WSP03864 - Laserfiche WebLink

Home Browse Search

. c) >I'" 01 ~;::.... . . United States Geological Survey Colorado River Basin Salinity Control Program Accomplishments for Fiscal Year 1997 Arizona Well Inventory of the Lower Colorado River Flood Plain and Adjacent Areas in Arizona, California, Nevada, and Utah The U.S. Supreme Court decree, 1964, Arizona, v. California. is specific about the responsibility of the Secretary of the Interior to account for consumptive use of water from the mainstream; consumptive use is defined to include "water drawn from the mainstream by underground pumping." Water pumped from wells on the flood plain is presumed to be Colorado River water and the accounting surface can be used to identify wells outside the flood . plain in and near the lower Colorado River valley that yield water that will be replaced by water from the river. The objective of this cooperative project between the U.S. Geological Survey and the Bureau of Reclamation is to inventory wells on the lower Colorado River flood plain and adjacent areas in Arizona, California, Nevada, and Utah. Work on the project began in April 1994 to locate wells, provide current information for each well, and provide precise position information in order to apply the accounting-surface method and include the appropriate wells in water accounting along the river. Water levels are required where possible for all wells in areas adjacent to the flood plain. Over 1.000 wells have been inventoried in the Yuma area and southeast Imperial Valley and over 1300 wells have been inventoried on and near the Colorado River and Chemehuevi Indian Reservations and in Palo Verde and Cibola Valleys. The inventory has been expanded to include river pumps; about 180 river pumps have been inventoried. Data on over 1300 wells and river pumps in Arizona and California have been entered into the U.S. Geological Survey data bases. Determination of the Extent of the River Aquifer in the Lower Colorado River Valley near Yuma, Yuma County, Arizona, and Imperial County, California The U.S. Supreme Court decree, 1964, Arizona v. California, requires the identification of the users of Colorado River water and publication of the quantities of diversion and consumptive use stated for each diverter, point of diversion, and State. To aid in implementing the court decision, the extent of the river aquifer must be determined as part of the method to identify wells downstream from Laguna Dam that yield water that will be replaced by water from the Colorado River. Particular areas of concern in delineating the boundary are in southeastern Imperial County, California, from the northerly international boundary with Mexico to the Chocolate Mountains and in Yuma County, Arizona, between the Gila and Laguna Mountains. The objectives of this cooperative project between the U.S. Geological Survey and the Bureau of Reclamation are to (1) use gravity studies to determine the extent and thickness of the sediments and sedimentary rocks of the river aquifer between the northerly international boundary and the Chocolate Mountains and between the Gila and Laguna Mountains, (2) prepare maps and associated geographic information system coverages that show the river-aquifer boundary, geology, and study-area boundary to match the maps created for the 6 "_......" c,..- ,,;~;_.c.;. J;' .: .~.