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,', ~,," -.., 6 lH}1~ t 932 ECOLOGY lAW QUARTERLY [Vol. 28:903 Salinity issues came to a head between the u.s. and Mexico in the early 1960's, when the filling of Lake Powell, combined with the addition of supersaline wastewater from the Wellton- Mohawk Irrigation District in Arizona, drove salt concentrations above 2,000 ppm in the Colorado River as it entered Mexico. 182 The result was a destruction of crops throughout the Mexicali Valley. 183 Two subsequent treaty amendments ultimately guaranteed that Mexico would receive water no more than 115 ppm more saline than the water diverted at Imperial Dam.l84 To meet this requirement, the U.S. implemented salinity control measures, established EPA standards for salinity under the Clean Water Act, re-routed Wellton drain water via canal to the Cienega de Santa Clara, and constructed a $250 million desalinization plant at Yuma which, if necessary, can desalinate Wellton drain water to dilute the mainstream water to prevent violations of the treaty. 185 Unfortunately, these provisions have only provided a temporary solution. Salt concentrations are inversely related to flow levels. As water consumption increases along the Colorado, salinity will rise as water that would otherwise dilute the salinity of the river's water is diverted. Salinity also riSes as water is used and re-used; irrigation retum flows typically contain additional salts leached from the soil.186 Indeed, more than half of the total salt in the river comes from human activities.187 Inevitably, the salt load in the river will grow to unacceptably high levels in Mexico, even if the proportionate levels between Imperial and Morelos dams remain within the treaty limits. 188 The latest report of the Colorado River Basin Salinity Control Forum (CRBSCF) found that some 1.5 million tons of salt must be removed from the river on an annual basis to achieve the treaty standards, at a cost between $27 and $76 per ton. 189 Federal funding for salinity control, however, has been 182. See PONTIUS, supra note 3, at 62. 183. See id. 184. See United States-Mexico Agreement on Colorado River Salinity, Minute No. 242 of the IBWC: Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River, August 30, 1973, U.S.-Mex., reprinted in 68 AM. J. INT'L L. 376, 377 (1974). 185. See Garner, supra note 45, at 500. See also Martin Van Der Werf, Draining the Budget to Desalt the Colorado, HIGH COUNTRY NEWS, February 21, 1994, avaUable at www.hcn.org. 186. See PONTIUS, supra note 3, at 61. 187. See id. at 61-62. 188. Myron B. Holburt, International Problems on the ColOrado River, 6 WATER SUPPLY & MGMT. 105, 111 (1982). 189. SeeNewcom, supra note 178, at 7-8.