Lower North Platte River Basin (9)
January 2001

Snow
SWE for the North Platte River basin in Wyoming averages 89 percent of normal (140 % of last year). The Sweetwater drainage SWE is currently 70 percent (188 percent of last year). Deer and LaPrele Creek SWE is 120 percent of average (152 percent of last year. SWE for the North Platte above the Laramie River drainage is 89 percent of average (140 % of last year). SWE for the Laramie River above the mouth is 82 percent of average (148 % of last year). SWE for the Laramie River above Laramie is 83 percent of average (141 % of last year). SWE for the Little Laramie River is 78 percent of average (165 percent of last year). For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
Of the 6 reporting stations, percentages for the month range from 0 to 200. December precipitation for the basin was 134 percent of average (148 percent of last year). The water year-to-date precipitation for the basin is currently 90 percent of average (141 percent of last year). Year to date percentages range from 68 to 138.

Reservoir
The Lower North Platte River basin reservoir storage is average to well above average. Reservoir storage is as follows: Alcova 156,400 acre feet (102 percent of average); Glendo 236,800 acre feet (86 percent of average); Guernsey 10,100 acre feet (184 percent of average); Pathfinder 700,500 acre feet (139 percent of average); Seminoe 717,900 acre feet (132 percent of average). Wheatland No.2 did not report. Water allocated to project use is near average with North Platte Project users at 93 percent of average, Kendrick Project users at 119 percent of average, and Glendo Project users at 117 percent of average.

Streamflow
Yields from 80 to 103 percent are expected in the basin during the forecast period. The following yields are based on the fifty percent chance probability runoff for the April through September forecast period. The Sweetwater near Alcova is forecast to yield about 60,000 acre-feet (81 percent of average). Deer Creek at Glenrock is expected to yield about 103 percent of average (40,000 acre-feet). LaPrele Creek above the reservoir is estimated to yield 88 percent of average (22,000 acre-feet). North Platte River below Guernsey Reservoir is expected to yield about 87 percent of normal (860,000 acre-feet), and below Glendo Reservoir is anticipated to yield about 88 percent of average (840,000 acre-feet). Laramie River near Woods should yield about 82 percent of average (110,000 acre-feet). The Little Laramie near Filmore should produce about 54,000 acre-feet (84 percent of average). 

 
==================================================================================================================================
                                      LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
                                               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)
====================================================================|=======================|=====================================
Sweetwater River nr Alcova           APR-JUL      14.3        39    |       55        80    |        72        96             69
                                     APR-SEP      16.3        42    |       60        81    |        78       104             74
                                                                    |                       |
Deer Creek at Glenrock               APR-SEP      16.8        29    |       40       103    |        52        73             39
                                                                    |                       |
La Prele Creek ab La Prele Reservoir APR-SEP       4.1      12.4    |       22        88    |        36        65             25
                                                                    |                       |
North Platte River blw Glendo Reserv APR-JUL       557       713    |      820        89    |       927      1083            925
                                     APR-SEP       562       728    |      840        88    |       952      1118            958
                                                                    |                       |
North Platte River blw Guernsey Resv APR-JUL       502       697    |      830        89    |       963      1158            938
                                     APR-SEP       520       722    |      860        87    |       998      1200            985
                                                                    |                       |
Laramie River nr Woods               APR-SEP        40        82    |      110        82    |       138       180            135
                                                                    |                       |
Little Laramie River nr Filmore      APR-SEP        30        44    |       54        84    |        64        78             64
                                                                    |                       |
==================================================================================================================================
          LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS         |  LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
             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
========================================================================|=========================================================
ALCOVA                                 184.3    156.4    156.8    153.1 |   SWEETWATER                  1       188        70
                                                                        |
GLENDO                                 506.4    236.8    276.4    276.4 |   DEER & LaPRELE CREEKS       2       152       120
                                                                        |
GUERNSEY                                45.6     10.1     10.5      5.5 |   N PLATTE abv Laramie R.    16       140        89
                                                                        |
PATHFINDER                            1016.5    700.5    928.9    505.0 |   LARAMIE RIVER abv Laramie   3       141        83
                                                                        |
SEMINOE                               1016.7    717.9    845.6    542.0 |   LITTLE LARAMIE RIVER        1       165        78
                                                                        |
WHEATLAND #2                                    NO REPORT               |   LARAMIE RIVER above mouth   4       148        82
                                                                        |
NORTH PLATTE PROJ                     1062.1    526.8    899.1    568.4 |   NORTH PLATTE               17       140        89
                                                                        |
KENDRICK PROJECT                      1201.7    972.0    993.6    819.8 |
                                                                        |
GLENDO PROJECT USERS                   183.2    136.5    155.6    116.2 |
                                                                        |
==================================================================================================================================
 * 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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