Wind River Basin (3)
May 2000

Snow
The Wind River basin has well below average snow water equivalent (SWE) for this time of the year. SWE in the Wind River above Dubois is 67 percent of average (48 percent of last year). The Little Wind SWE is 40 percent of average water content (22 percent of last year), and the Popo Agie drainage SWE is about 56 percent of average (34 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 58 percent of average (about 37 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
April precipitation in the basin varied from 35 to 126 percent of average. April precipitation for the basin was about 93 percent of average for the 8 reporting stations; that is about 32 percent of last year's amount. Water year-to-date precipitation is 78 percent of normal. The current water- year-to-date average is about 58 percent of last year at this time. Year to date figures range from 57 to 90 percent of average.

Reservoirs
Current storage varies from 83 to 117 percent of average. Bull Lake is currently storing about 93,500 acre feet (62 percent of capacity) -- normally the reservoir is at 53 percent of capacity at this time of the year. Boysen Reservoir is storing about 84 percent of capacity 501,400 acre feet) -- normally the reservoir is at 84 percent of capacity at this time of the year. Pilot Butte is storing 79 percent of capacity (25,000 acre feet) -- normally the reservoir is at 95 percent of capacity at this time of the year.

Streamflow
Water supply is estimated to be below normal this year. The following values reflect the 50 percent chance yields for the May through September runoff period. The Wind River above Bull Lake Creek is expected to yield 450,000 acre feet (88 percent of average). Wind River at Riverton will yield about 470,000 acre feet (77 percent of average). Boysen Reservoir inflow will yield about 530,000 acre feet (70 percent of normal). Bull Lake Creek near Lenore is expected to yield about 140,000 acre feet (78 percent of average). Little Popo Agie River near Lander is expected to yield about 20,000 acre feet (41 percent of average). South Fork of Little Wind near Fort Washakie will yield about 54,000 acre feet (69 percent of average). Little Wind River near Riverton will yield about 160,000 acre feet (53 percent of average).

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - May 1, 2000
==================================================================================================================================
                                              |  <<====== Drier ======  Future Conditions  =======  Wetter =====>>  |             
                                              |                                                                     |
  Forecast Point                     Forecast |  ==================== Chance Of Exceeding * ======================  |
                                      Period  |    90%       70%    |  50% (Most Probable)  |      30%       10%    |  30-Yr Avg.
                                              | (1000AF)  (1000AF)  |   (1000AF)  (% AVG.)  |    (1000AF)  (1000AF) |    (1000AF)
====================================================================|=======================|=====================================
WIND RIVER abv Bull Lake Cr (2)      MAY-SEP       374       419    |      450        88    |       481       526            511
                                                                    |                       |
WIND RIVER at Riverton (2)           MAY-SEP       292       398    |      470        77    |       542       648            609
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          MAY-SEP       271       425    |      530        70    |       635       789            758
                                                                    |                       |
BULL LAKE CR near Lenore (2)         MAY-SEP       111       128    |      140        78    |       152       169            179
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         MAY-SEP       6.3      14.4    |       20        41    |        26        34             49
                                                                    |                       |
SF LT WIND nr Fort Washakie          MAY-SEP        34        46    |       54        69    |        62        74             78
                                                                    |                       |
LT WIND RIVER nr Riverton            MAY-SEP        42       112    |      160        53    |       208       278            303
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of April                 |        Watershed Snowpack Analysis - May 1, 2000
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
BULL LAKE                              151.8     93.5     99.9     79.9 |   WIND RIVER above Dubios     6        52        67
                                                                        |
BOYSEN                                 596.0    501.4    474.8    502.6 |   LITTLE WIND                 2        22        40
                                                                        |
PILOT BUTTE                             31.6     25.0     19.2     30.1 |   POPO AGIE                   5        38        56
                                                                        |
                                                                        |   WIND above Boysen Resv     12        39        58
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table.

The average is computed for the 1961-1990 base period.

(1) - The values listed under the 10% and 90% Chance of Exceeding are actually 5% and 95% exceedance levels.                  
(2) - The value is natural volume - actual volume may be affected by upstream water management.


	BIGHORN RIVER BASIN as of May 1, 2000

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