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Stream Flow Statistics for High, Low, and Normal or Average Stream Flow Years

 
 

High, low, and normal or average stream flow conditions were determined for each of the seven subbasins of the Platte River Basin. Stream flow gauges within the North and South Platte River Basins in Wyoming were located using the resources of the United States Geologic Survey (USGS), Wyoming State EngineerÆs Office (SEO), and the Water Resources Data Systems (WRDS) library. Stream flow gauge data were then compiled to determine high, low, and average or normal annual flow years for each of the Platte Basin subbasins.

The process to determine and assess stream flow included:

  • Identifying North and South Platte River stream flow gauges located in Wyoming that are not influenced by major reservoir operations and collecting gauge data;
  • Selecting a potential period of study;
  • Determining if the selected period of study satisfactorily represented the long term;
  • Selecting representative index stream flow gauges for each subbasin within Wyoming's Platte River Basin; and
  • Compiling and processing index stream flow gauge data to compare high, low, and normal or average stream flow years in each subbasin.

The "high flow year" designation was assigned to years having total annual gauged flows in the highest 20th percentile during the 1972 through 2001 study period or to the years having the highest annual flows followed by a significant decrease in annual flow. The "low flow year" designation was assigned to years having total annual gauged flows in the lowest 20th percentile during the study period. The "normal or average year" designation was assigned to the remaining years during the study period.

The representative stream flow gauges in the Upper Laramie River subbasin from which data were collected and assessed included:

  • Laramie River / Pioneer Canal near Woods Landing- #6659500
  • Little Laramie River near Filmore - #661000

Click here to view a map of the representative stream flow gauges in the Upper Laramie River subbasin.

The following table summarizes the Upper Laramie River subbasin high, low, and normal stream flow years during the study period. Note that stream flow volumes may be used only to determine high, low, and normal or average stream flow years; composite stream flow volumes shown below do not indicate actual flows at any point in the subbasin.

Summary of representative annual high stream flow, low stream flow, and normal or average stream flow in the Upper Laramie subbasin

No.
Year
Annual stream flow (acre-feet)
1
1983
219,777
2
1986
174,174
3
1984
164,824
4
1997
132,272
5
1973
131,131
6
1979
130,758
7
1996
126,012
8
1982
125,461
9
1995
119,742
10
1978
118,509
11
1980
117,739
12
1974
116,484
13
1999
106,078
14
1993
103,456
15
1985
100,449
16
1988
96,117
17
1975
95,688
18
1998
91,178
19
1972
86,138
20
1976
73,479
21
1990
72,448
22
2000
72,177
23
1991
70,551
24
1994
58,954
25
1992
58,345
26
2001
50,915
27
1987
47,407
28
1981
46,461
29
1977
44,029
30
1989
41,443
  Indicates high flow year and flow volume
  Indicates low flow year and flow volume
Years and annual flows which are neither shaded or outlined are normal or average stream flow years and flows.
 
 


The Platte River Basin Plan is a planning tool developed for the Wyoming Water Development Office. It presents estimated current and estimated future uses of water in WyomingÆs Platte River Basin. The Plan is not used to determine compliance with or administration of state law, federal law, court decrees, interstate compacts, or interstate agreements.
Wyoming Water Development Commission
6920 Yellowtail Road
Cheyenne, Wyoming 82002
Ph. (307) 777-7626
Fax (307) 777-6819