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Wyoming Area Office <br />Bureau of Reclamation <br />North Platte River Water Supply Update <br />November 8, 2006 <br />Page 1 of 2 <br />Figure 1 shows current reservoir storage conditions for Reclamation reservoirs as of November <br />5, 2006, on the North Platte River and provides a comparison of total inflow, total Guernsey <br />Reservoir outflow, and total September 30 system storage for water years 2004 through 2006, <br />including the statistical "most probable" 2007 operations complied from the November operating <br />plan. The term "kaf' used in this report represents acre-feet times 1000. The North Platte total <br />system storage of 805.9 kaf at the end of water year 2006 represents a decrease in the system <br />storage of 200.6 kaf over water year 2006 (1006.5 kafl. This system storage decrease is <br />attributable to below average runof£ Irrigation releases from Guernsey Reservoir for <br />downstream irrigation demand were discontinued on September 7, 2006. The North Platte <br />Project Irrigation Districts conserved approximately 328.6 kaf of carryover storage. <br />The total system probable inflow for 2007, which approximates an average inflow condition is <br />estimated to be 1329.7 kaf. The total Guernsey Reservoir probable outflow for 2007 is estimated <br />to be 1164.6 kaf and reflects an assumed full irrigation delivery for the North Platte Project <br />contractors. The projected total system probable storage on September 30, 2007, is estimated to <br />be 56% of average (796.6 kaf/1434.3 kaf) or 29% of the total conservation capacity of the <br />system. <br />Figure 2 and Figure 3 provide snow water equivalent (SWE) information expressed in inches of <br />water for the upper and lower North Platte River basins. This early SNOTEL information shows <br />the SWE is above average for the upper basin and below average for the lower basin. As of <br />November 5, 2006, the Natural Resources Conservation Service (NRCS) reported the SWE to be <br />127% and 94% of average (Figure 4) for the upper and lower basin, respectively. The probable <br />inflow conditions are dependent on late Spring moisture as evidenced by last year when the <br />April 1 snowpack above Seminoe Reservoir was above of average and only produced a April <br />through July runoff of 546.1 AF (78% of average) due to the dry Spring conditions. <br />Table 1 shows the actual total system inflows, Guernsey outflow, and end-of-month total system <br />storage for the month of October and the projected November through September operations <br />based on reasonable minimum, most probable, and reasonable maximum inflow conditions. <br />These statistical inflow conditions provide the range for Reclamation operating plans in the <br />North Platte River Basin. The operating plans are updated monthly to reflect changing inflow <br />conditions. This report focuses on the information associated with the November most probable <br />operating plan. <br />The actual total system inflows for the month of October were 99% of average (49.2 kaf/49.9 <br />ka fl. Table 1 also includes the accompanying information for water year 2006 and the 30-year <br />average (1977-2006) for comparison. Graph 1 through Graph 3 displays this information in <br />graphical format. Based on the November most probable North Platte River Operating Plan, the