Impacts of Salinity on El Paso’s Surface Water Supply

presented at the Annual Salinity Management and Desalination

Summit

December 8, 2003

Michael P. Fahy Planning and Development Manager

Colorado

New Mexico

Texas

United States

Mexico

Taos

Santa Fe

Albuquerque

Socorro

Las Cruces

El PasoJuarez

Ft. Quitman

Rio

Gran

deTexas

Colorado

New Mexico

Rio Grande Project

• Bureau of Reclamation Project (1916)

• Extends from Elephant Butte Lake in New Mexico to Fort Quitman in Texas

• 90,500 irrigated acres in New Mexico

• Originally 69,010 irrigated areas in Texas

• During full allocation years, Bureau delivers 931,841 AF at canal headings with Reservoir release of 790,000 AF

Rio Grande Project (con’t)

• Encroachment by urbanization in both states

• Complex systems of diversion dams, canals, laterals and agricultural drains

• Agricultural and municipal releases are made from March through September during full allotment years, shorter period during droughts

Elephant Butte Reservoir

Average Elev.

Spillway Elev.

History of Agricultural Drains

• Project was originally constructed without drains

• Drains were constructed in the 1930’s to improve drainage, mitigate saturated soil conditions, and generally improve crop production

• Excavated between fields, 8 to 12 feet deep, variable width depending on flow capacity

• All drains eventually discharge back into the river

Del Rio Drain

East Drain

Picacho Drain

La Mesa Drain

Montoya Drain

Rio Grande Project

Major Drains in Mesilla Valley

River Points of Entry

New Mexico

Texas

Rio G

rande

Anthony

Franklin Mts.

McC

ombs

Canutillo

NEW MEXICO

TEXAS

Vinton

Railr

oad

Dr.

Dyer

St.

Transmountain

Doniphan

USA

MEXICO

Ciudad Juarez

Montana

Yar

brou

gh

Zara

gosa

Airport

America

s A

ve.

Alameda

Fort Bliss

Military Reservation

Sunlan

d Par

k

Mesa Dr.

Rio G

rande

N

Water System

Robertson/Umbenhauer Water Treatment Plant

Nor

th-S

outh

Fre

eway

Jonathan Rogers Water Treatment Plant

Elephant Butte

Source - Rio Grande Conveyance System

Water Management and Source Water Protection Study Part 1

Data Evaluation Report

Boyle Engineering Corporation / Parsons Engineering Croporation, Inc. March 1997

0

200

400

600

800

1000

1200

1400

TDS

(mg/

L)

Irrigation Non-Irrigation Yearly

Average of Intermittent TDS, Period - 1981 to 1984Irrigation Season, Non-Irrigation Season, Yearly

Rio Grande Below Caballo Reservoir

Rio Grande Below Leasburg Dam

Rio Grande Below Mesilla Dam

Rio Grande at El Paso

0200400600800

10001200140016001800

TDS

(mg/

L)

Irrigation Season Non-irrigation Season

Rio Grande Project Major Drains Average of Intermittent TDS, Period - 1981 to 1984

Del Rio DrainLa Mesa DrainEast DrainMontoya Drain

Note: Average Individual Annual Drain Flows Range from 25 to 65 cfs

Rio Grande Average Monthly TDS Concentrations at American Diversion Dam Under Current Conditions

0

200

400

600

800

1000

1200

1400

1600

Jan96.7%

Feb80%

Mar6.7%

Apr3.3%

May10%

Jun6.7%

Jul6.7%

Aug13.3 %

Sep40%

Oct90%

Nov96.7%

Dec96.7%

Month % Exceedance

TDS

(mg/

L)

1461

1313

744784

836786 819 844

1005

1302

1459 1461

TDS Limit

Ref: Boyle-Parsons Drain Mitigation Report to the NM-TX Water Commission (1998)

0

50

100

150

200

250

300

350

400

450

500

Jan96.7%

Feb86.7%

Mar10%

Apr10%

May20%

Jun6.7%

Jul16.7%

Aug23.3 %

Sep66.7%

Oct93.3%

Nov96.7%

Dec96.7%

Sulfate Limit

Rio Grande Average Monthly Sulfate Concentrations at American Diversion Dam Under Current Conditions

Month % Exceedance

Sulfa

te (m

g/L)

478

430

245260

277260 271 279

331

427

478 478

Ref: Boyle-Parsons Drain Mitigation Report to the NM-TX Water Commission (1998)

El Paso’s Current Methods for Planning and Operation of Two Water Treatment Plants

• Routine monitoring of water quality at canal diversions

• Plants are shut down when sulfates near 300 ppm or TDS approaches 1000 ppm

• Routine flow monitoring at upstream gauging stations

• Regular communications with irrigation districts and Bureau of Reclamation regarding release orders and water quality

El Paso’s Current Methods for Planning and Operation of Two Water Treatment Plants (con’t)

• Conductivity meters have been installed in the Rio Grande and within four drains at the state line

• Intent is to provide continuous, “real-time” water quality monitoring with approx. 1-day lead time to El Paso

• EPWU provides financial support for the newly formed Paso del Norte Watershed Council with established goal of improving river water quality

El Paso’s Current Methods for Planning and Operation of Two Water Treatment Plants (con’t)

East Drain

West Drain

Rio Grande @ Anthony Bridge

Newmexas DrainAnthony Drain

EPWU/EBIDConductivity Probes

Potential Longer-Term Techniques for Managing Salinity

Studies conducted as part of the Regional Sustainable Water Projects of the NM-TX Water Commission:

• Retire agricultural land/manage saline lands

• Treat drain flows

• Dilute drain flows with ground water

Potential Longer-Term Techniques for Managing Salinity (con’t)

• Impound and release drain flows

• Relocate point of discharge for critical drains

• Relocate water plant diversion locations

• Costs for some of these alternatives range from $1.0 million to more than $15.0 million

• Most require approval by agencies with jurisdictional authority

Questions ?