WSP05341

• File Number: 8278.100
• Description: Title I - Yuma Desalting Plant
• Basin: Colorado Mainstem
• Date: 12/23/1992
• Author: USDOI/BOR
• Title: Yuma Desalting Plant - Alternatives for the Interim Period
• Water Supply Pro - Doc Type: Publication

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

operation; (3) the Bypass Drain from Morelos Dam to the Slough to
dispose of reject stream from the Desalting Plant and other bypassed
water; (4) concrete lining of the first 49 miles of the Coachella Canal
in California to conserve water and, therefore, replace bypassed WMIDD
drainage flows during an interim period while the Desalting Plant was
under construction and prior to any required reductions in Colorado
River water deliveries to water users within the State of California;
and (5) a well field in Arizona known as the Protective and Regulatory
Pumping Unit (PRPU), which recovers ground water and combines it with
irrigation drainage flow to annually deliver up to 140,000 af of water
at the Southerly International Boundary with Mexico.

YUMA DESALTING PLANT

Location

The Desalting Plant, a central feature of the works authorized by
Title I, is located on a 60-acre tract of land 6 miles west of Yuma,
Arizona.

Sizing and Performance

Public Law 93-320 authorized construction of a desalting plant with a
129 million-gallon per day (Mgaljd) capacity. However, a 19772 sizing
study recommended construction of a 96 Mgaljd desalting plant with the
"operational characteristics for a reverse osmosis desalting process
'" calJable of recovering 70 percent of the plant feed water." Using
the criteria establishe~ in the 1977 study, contracts specifying a total
treatment capacity of about 96 Mgaljd were awarded to two manufacturers
of reverse osmosis desalting equipment.

However, by 1979, the WMIDD irrigation drainage reduction program was
proving so successful that irrigation drainage was projected to be
eventually reduced to 108,000 af per year. As a result, the required
capacity of the Desalting Plant was further reduced to 72.4 Mgaljd, and
a new plan was developed based on the premise of staged desalting plant
construction. That is, the 96 Mgal/d design was completed, but specific
increments of capacity (solids contact reactors (SCRs), filters, and
associated equipment) in construction were deleted. This approach was
less costly than redesigning the Desalting Plant.

Desalting Process

The Desalting Plant is divided into two distinct systems: (1) the
partial lime softening pretreatment system; and (2) the reverse osmosis
desalting system.

2 Colorado River Basin Salinity Control Project, Title I Division,
Desalting Complex Unit, Sizing Study, Yuma Desalting Plant, Arizona,
Interim Report, June 1977, Lower Colorado Region, Bureau of Reclamation.

5