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854 NATURAL RESOURCES JOURNAL [Vol. 40 Fall 2000] MANAGING ECOSYSTEM CONSERV ATlON 855 any surplus, as well as before ~y off-stream ~tor~ge us~s. If and when the Department of Interior formalizes shortage crlterl~, env~o~ental groups will demand that baseline flows for the Delta receive pnonty as well. 3. Salton Sea Several proposals to improve the ecological conditions of California's Salton Sea, a large inland saline lake fed by agricultural drainage and lying in a former arm of the Colorado delta, would l~ ~e Sea to the current limit of the Delta and its estuary. To reduce and stabillZe the salinity and elevation of the Salton Sea, resource managers have proposed several alternatives, including pumping Salton Sea water to the Gulf of Califomia.163 Any consideration of management options involving discharge of Salton Sea water to the Delta or Gulf of Cali~omia will ~equire Mexican involvement, and thus may present an opportunity for MeXIco and the United States to consider binational measures for enhancing Delta ecosystems. 164 Another Salton Sea restoration proposal would have diverted up to 300,000 acre-feet of Colorado River floo~ fl~~s from ~e '?~~tem at Imperial Dam in Arizona to the Salton Sea, slgnificantly dunuushing the quantity of water that would otherwise reach the Delta.l65 Were the effluent and wastewater now flowing into the Salton Sea managed with care in the Delta, they might bring some benefit to wetland ecosystems. For example, flood flows could flush awa~ any b.ui1~up of pollutants or salinity. A new wastewater treatment plant m MeXIcah-to be completed in2001-will improve the quality of some of the effluent now sent via the New River to the Salton Sea. The plant is presently designed to discharge treated effluent into the New River and eventually empty into the Salton Sea. If instead this treated effluent is discharged into the Rio Hardy basin, the Rio Hardy wetlands might serve as part of the wastewater treatment process. Both the Mexican government and the U.S. EPA have indicated an interest in exploring options for using treated water to enhance Delta environments.l66 4. Yuma Desalting Plant A proposal by the BOR to operate the Yuma Desalting Plant167 and market the resulting water would divert agricultural wastewater flows from the Cienega de Santa Clara and replace the wastewater with concentrated brine.l68 The basin states are likely to increase pressure on the BaR to operate the plant in order to treat the MODE canal water to Minute 242 salinity standards. In this way agricultural wastewater could be counted ~s treaty water, freeing a like amount of upstream water for use by the basm states.169 Operating the Desalting Plant would markedly reduce the area of the Delta wetlands and negatively impact wildlife and local.residents who generate income as wildlife guides. A decision to operate the Desalting Plant will require an environmental assessment. In order to prevent damage to the Delta ecosystem, water supplemental to Mexico's Colorado River entitlements must be dedicated to support the Cienega de Santa Clara. 5. All-American Canal and Delivery a/Water to Mexico Mexico relies on groundwater pumped from border region aquifers to augment its supplies,170 but plans by California and Nevada to line the nearby All-American Canal will lower the water table in these aquifers.171 Mexico opposes these plans on the grounds that the seepage from the canal is" grandfathered"l72-in other words, a known condition that existed at ~e time the original treaty was negotiated, and, therefore, water to which Mexico is entitled. In addition, Mexico has requested that its entire allocation of water from the Colorado River be delivered at the Northerly c;:. c' w W I. .. ~ 167. See supra note 43. 168. Telephone interview with RobertJohnson, Regional Director, Lower Colorado Region Office, U.S. Bureau of Reclamation Oan. 2000). 169. Atpresent, 110,000 acre-feet of saline agricultural wastewater flows to the Cienega de Santa Clara annually, sustaining 50,000 aaes of wet1and habitat See discussion infra Section II. Despite the inadvertent nature of the Cienega's aeatio~ any proposal ~t resullll in.illl destruction or degradation is certain to be challenged by envIrOnmental groups U\ both MexiCO and the United. States. 170. Mexico pumps approximately 100,000 acre-feet of groundwater per year that is directly attributable to seepage loss from the All-American Canal. See Douglas L. Hayes, The All-AmeriCJJn CatIJIl Uning Project: A Catalyst for RationRl and Comprehensive Groundwater MalUlgement on the United States-Mexico Border 31 NAT. REsoURCES. J. 803, 805 (1991). 171. The Bureau of Reclamation estimates that the 29.9 mile reach of the All-American Canal from PUot Knob to Drop 4 loses 91,600 acre-feet per year, most of which recharges the shallow aquifer in the northeast section of the Mexicall Valley. When the Canal is lined, groundwater depths are projected to drop from o~ to 30 feet ~ a 70 sq~ mile region. o~er SO years. See U.S. Bureau of Reclamation, U.S. Dep t of the Intenor, All Amer1Can Canal Lining project: Imperial County California: Final Environmental Impact Statement/Final Environmental Impact Report, at m-4, m-s (1994), 172. See Hayes, SUprll note 170, at 806. 163. See Tetra Tech, Inc., SlIlton Sell Restoration Project Environmental Impact Statement/ Environmental Impact Report at 2-43,6-27 to 6-34 (2000) (unpublished draft prepared for Salton Sea Restoration Authority &t: U.S. Bureau of Reclamation),lIwilRble lit <http://www.lc.usbr. gov I-saltnseal deistoc.html>. 164. The transfer of Salton Sea water to Delta wetlands may inaease pollutanlll and salinity in the Delta and adversely affect Delta wildlife. 165. See Tetra Tech. Inc., supra note 163 at 2-27, ~27 to ~29. 166. Telephone interview with Doug Eberhardt, Environmental Engineer, Water Management Division, U.S. Environmental Protection Agency RegionlX aul. 1999); Tele~~ne interview with Carlos Pet\a, Division Engineer, International Boundary and Water COI1'll1USSIOn (Apr. 1999).