WSP08256

• File Number: 8272.100.60
• Description: Colorado River Basin Salinity Control Forum
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/2002
• Author: CRBSCF
• Title: 2002 Review - Water Quality Standards for Salinity - Colorado River System
• Water Supply Pro - Doc Type: Report/Study

CHAPTER 1 - INTRODUCTION

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Purpose of Report

This report, the 2002 Review. Water Ouality Standards for Salinity. Colorado River System
(Review) is prepared and submitted in response to Section 303( c) of the Clean Water Act5. Prepared
by the seven-state Colorado River Basin Salinity Control Forum (Forum), on behalf of the governors
of their respective states, this Review of the water quality standards includes the numeric criteria and
the Plan of Implementation developed and adopted by the Forum. It also includes modifications to
previous reviews that have become necessary as a result of changed conditions and the availability
of additional information. This is the ninth triennial review conducted by the Forum. Section
303(c)(1) of the Clean Water Act requires that:

The governor of a state or the state water pollution control agency of such state shall
from time to time (but at least once each three-year period beginning with the date
of enactment of the Federal Water Pollution Control Act Amendments of 1972) hold
public hearingsfor the purpose of reviewing applicable water quality standards and,
as appropriate, modifYing and adopting standards. Results of such review shall be
made available to the Administrator.

This Review is consistent with the Environmental Protection Agency (EP A)-approved 1975
standards and deals only with that portion of the Colorado River Basin above Imperial Dam. While
this Review will recap past events in an abridged format, its focus is on information gathered since
issuance of the 1999 Review. Background information and activities regarding historical actions
relative to the development and adoption of salinity standards is contained in the June 1975 standards
report. The prior eight Reviews, from 1978 to 1999, contain more specific information on the eight
3-year periods.

Below Imperial Dam, salinity is controlled as a federal responsibility to meet the terms of the
agreement with Mexico contained within Minute No. 242 of the International Boundary and Water
Commission (IBWC), entitled "Permanent and Definitive Solution to the International Problem of
the Salinity of the Colorado River." Minute No. 242 requires that measures be taken to assure that
Colorado River (River) water delivered to Mexico upstream from Morelos Dam will have an average
annual salinity concentration of no more than liS '"' 30 parts per million (ppm) total dissolved solids
(IDS) higher than the average annual salinity concentration of Colorado River water arriving at
Imperial Dam.

5public Law [P.L.] 92-500 as amended by P.L. 95-217 and P.L. 100-4.

6Water Oualitv Standards for Salinity. Including Numeric Criteria and Plan of Imolementation for Salinity
Control. Colorado River Svstem. Colorado River Basin Salinity Control Forum, June 1975.

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