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Agenda Item 28 May 16-17,2006 Board Meeting Page 3 of4 . does not necessarily change, but the annual evaporation calculation does allow for a shift in how the depletion occurs by allowing it to be used for human needs as opposed to being evaporated. . It utilizes an updated future depletion schedule. Updating the depletion schedule to reflect the fact that development is not occurring at the rate anticipated allows the time a contract can reasonably be expected to be met to be extended. New Mexico and the USBR after extensive analysis are proposing a HD of 5.76 maf exclusive of CRSP shared reservoir evaporation as shown in the attached model run. The yield to Upper Basin is 6.265 maf when shared CRSP evaporation of 505,400 AF is added to the 5.76 maf HD. The major model assumptions used are displayed in the upper right hand corner of the attached spreadsheet and are briefly summarized as follows: . Active Powell, Flaming Gorge, Navajo and Aspinall Unit storage plus live storage in 60 other Upper Basin Reservoirs is used. . Bank storage equal to 4% oflive storage capacity is used. . Sedimentation at the rate shown is deducted through 2060 to arrive at the adjusted storage amount for the model run. . Lower Basin delivery is 8.25 maf if the natural flow at Lee Ferry exceeds or is equal to this amount, if the natural flow at Lee Ferry does not equal or exceed 8.25 maf (which situation occurs in 1934 and 1977), deliveries are limited to the amount available. The Lower Basin delivery under this assumption averages 8.20 mar, excluding spills, over the period 1906-2000 and 8.15 maf for the critical period. The cumulative shortage amount computed in the attached run is 3.54 maf and in total is less than the amount of the CRSP minimwn power pool contents, thus the cwnulative shortage or the shortage in any given year is to power and is not a curtailment of Upper Basin uses. . Discussion A HD of 5.76 maf exclusive of CRSP shared reservoir evaporation would allow the Navajo- Gallup Water Supply Project to proceed in accord with the Congressional requirements and the Navajo Settlement Agreement. The 5.76 maf HD means that New Mexico uses would occur within its compact apportionment and therefore likely would not be subject to the advance repayment provisions in Article N(b) of the Upper Colorado River Compact. Rather New Mexico would simply absorb their proportionate share of any curtailments required under Upper Colorado River Compact. . In March 2005, the Board discussed the issue of whether or not the Settlement actually kept New Mexico within its compact apportionment under the 1988 HD. The Settlement agreements appeared to accomplish that goal. However, New Mexico was advancing a depletion schedule that assumed that 5% of the irrigated land is fallow at any given point in time. If this did not occur, New Mexico would rely on certain subordination clauses in the Settlement to remain within their compact apportionment. Accounting details on how that would be done have not yet been worked out. This apportionment concern was compounded by acknowledging that individual members of the Navajo Nation that have been allotted land by the U.S. are not bound by the Settlement and may have additional claims that would have to be "offset" by corresponding reductions in use by the Navajo Nation as a whole that are now required under the Settlement. The updated HD helps address these concerns. Flood Protection. Water Project Planning and Finance. Stream and Lake Protection Water Supply Protection. Conservation Planning