SOUTHMOST REGIONAL WATER AUTHORITY

Texas Alliance of Groundwater Districts

October 29, 2014

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OUTLINE• About BPUB

• BPUB Surface Water Supply and Treatment

• SRWA Brackish Groundwater Desalination

• SRWA Microfiltration Project

• Benefits and Challenges

• Seawater Desalination

• Long-Term Water Supply Strategy

• Water-Energy Nexus

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ABOUT BPUB• Municipally-owned utility• Commission appointed 7 Member Board with the Mayor serving as an Ex-

Officio voting Member• Full-service utility:

• Electric, Water, Wastewater & Natural Gas• 540 Employees• Approximately 50,000 customers• $190 million total revenue

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PRIMARY WATER SOURCE• Rio Grande

The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico–United States border.

• Falcon/Amistad Lakes

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Water Supply Management

• TCEQ Watermaster Program

• Municipal Water Rights• 31,133.631 acre-feet• 7 day advance order for travel time

• Permit 1838 (Surplus water)• 40,000 acre-feet• Intermittently available, depending on river flows• Maintain resaca levels

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Brownsville ResacasResaca Del Rancho Viejo

Resaca De La Guerra

Town Resaca

Rio Grande

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Rio Grande at Brownsville Low Flows

Spring 2001 Summer 2002

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Rio Grande at Brownsville High Flows

October 10, 2008 July 26, 2010

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Off-Channel Reservoirs

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Water Reservoirs• Short-term storage

• Total storage capacity

• 187 MG (8 days)

• Reservoir 1 - 48 MG

• Reservoir 2 - 139 MG

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Surface Water Treatment• 2 Conventional treatment plants (20 MGD each)• Provide 76% of potable water to Brownsville

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Southmost Regional Water Authority Partners

Town of Indian Lake 0.20%

Brownsville Navigation District 2.10%

City of Los Fresnos 2.28%

Valley Municipal Utility District No.2 2.51%

Brownsville Public Utilities Board 92.91%

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SRWA Background• SRWA: Conservation and Reclamation

District formed in 1981 to address long-term regional water supply issues for southern Cameron County

• Dormant until 2000, then resurrected in response to the extended drought of the late 1990’s

• Partners came together to consider using brackish groundwater as an alternate water supply

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1996BPUB & TWDB: Study on brackish groundwater

2001Regional brackish water feasibility study & well field evaluation

2002Engineering design

2004Brackish Groundwater Treatment Facility construction completed

2015 Microfiltration pretreatment and expansion project complete

Time Line

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SRWA Brackish Groundwater Treatment Facility

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Brackish Groundwater DesalinationRO Membrane Treatment Facility

• Construction completed in 2004

• 7.5 MGD Design Capacity

• 20 Brackish groundwater wells

• Groundwater: 3,000 mg/L total dissolved solids (TDS)

• Concentrate waste stream 13,000 mg/L TDS drain ditch

• TCEQ Discharge Permit: TDS Daily Max—35,339 mg/L

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Reverse Osmosis Membrane Process

RO Membrane Process--Video

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SRWA Brackish Groundwater Wells• 20 Brackish groundwater wells

• Well depth: approximately 250-300 feet

• Well pump rate: 330 – 400 gpm

• Groundwater: 3,000 mg/L total dissolved solids (TDS)

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• Original Construction Costs:

$29 Million

• Funding Source: Revenue Bonds

• 8,400 acre-feet of water rights savings (equivalent to $17 Million)

• FY 2014 O&M Budget: $3 Million• Electrical: 23% of operational costs• Chemicals: 40% of operational costs

• FY2013 Unit Costs:

• $1.42 per kgals (O&M)• $2.46 per kgals (Debt Service and

O&M)

SRWA Cost Summary

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SRWA Microfiltration ProjectPretreatment for RO process• USEPA reduced arsenic level in drinking

water standards in 2006• Install 12 MGD Pall microfiltration system

for arsenic and iron removal• Expands plant capacity to 11 MGD• Cost - $13 million

• $9,295,000 No-interest TWDB Loan• $3,795,000 Low-interest (below

market) TWDB Loan

• Estimated construction costs: $11,413,578.15• Construction Start Date – May 2013• Completion Date – January 2015

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Degasifier

Cartridge Filters

RO Membrane

Array

Blending By-Pass

To Distribution System

Treated Water Storage

Post-treatment Chemicals

Concentrate Disposal

Chemical Pre-treatment

BRACKISH WATER TREATMENTCONCENTRATE MANAGEMENT AND

DISPOSAL

DELIVERY OF POTABLE WATER

Energy Recovery Turbine

Well Field

Collection and Conveyance System

GROUNDWATER DEVELOPMENT

Micro Filtration

Treatment Process

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SRWA Benefits and ChallengesBenefits• Alternate water supply• Independent of Rio Grande• Water rights savings• Produces high quality water• Modular design

Challenges• Arsenic levels in groundwater • Higher operating costs• Discharge permit• Specialized training (SCMA)

• 81st Texas Legislature (2009) provided funding to implement the TWDB Brackish Resources Aquifer Characterization System (BRACS) program

• 83rd Texas Legislature (2013) provided additional funding for personnel

Brackish groundwater in the major and minor aquifers Source: modified from LBG-Guyton, 2003

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2.7 billion acre-feet of brackish groundwater estimated in Texas

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Brackish Groundwater in the Gulf Coast

Aquifer, Lower Rio Grande Valley, Texas

TWDB Report 383 September 2014

Slightly Saline 40 million acre-feetModerately Saline 112 million acre-feet

Very Saline 123 million acre-feet

Brackish Groundwater Volume

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Brownsville Public Water Supply

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Brownsville Public Water Supply

54%

46%

Projected Proportions after SRWA Expansion

Surface Water PlantsSRWA

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Seawater Desalination

Pilot Study: $3,177,408 (Actual)• TWDB Funding $1,340,000

25 MGD Full-scale facility: $182.4 Million• (Pilot Study Report, 2008)

2.5 MGD Demonstration: $22.5 Million• (Project Update, 2011)

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Long-Term Water Supply StrategyDiversification• Surface Water

• Purchase water rights• Increase storage capacity in resacas

• Brackish Groundwater Desalination• Southmost Regional Water Authority RO

Treatment Facility• Seawater Desalination

• Pilot plant – Port of Brownsville• Texas desal project – proactively identify

environmental concerns• Phase 1: 2.5 MGD SWRO Plant

• Water Reuse – 8 MGD for Tenaska Project

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THANK YOU