Fencing) May-14
2 Site Work May-14
3 Foundation May-14
4 Electrical / SCADA May-14
5 Water Treatment Plant Jun-14
6 Pipelines Jun-14
7 Access Roads Jun-14
8 Well Fit Out Jul-14
9 Production Wells Jul-14
10 Injection Wells Jul-14
11 Landscaping Dec-14
12 Security

33. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Cost
• Phase I total
estimated
construction cost is
$192.66 million
• $/AF: $1,177 / AF
Phase I

34. June 12, 2014
SAWS Brackish Groundwater Desalination Program
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Questions?

35. TWCA 2014 Mid-Year Conference
W. John Seifert, Jr., P.E.
LBG-Guyton Associates
Kevin Morrison, P.G.
San Antonio Water System
Development of Brackish Groundwater Desalination
Project: SAWS Twin Oaks Brackish Groundwater
Desalination Program
June 12, 2014