Wind River Basin (3)
January 2001

Snow
The Wind River basin has below average snow water equivalent (SWE) for this time of the year. SWE in the Wind River above Dubois is 74 percent of average (146 percent of last year). The Little Wind SWE is 51 percent of average water content (147 percent of last year), and the Popo Agie drainage SWE is about 62 percent of average (175 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 66 percent of average (about 151 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
December precipitation in the basin varied from 88 to 210 percent of average. Decenber precipitation for the basin was about 133 percent of average for the 8 reporting stations; that is about 61 percent of last year's amount. Water year-to-date precipitation is 61 percent of normal. The current water-year-to-date average is about 130 percent of last year at this time. Year to date figures range from 167 to 96 percent of average.

Reservoirs
Current storage varies from 70 to 152 percent of average. Bull Lake is currently storing about 62,500 acre feet (41 percent of capacity) -- normally the reservoir is at 58 percent of capacity at this time of the year. Boysen Reservoir is storing about 77 percent of capacity 457,100 acre feet) -- normally the reservoir is at 103 percent of capacity at this time of the year. Pilot Butte is storing 75 percent of capacity (23,600 acre feet) -- normally the reservoir is at 49 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 April through September runoff period. The Wind River above Bull Lake Creek is expected to yield 435,000 acre feet (81 percent of average). Wind River at Riverton will yield about 445,000 acre feet (69 percent of average). Boysen Reservoir inflow will yield about 575,000 acre feet (71 percent of normal). Bull Lake Creek near Lenore is expected to yield about 130,000 acre feet (71 percent of average). Little Popo Agie River near Lander is expected to yield about 33,000 acre feet (64 percent of average). South Fork of Little Wind near Fort Washakie will yield about 60,000 acre feet (74 percent of average). Little Wind River near Riverton will yield about 245,000 acre feet (76 percent of average). 

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - January 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)      APR-SEP       276       371    |      435        81    |       499       594            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       158       329    |      445        69    |       561       732            648
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          APR-SEP       223       433    |      575        71    |       717       927            809
                                                                    |                       |
BULL LAKE CR near Lenore (2)         APR-SEP        75       108    |      130        71    |       152       185            183
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         APR-SEP       7.8        20    |       33        64    |        46        65             52
                                                                    |                       |
SF LT WIND nr Fort Washakie          APR-SEP        30        48    |       60        74    |        72        90             81
                                                                    |                       |
LT WIND RIVER nr Riverton            APR-SEP        74       176    |      245        76    |       314       416            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 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     62.5     95.7     88.8 |   WIND RIVER above Dubios     3       146        74
                                                                        |
BOYSEN                                 596.0    457.1    547.0    613.5 |   LITTLE WIND                 2       147        51
                                                                        |
PILOT BUTTE                             31.6     23.6     23.0     15.5 |   POPO AGIE                   3       175        62
                                                                        |
                                                                        |   WIND above Boysen Resv      7       151        66
                                                                        |
==================================================================================================================================
 * 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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