Wind River Basin (3)
June 2001

Snow
The Wind River basin has much much below average snow water equivalent (SWE) for this time of the year. All snow has melted form the SNOTEL sites in this basin. Some snow is found at the higher elevations (above elevation 10,000).

Precipitation
May precipitation in the basin varied from 2 to 96 percent of average. May precipitation for the basin was about 64 percent of average for the 9 reporting stations; that is about 60 percent of last year's amount. Water year-to-date precipitation is 58 percent of normal. The current water-year-to-date average is about 71 percent of last year at this time. Year to date figures range from 49 to 79 percent of average.

Reservoirs
Current usable storage varies from 58 to 86 percent of average. Bull Lake is currently storing about 79,500 acre feet (52 percent of capacity) -- the reservoir is at 77 percent of average at this time of the year. Boysen Reservoir is storing about 69 percent of capacity (413,900 acre feet) -- the reservoir is at 86 percent of average for this time of the year. Pilot Butte is storing 47 percent of capacity (14,700 acre feet) -- the reservoir is at 58 percent of average for this time of the year.

Streamflow
Water supply is estimated to be much below normal this year. Irrigation water shortages can be expected in this drainage basin. The following values reflect the 50 percent chance yields for the June through September runoff period. The Wind River above Bull Lake Creek is expected to yield 170,000 acre feet (41 percent of average). Wind River at Riverton will yield about 100,000 acre feet (20 percent of average). Boysen Reservoir inflow will yield about 175,000 acre feet (29 percent of normal). Bull Lake Creek near Lenore is expected to yield about 55,000 acre feet (36 percent of average). Little Popo Agie River near Lander is expected to yield about 6,500 acre feet (18 percent of average). South Fork of Little Wind near Fort Washakie will yield about 20,000 acre feet (32 percent of average). Little Wind River near Riverton will yield about 45,000 acre feet (19 percent of average).

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - June 1, 2001
==================================================================================================================================
                                              |  <<====== 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)      JUN-SEP       155       164    |      170        41    |       185       206            420
                                                                    |                       |
WIND RIVER at Riverton (2)           JUN-SEP        76        90    |      100        20    |       149       220            505
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          JUN-SEP       115       151    |      175        29    |       259       382            609
                                                                    |                       |
BULL LAKE CR near Lenore (2)         JUN-SEP        50        53    |       55        36    |        61        70            154
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         JUN-SEP       5.7       6.2    |      6.5        18    |       8.4      11.2             37
                                                                    |                       |
SF LT WIND nr Fort Washakie          JUN-SEP      17.8      19.1    |       20        32    |        23        27             63
                                                                    |                       |
LT WIND RIVER nr Riverton            JUN-SEP        38        42    |       45        19    |        60        83            241
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 1, 2001
==================================================================================================================================
                                      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     79.5    112.9     92.7 |   WIND RIVER above Dubios     3         0         0
                                                                        |
BOYSEN                                 596.0    413.9    542.9    546.4 |   LITTLE WIND                 2         0         0
                                                                        |
PILOT BUTTE                             31.6     14.7     24.5     25.5 |   POPO AGIE                   3         0         0
                                                                        |
                                                                        |   WIND above Boysen Resv      7         0         0
                                                                        |
==================================================================================================================================
 * 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.


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