High water levels of the chain of lakes tributary to Devils Lake, North Dakota have, in recent years, caused flooding of cropland and county roads, thus disrupting agricultural interests. High water levels of Devils Lake pose a flood threat to the city of Devils Lake, Camp Grafton National Guard Camp, and road, sewer, and lagoon systems of several communities. The chain of lakes acts as an evaporation and storage basin. During the spring and summer of 1985, about 25,980 acre-feet of runoff flowed into the chain of lakes from upstream tributaries. About 10,180 acre-feet (about 39 percent) of that runoff flowed out of the chain of lakes. By September 30, 1985, about 440 acre-feet (less than 2 percent of the runoff that flowed into the chain of lakes) remained in storage in the chain of lakes upstream of Devils Lake. The other 15,360 acre-feet (about 59 percent of the runoff that flowed into the chain of lakes) was removed from the chain of lakes, mainly by evaporation.

High-runoff conditions for Devils Lake were simulated on the basis of records of hydrologic and climatologic data for the years 1985-2032, and a low-runoff condition for Devils Lake was simulated for the years 1985-1990. The January 1985 water level of 1,426.12 feet above sea level was used for the initial lake level. A combination of storage conditions in the upstream chain of lakes and different hydrologic and climatologic variables were used for the high-runoff-condition simulations. For existing storage conditions in the chain of lakes, Devils Lake would have a maximum water level ranging from 1,432.0 to 1,442.6 feet above sea level. For midlevel storage conditions, maximum water levels of Devils Lake would range from 1,432.4 to 1,441.4 feet above sea level. For highlevel storage conditions, maximum water levels of Devils Lake would range from 1,431.3 to 1,439.9 feet above sea level. The low-runoff condition simulation indicates that Devils Lake would have a minimum water level of 1,420.7 feet above sea level.