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<br />uJ22~2 <br /> <br />2005. Surpluses made available under the full M&I surplus tier would only be used for delivery <br />to meet direct use needs in that calendar year and may not be used to refill carryover storage in <br />off-mainstream reservoirs or for groundwater banking programs. <br />4.) Additional Surpluses Based on Space Building to Contain Above-Average Runoff . <br />This tier refers to interim reservoir operating criteria that will allow additional surplus <br />amounts to be made available to create reservoir storage space in anticipation of above normal <br />runoff. A surplus strategy based on enhanced space building criteria was proposed by the Bureau <br />of Reclamation based on studies performed following the 1983 flood events on the Colorado <br />River. In January, 1986, the Bureau issued a special report titled Colorado River - Alterative <br />Operating: Strategies for Distributing Surplus Water and Avoiding: Spills. This report suggested <br />operating strategies for avoiding Lake Mead spills that went beyond the Corps of Engineers flood <br />control criteria, but were, in essence, based on similar principles. Under these criteria, limited <br />surpluses would be determined based on the need to provide adequate storage capacity for an <br />assumed runoff rather than the actual yearly forecast. The Six States propose that the assumed <br />runoff be the value of the 70111 percentile of exceedance based on the historic record which is <br />equivalent to about 17.331 mafrunoff above Lake Powell. Technical studies have named this <br />strategy ''70R.'' <br />In recent years, the Bureau of Reclamation has investigated a number of surplus strategies <br />including "spill avoidance," "flood control avoidance," and "shortage avoidance." All of these <br />methods have positives and negatives associated with them. The Six States believe that the ''70R'' <br />strategy is the best for use during this interim period because any surplus water provided is <br />incremental to the previous tier of a full M&I surplus. In other words, the surplus strategy is not <br />necessary to provide additional water for high value M&I uses since those needs will have already <br />been met. The increment of use that could be available above M&I would likely be for additional <br />groundwater banking and perhaps additional agricultural water in California, Arizona, or Mexico. <br />The Six States do not believe it is prudent to apply surplus strategies that make additional water <br />available based on statistical spill avoidance analysis which will pres~nt a higher risk, if the <br />incremental water benefits are limited to groundwater banking and agricultural purposes. The Six <br />State proposal will make water available for such purposes in years when the ''70R'' strategy <br /> <br />9 <br />