|
<br />
<br />1111 SOlUTION I:
<br />
<br />,{
<br />
<br />i
<br />;<' <~
<br />
<br />I'\)
<br />c.J1
<br />...J
<br />w
<br />
<br />costs. AgrIcultural losses (either
<br />through lower yields or higher
<br />production/management costs)
<br />begin when salinity levels of
<br />applied irrigation water reach 700 to
<br />850 mg/L, depending upon soil
<br />conditions and type of crop grown.
<br />
<br />In the late 1960's and early
<br />1970's, leaders at the regional and
<br />national levels began to recognize
<br />the total problem and to seek
<br />comprehensive solutions.
<br />
<br />THE SOLUTION
<br />
<br />In 1972, an amendment to the
<br />Federal Water Pollution Control
<br />Act, Public Law 92-500 (now known
<br />commonly as the Clean Water Act),
<br />sets forth a public policy embracing
<br />the restoration and maintenance of
<br />water quality, pollution effluent
<br />discharge limitation, and eventual
<br />zero pollution discharge, EP A
<br />interpreted the Act to require water
<br />quality standards, including bene-
<br />ficial use designations, numeric
<br />salinity crIteria, and a plan of imple-
<br />mentation for the Colorado River,
<br />Numeric criteria were subsequently
<br />established at three stations by the
<br />Colorado River Basin Salinity
<br />Control Forum (Forum), The
<br />crIteria and a plan of implementa-
<br />tion were adopted by each of the
<br />Basin States and approved by EP A,
<br />The criteria, set in terms of
<br />milligrams per liter of IDS, are
<br />shown in the following tabulation,
<br />
<br />Location
<br />
<br />Annualflow- ".. .'
<br />weighted averag~" "
<br />TDS(mll'/Ll ~, 1
<br />~
<br />'J
<br />i
<br />I
<br />l
<br />"
<br />1
<br />"
<br />"
<br />
<br />Below Hoover Dam
<br />Below Parker Dam
<br />Below Imperial Dam
<br />
<br />723
<br />747
<br />879
<br />
<br />To meet these criteria, under
<br />future conditions, approximately
<br />1.0 million tons of salt annually will
<br />need to be removed from the rIver's
<br />waters, The overall strategy in
<br />meeting the standard$ is to prevent
<br />salt from entering and mixing with
<br />the rIver's flow, A number of
<br />agricultural, point, an~ diffuse
<br />sources of salinity have helm
<br />identified throughout the Basin,
<br />The salinity control program will
<br />implement controls at those sItes
<br />which contain salt sowces that can
<br />be intercepted, reduced, and/or
<br />prevented from entering the river at
<br />least cost,
<br />
<br />'I
<br />11
<br />,
<br />J
<br />I
<br />:~
<br />
<br />
<br />:i
<br />.,
<br />,I
<br />>~
<br />"
<br />>1
<br />:1
<br />,;1
<br />,
<br />;l
<br />'j
<br />J
<br />'.J
<br />l
<br />j
<br />4
<br />)
<br />,4
<br />.,
<br />:1
<br />,
<br />A
<br />.,
<br />1
<br />I
<br />,
<br />"'I
<br />
<br />In June 1974, Congtess enacted
<br />the Colorado River Basin Salinity ,
<br />Control Act, Public Law 93~20,
<br />which directed the Se<iretary of the
<br />InterIor to proceed with a program
<br />to enhance and proted the quality of
<br />water available in the Colorado
<br />River for use in the Urilted States
<br />and the Republic of Mexico,
<br />
<br />~
<br />Title I of Public Law 93-320 ;:
<br />enables the United States to, comply .:J' :J
<br />with its obligations under tlje .;
<br />agreement with Mexico dated :, .:1
<br />August 30, 1973 (Minute No, 242 of ~
<br />the International Boundary and .J
<br />
<br />'.1
<br />
<br />.f
<br />
|