PRRIP North Platte 04/20/2010

• Description: Related to the Platte River Recovery Implementation Program
• State: NE
• State: WY
• State: CO
• Basin: North Platte
• Basin: South Platte
• Water Division: 1
• Date: 4/20/2010
• Author: Various
• Title: PRRIP EAC/RCC April 20 2010 Meeting
• Water Supply Pro - Doc Type: Meeting

Wyoming Area Office
Bureau of Reclamation
North Platte River Water Supply Update
April 20, 2010
Page 1 of 2
Figure 1 shows current reservoir storage conditions for Reclamation reservoirs as of April 18,
2010, on the Not Platte River and provides a comparison of total inflow, total Guernsey
Reservoir outflow, and total September 30 system storage for water years 2006 through 2009,
including the "expected" 2010 operations compiled from the April operating plan. The term
"kafl' used in this report represents acre -feet times 1000. The North Platte total system storage
of 1700.4 kaf at the end of water year 2009 represents an increase in the system storage of 504.6
kaf over water year 2008 (1195.8 kaf). This system storage increase is attributable to above
average snowmelt runoff in the upper and lower North Platte Basins. The month of June 2010
experienced above average precipitation and below average temperatures, which resulted in a
release of only 25.0 kaf from Guernsey Reservoir for the month (15% of average). Irrigation
releases from Guernsey Reservoir for downstream irrigation demand were discontinued on
September 21, 2009. The North Platte Project Irrigation Districts conserved approximately
555.4 kaf of carryover storage.
The total system expected inflow for 2010 is estimated at 1,230.6 kaf or 92% of average. The
total Guernsey Reservoir expected outflow for 2010 is estimated to be 988.9 kaf. The projected
total system expected storage on September 30, 2010, is estimated to be 122% of average
(1723.3 kaf /1410.6 kaf) or 62% of the total conservation capacity of the system.
Figure 2 and Figure 3 provide snow water equivalent (SWE) information expressed in inches of
water for the upper and lower North Platte River basins. The SNOTEL information shows the
SWE is below average for the upper and lower North Platte River Basin. As of April 18, 2010,
the Natural Resources Conservation Service (MRCS) reported the SWE to be 93% and 97% of
average (Figure 4) for the upper and lower basin, respectively. Reclamation's April 1 forecast of
the April through July runoff in the basin above Seminoe Reservoir is 650 kaf (92% of average)
and 120 kaf (96% of average) for the basin between Alcova and Glendo Reservoirs. Figure 2
and Figure 3 show a comparison of the SWE curves for 2007 through 2010. Reclamation's
determination of the forecasted supply as of April 1 is above 1,100 kaf (Figure 5), which
indicates at this time there is no need to allocate storage.
Table 1 shows the actual total system inflows, Guernsey outflow, and end -of -month total system
storage for the month of October through March and the projected April through September
operations based on minimum, expected, and maximum inflow conditions. These inflow
conditions (Table 2) provide the range for Reclamation operating plans in the North Platte River
Basin. The operating plans are updated monthly to reflect changing inflow conditions. This
report focuses on the information associated with the April expected operating plan.