WSP03527

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/2003
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

I

I

I
I
I
I

Measures that are being taken to ensure that the salinity differential requirements at >:IB will be met
include reducing drainage pumping in the South Gila Valley in areas with more than adequate depths
to groundwater. returning some drainage flows from the Yuma Mesa Conduit to the Yuma Valley
Drainage System and thence to the boundary pumping plant at the Southerly International Boundary
with :-.texico. and ensuring that no additional drainage water from the ~10DE will be spilled to the
Colorado River this calendar year. This action is required as several Yuma Valley Drainage wells
that used to discharge 10 the SIB have been connected to the Yuma :-'1esa Conduit. causing salinitv
" " "
levels at the ~IB to increase as the quantity of drainage inflow to the Colorado River above NIB
increases. At the same time. better quality water has been arriving at Imperial Dam since CY 2000.
These two issues combined together are currently resuhing in a forecast salinity differential near the
maximum allowed under .\1inute 242.

I
I

Located at the Yuma Desalting Plant is a research facility known as the Water Quality Improvemcnt
Center (WQIC). The primary role of the WQIC is to find \vays to reduce operating costs of the '{DP.
To do this. Reclamation personnel \vho work in the \VQIC investigate new technologies and
processes. and explore improvements in operational and maintenance efficiencies. The WQIC also
serves as a key component in Reclamation's Technology Transfer program - hosting third party
research to enhance the spread of publicly-developed water treatment technology into private
industry. This prob'Tam serves Reclamation in two ways: it reduces the overall cost ofYDP cost-
reduction research by attracting outside parties pursuing similar interests; and it hclps guarantee
additional water supplies by supporting the proliferation of water. stretching trcatment technology
throughout the U.S. In addition. the WQIC serves as the primary water provider to the Yuma Area
Office. The facility purifies about one million gallons per day of either drainage water delivered
either from the rv10DE. groundwater pumped from an on-site well, or Colorado Ri\'er water. The
WQIC will continue to operate during calendar year 2003.

I
I

I

I
I

Colorado RiHr Channel Aggradation Below Gila Ri\"Cr Confluence

I
I

The 1993 Gila River flood deposited approximately 10 million cubic yards of sediment in the
Colorado River between its confluence with the Gila and Morelos Dam. An additional unspecified
volume of sediment was deposited in the river channel below .\10relos Dam. The aggradation of the
channel has substantially reduced the river's capability to carry flood flo\I,'s, to act as a drain for
groundwater, and has occasionally caused operational problems with the delivery of Treaty water to
Mexico at ~1orelos Dam.

The )"uma Area Office developed a project proposal to addrcss the aggradation problems in
cooperation with local irrigation districts. the IBWC Native American Tribes. local environmental
organizations. local governments, and other state and federal agencies.

I
I

The overall project has been developed in phases. Phase 1 of the project was completed in late 1997
so the channel below :-'lorelos Dam could accommodate flood control releases from Hoover Dam
during the winters of 1997 and 1998. Phase 1 consisted of limited clearing of a flow path in the
channel below ~lorelos Dam. and realignment of the channel upstream of Yuma at River :-"Iile 31,
where thc levee was in danger of being breached during high flows.

I

December 13. 2001

20

I