Lower North Plate River Basin (9)
March 2001

Snow
SWE for the North Platte River basin in Wyoming averages 79 percent of normal (89 % of last year). The Sweetwater drainage SWE is currently 55 percent (75 percent of last year). Deer and LaPrele Creek SWE is 97 percent of average (104 percent of last year. SWE for the North Platte above the Laramie River drainage is 79 percent of average (89 % of last year). SWE for the Laramie River above Laramie is 77 percent of average (82 % of last year). SWE for the Little Laramie River is 74 percent of average (89 percent of last year). SWE for the Laramie River above the mouth is 77 percent of average (85 % of last year). For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
Of the 11 reporting stations, percentages for the month range from 37 to 190. February precipitation for the basin was 80 percent of average (64 percent of last year). The water year-to-date precipitation for the basin is currently 77 percent of average (92 percent of last year). Year to date percentages range from 46 to 137.

Reservoir
The Lower North Platte River basin reservoir storage is average to well above average. Reservoir storage is as follows: Alcova 156,800 acre feet (100 percent of average); Glendo 326,000 acre feet (85 percent of average); Guernsey 15,300 acre feet (112 percent of average); Pathfinder 753,300 acre feet (128 percent of average); Seminoe 650,500 acre feet (159 percent of average). Wheatland No.2 34,000 acre feet (79 percent of average).. Water allocated to project use is near average with North Platte Project users at 99 percent of average, Kendrick Project users at 119 percent of average, and Glendo Project users at 107 percent of average.

Streamflow
Yields from 61 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 45,000 acre-feet (61 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 96 percent of average (24,000 acre-feet). North Platte River below Guernsey Reservoir is expected to yield about 74 percent of normal (725,000 acre-feet), and below Glendo Reservoir is anticipated to yield about 74 percent of average (705,000 acre-feet). Laramie River near Woods should yield about 72 percent of average (97,000 acre-feet). The Little Laramie near Filmore should produce about 46,000 acre-feet (72 percent of average). 

==================================================================================================================================
                                      LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
                                               Streamflow Forecasts - March 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      15.9        30    |       41        59    |        58        84             69
                                     APR-SEP      17.0        32    |       45        61    |        63        89             74
                                                                    |                       |
Deer Creek at Glenrock               APR-SEP        21        31    |       40       103    |        50        66             39
                                                                    |                       |
La Prele Creek ab La Prele Reservoir APR-SEP       5.6      14.4    |       24        96    |        37        64             25
                                                                    |                       |
Laramie River nr Woods               APR-SEP        50        78    |       97        72    |       124       163            135
                                                                    |                       |
Little Laramie River nr Filmore      APR-SEP        25        38    |       46        72    |        54        67             64
                                                                    |                       |
==================================================================================================================================
          LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS         |  LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
             Reservoir Storage (1000 AF) - End of February              |        Watershed Snowpack Analysis - March 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    156.8    156.1    157.1 |   SWEETWATER                  3        75        55
                                                                        |
GLENDO                                 506.4    326.0    381.8    383.1 |   DEER & LaPRELE CREEKS       4       104        97
                                                                        |
GUERNSEY                                45.6     15.3     15.9     13.6 |   N PLATTE abv Laramie R.    26        89        79
                                                                        |
PATHFINDER                            1016.5    753.3    960.5    590.0 |   LARAMIE RIVER abv Laramie   8        82        77
                                                                        |
SEMINOE                               1016.7    650.5    798.2    409.0 |   LITTLE LARAMIE RIVER        4        89        74
                                                                        |
WHEATLAND #2                            98.9     34.0     70.0     43.2 |   LARAMIE RIVER above mouth  11        85        77
                                                                        |
NORTH PLATTE PROJ                     1062.1    625.4    998.6    633.3 |   NORTH PLATTE               33        89        79
                                                                        |
KENDRICK PROJECT                      1201.7    970.4    989.9    818.1 |
                                                                        |
GLENDO PROJECT USERS                   183.2    136.0    154.7    126.8 |
                                                                        |
==================================================================================================================================
 * 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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