Water Supply and Overflows
Devils Lake receives nearly all of its water from surface runoff and direct precipitation. Most surface-water runoff originates from a chain of remnant lakes located a few kilometers north of Devils Lake, although many of these smaller lakes have now merged with Devils Lake as the water levels rise. Total annual inflows ranged from near zero during the drought-stricken 1930s to nearly 400,000 acre-feet in 1993. Inflows, averaging 65,500 acre-feet annually between 1950 and 1993, rose to 317,000 acre-feet annually between 1993 and 2000, a fivefold increase. The years 1993 to 1995 contributed 24 percent of all inflow to Devils Lake between 1950 and 1995.
If Devils Lake rises approximately two additional meters and begins overflowing, as scientists predict it will, lake waters will enter the Sheyenne River. The Sheyenne, which originates 50 kilometers west of the rivers juncture with the Tolna Coulee outlet, meanders on an easterly course that lies about 15 kilometers south of the Devils Lake Basin. After turning south, the river is impounded by a Corps of Engineers dam located 20 kilometers north of Valley City, a town of about 6,300 residents. The dams narrow reservoir extends 43 kilometers upstream and contains about 71,000 acre-feet of water at full capacity. After passing through Valley City, the river joins the Red River of the North near the city of Fargo. The Red River flows northward before emptying into Canadas Lake Winnipeg.
【雅思阅读考前必看—Runaway Devils Lake】相关文章:
最新
2016-02-26
2016-02-26
2016-02-26
2016-02-26
2016-02-26
2016-02-26