Prepared by the U.S. Geological Survey in cooperation with the North Dakota State Water Commission
Figure 1. Location of the Devils Lake Basin. (Postcript Version)
Since glaciation, the lake level of Devils Lake has fluctuated from about
1,457.0 feet above sea level, the natural spill elevation of the lake, to about
1,400.0 feet above sea level (Aronow, 1957). No documented records of lake
levels are available before 1867, but, on the basis of tree-ring chronology,
Upham (1895, p. 595) indicated that the lake level of Devils Lake was 1,441.0
feet above sea level in 1830. Lake levels were recorded sporadically from 1867
to 1901, when the USGS established a gaging station on Devils Lake. For the
period 1867 to the present (1995), the lake level reached a maximum of 1,438.4
feet above sea level in 1867 and a minimum of 1,400.9 feet above sea level in
1940 (fig. 2). On May 25, 1995, the lake level was 1,435.1 feet above sea
level. This lake level is about 12.5 feet higher than the level recorded in
February 1993 and the highest level in about 120 years.
Figure 2. Historic water level for Devils Lake, 1867-1995. (Postscript Version)
The estimated mean annual inflow to Devils Lake for 1950-93 is 65,500 acre-feet. The estimated annual inflow for 1993 is 296,000 acre-feet, the estimated annual inflow for 1994 is 216,000 acre-feet, and the estimated inflow for January 1 through May 31, 1995, is 292,000 acre-feet. Total inflow to Devils Lake for 1993-95 accounts for about 24 percent of all inflow to Devils Lake for 1950 through May 31, 1995.
Seasonal precipitation, evaporation, and inflow data for Devils Lake were estimated and compiled for 1950-93 (Wiche and Vecchia, 1995). The data were used to generate 2,000 possible future sequences of precipitation, evaporation, and inflow. These values then were used to generate 2,000 possible future lake-level traces, each 50 years in length. The model closely reproduced the statistics of recorded seasonal precipitation, evaporation, and inflow and recorded lake-level data for 1950-93 for Devils Lake. The chance that a given lake level will be exceeded can be determined by evaluating the 2,000 possible maximum lake levels in each year (table 1). The chance of a given lake level occurring is dependent on the previous precipitation, evaporation, and inflow and on the starting lake level. The starting lake level for the spring of 1995, when the lake level was 1,435.0 feet above sea level, was used for the simulations shown in table 1. Chances are 1 in 10 that the lake level will exceed 1,438.1 feet above sea level in 1996 and 1 in 100 that the lake level will exceed 1,443.0 feet above sea level in 1996 (table 1).
Table 1. Possible future levels of Devils Lake given
the initial conditions that existed in the
spring of 1995 (starting lake level is
1,435.0 feet)
--------------------------------------------------
Year 1 in 100 1 in 50 1 in 20 1 in 10 1 in 2
--------------------------------------------------
1995 1,437.8 1,437.3 1,436.6 1,436.0 1,435.0
1996 1,443.0 1,441.9 1,439.6 1,438.1 1,435.3
1997 1,445.3 1,443.3 1,440.5 1,438.8 1,435.2
1998 1,446.2 1,444.3 1,441.1 1,439.1 1,434.8
1999 1,446.3 1,444.2 1,441.4 1,439.1 1,434.4
2000 1,446.6 1,444.4 1,441.4 1,439.1 1,434.1
2001 1,446.3 1,444.6 1,441.2 1,439.2 1,433.8
2002 1,446.5 1,444.7 1,441.4 1,439.1 1,433.5
2003 1,446.5 1,444.4 1,441.3 1,438.9 1,433.2
2004 1,446.0 1,444.2 1,441.2 1,439.0 1,432.9
--------------------------------------------------
The assumed initial lake level, of course, affects the estimated chances of
future lake levels. Possible future lake levels were estimated in 1994 using
the initial lake level for the spring of 1994, when the lake level was 1,430.6
feet above sea level. The resulting lake-level chances are shown in table 2.
On the basis of hydrologic conditions as of June 1, 1994, chances were 1 in 20
that the lake level would exceed 1,436.0 feet above sea level in 1996 and 1 in
100 that the lake level would exceed 1,440.7 feet above sea level in 1996.
However, after initial conditions were changed to those existing in the spring
of 1995, when the lake level was 1,435.0 feet above sea level, chances were 1
in 20 that the lake level would exceed 1,439.6 feet above sea level in 1996 and
1 in 100 that the lake level would exceed 1,443.0 feet above sea level in 1996.
Periodically updating the model to reflect the most recent hydrologic
conditions for Devils Lake allows water-resource managers to base decisions on
the most up-to-date hydrologic information.
Table 2. Possible future levels of Devils Lake given
the initial conditions that existed in the
spring of 1994 (starting lake level is
1,430.6 feet)
--------------------------------------------------
Year 1 in 100 1 in 50 1 in 20 1 in 10 1 in 2
--------------------------------------------------
1994 1,432.9 1,432.4 1,431.8 1,431.3 1,430.6
1995 1,438.4 1,436.9 1,434.6 1,433.3 1,430.8
1996 1,440.7 1,438.5 1,436.0 1,434.2 1,430.7
1997 1,441.9 1,439.5 1,437.1 1,434.7 1,430.3
1998 1,442.6 1,440.2 1,437.5 1,435.0 1,430.0
1999 1,442.8 1,441.0 1,437.5 1,435.4 1,429.8
2000 1,443.1 1,441.4 1,437.7 1,435.7 1,429.7
2001 1,443.0 1,441.8 1,437.8 1,435.7 1,429.5
2002 1,443.0 1,441.5 1,438.1 1,435.7 1,429.3
2003 1,443.1 1,441.2 1,438.4 1,435.9 1,429.1
2004 1,443.4 1,441.7 1,438.8 1,435.7 1,429.0
--------------------------------------------------
Retrieve an Updated Table of Possible future levels of Devils Lake
Aronow, Saul, 1957, On the postglacial history of the Devils Lake
region, North Dakota: Journal of Geology, v. 65, no. 4, p. 410-427.
Upham, Warren, 1895, The glacial Lake Agassiz: U.S. Geological Survey
Monograph No. 25, 658 p.
Wiche, G.J., and Vecchia, A.V., 1995, Lake-level frequency analysis for
Devils Lake, North Dakota: U.S. Geological Survey Open-File Report
95-123, 65 p.
from U.S. Department of the Interior, U.S. Geological Survey, Fact Sheet FS-158-95
District Chief
821 E. Interstate Ave.
Bismarck, ND 58501-1199
Telephone: (701) 250-7400
Fax: (701) 250-7492
Office hours: 8:00 a.m. to 4:30 p.m. Central Time
And try our North Dakota
"Home Page"
on the World Wide Web at
"http://nd.water.usgs.gov/".
|
U.S. Department of the Interior ||
U.S. Geological Survey Maintainer: Webmaster Last update: Tuesday, 24-Aug-2004 12:28:23 EDT Privacy || Disclaimer|| Accessibility || FOIA URL: http://nd.water.usgs.gov/pubs/fs/fs15895/index.html |