WSP11096

• File Number: 8273.100
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/1998
• Title: Salinity Management Study - Final Report - DRAFT - June 1998 - Part 1 of 2 - Title Page through
• Water Supply Pro - Doc Type: Report/Study

USBRIMWD SALINITY MANAGEMENT STUDY
FINAL REPORT

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Metropolitan is actively working through the CALFED process, and through its role as a
SWP contractor, to monitor and support actions which would reduce the salinity content of
SWP water. Current TDS objectives cited in the State Water Service Contracts are listed in
Table 2-3. Technical Appendix 2 provides additional infonnation regarding SWP salinity.

.

Table 2-3 Current TDS Ob' ectives for SWP

TDS
Chlorides

440
110

220
55

Constituent Monthl Avera e m fL to-Year Avera e m fL

PERCHLORATE

Perchlorate, a salt which has recently been detected in local groundwater and Colorado Rive
water, is presenting an emerging water quality issue. Perchlorate (as ammonium perchlorate)
is an inorganic chemical used in the production of solid rocket fuels, munitions, and fireworks.
It is a commercial product that does not exist naturally in the environment.

The California Department of Health Services (CDHS) has adopted an action level for
perchlorate in drinking water of 18 micrograms per liter. CDHS recommends that utilities e
monitor their water supplies and take the supply out-of-service if the concentration of
perchlorate exceeds the action level. The analytical reporting limit is 5 micrograms per liter.
Since 1997, perchlorate has been detected statewide in 11 0 domestic water wells in areas
where aerospace material and munitions development, testing, and manufacturing occurred.
Thirty-three of those wells have exceeded the state's action level and twenty-two wells have
been closed. The remaining wells are blended with other sources to comply with the action
level criteria of the CDHS.

Perchlorate has been detected in Metropolitan's Colorado River water source at
concentrations ranging from 5 to 9 micrograms per liter. SWP water does not have detectable
levels of perchlorate. The contamination in Colorado River water has been traced to
perchlorate-based manufacturing in the Las Vegas/Henderson, Nevada area. The
manufacturers are cooperating with the Nevada Division of Environmental Protection to
characterize the extent of the contamination and provide containment and treatment. In
general, because perchlorate is a chemically conservative substance that behaves in water
similarly to salinity, measures to mitigate IDS in CRA water will serve to reduce perchlorate
concentrations as well.

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BOOKMAN-EDMONSTON Section 2

EN GIN E E R IN G, IN c. 2-16 Salinity Problems, Impacts, & Technology
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