Water Resources Issuesin the Lower Rio Grande

June 3, 2005

J. Phillip King, P.E.Assc. Professor/Assc. Dept. HeadDept. of Civil Engineering, NMSU

Consultant, EBID

Major LRG Water Issues

• Drought and Project Water Allocation – Reclamation, EBID, El Paso #1, Mexico

• Active Water Resource Management (AWRM) alternative administration regulations – OSE, Lower Rio Grande Water Users Organization (LRGWUO)

• Conversion of surface water to non – agricultural uses in LRG – EBID, Las Cruces, Doña Ana MDWCA, OSE

Caballo

ConveyanceSystem

IrrigatedLand

Groundwater

DrainFlows

Atm

osph

ere

SeepageExfiltration

Pum

ping

Return

Diversion

Bypass (spill)Delivery

Deep Percolation

StormFlow

Bypass (spill)

Seepage

Release

Rio G

rande

M&IUsers

PumpingDeep Perc.

Discharges

Imported WaterExported Water

Non-irrigatedLand

Rio Grande at El Paso

Pum

ping

Dee

p P

erco

lati

on

ETPrecip

ETPrecip

Drainage

ET Precip

Surface Water-Groundwater Interaction in the LRG

0.03%

0.49%

0.53%

0.76%

1.27%

6.81%

90.11%

Irrigated Agriculture

Public Water Systems

Commercial

Livestock

Domestic wells

Power

Industrial/Mining

Water Use by Sector in LRG

97 percent of LRG water use is irrigation or public water systems

The Rio Grande Project

• Water rights appropriated January 23, 1906• 90,640 water-righted acres in Elephant Butte Irrigation

District (EBID) in New Mexico• 69,010 water-righted acres in El Paso County Water

Improvement District No. 1 (EPCWID) in Texas• 60,000 acre-feet of water for the Republic of Mexico by

the Treaty of 1906• Construction largely completed by 1917; drainage

system built in 1920s• Operated as a single irrigation system by Bureau of

Reclamation• City of El Paso began treating surface water in 1940s• Districts paid off construction costs in late 1970s

Current Project Water Allocation

• BOR allocates water to US districts and Mexico– Based on water available for release storage

and actual river efficiency– Mexico gets their water first, and the

remainder is divided between EBID and EP#1 proportionately (57%/43%)

• Districts allot water to farmers based on BOR allocation and system conveyance efficiency

Drought Response

• Conjunctive management of surface water and groundwater– Robust river-connected aquifer used for

agriculture, M&I, domestic use– Short surface water supplies prompt

increased groundwater withdrawals– Groundwater withdrawals affect river

efficiency

Rio Grande Project Release and Diversion

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000

Caballo Release, AF

Pro

jec

t D

ive

rsio

n,

AF

51-78

79-02

03-04

1:1

Motivation for AWRM

• Manage surface water and groundwater intelligently to maximize beneficial use in New Mexico

• Maintain hydrologic health of the LRG• Protect senior water rights from impairment in

the absence of a completed adjudication• Protect downstream users in Texas and Mexico

from overuse in LRG• Provide mechanisms for out-of-priority users to

offset impacts on senior and downstream water users

Complications

• Rio Grande Operating Agreement• Project authority over surface water, OSE

authority over groundwater• Lack of clarity in relationship between surface

water and groundwater rights• Junior basic necessities

Current Status of AWRM

• State-wide regulations finalized• Metering order issued for all groundwater

diversions in LRG except single domestic wells• State is developing draft basin-specific

regulations for LRG to be released for review by LRGWUO in May - delayed 2 months

• LRGWUO directed technical committee to develop alternative administrative plan

Foundations for Special Water Users Associations

• Developed by EBID, City of Las Cruces, and the State Engineer

• EBID Policy 2003-GA8, approved November 19, 2003

• 73-10-48 NMSA

SWUAs

• Allow entity to use surface water for M&I and other uses within District boundaries– Ownership of Project Water rights– Lease of Project Water rights– Transfer of Project Water

SWUA Details

• Assessed as EBID constituents• Share pro rata in shortages• Surface water rights maintain EBID’s 1906

priority date• SWUA must lease all of the water from a parcel;

land must be fallowed• Special Combined Unit: Small tracts (<2 acres)

can be consolidated and treated as farm tract for ordering and billing

• Maintained as Ag use until demand for direct M&I use develops

Existing System of Annual Water Transfers

Total Allotment

Agricultural Users

ConservationPool

AgriculturalWater Used

Structure for Transfers of Water to Special Water Users AssociationsTotal

Allotment

Agricultural Users

SWUA

Agricultural Pool

Municipal Pool

AgriculturalWater Used

MunicipalWater

(SWTP)

Conservation Pool:

Leases:Parties

NegotiatePrice

Who Can Form SWUAs?

• Municipalities

• Counties

• State Universities

• Member-owned community systems

• Public utilities

• Interstate Stream Commission

Relationship of SWUAs to AWRM

• SWUAs provide an alternative to strict priority administration– SWUAs allow junior users to move up in

seniority/priority– Common priority date among EBID SWUAs

and irrigators create pro rata sharing of shortages

• Market-driven process