Lake Francis Case Water Level
Lake Francis Case is at 1,339.96 ft today (Oct 31), 25.04 ft below its 1,365 ft full pool, down 4.01 ft this week.
South Dakota · Missouri River
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Water level history
About Lake Francis Case
Lake Francis Case is a reservoir on the Missouri River in South Dakota, operated by U.S. Army Corps of Engineers. Its full summer pool sits at 1365 ft above sea level. Live water levels come from the U.S. Army Corps of Engineers (CWMS) and update hourly.
Understanding Lake Francis Case's water level
Lake Francis Case is the Missouri River reservoir that is drained on purpose every fall. Several weeks before the navigation season ends on December 1, the Corps cuts releases from Oahe and Big Bend dams upstream and leaves Fort Randall Dam to carry the river below, so the lake falls to near 1337.5 feet. Through the winter Oahe and Big Bend run their turbines hard to meet heating season power demand, and that water refills Francis Case while Fort Randall itself releases only about 15,000 cubic feet per second, a limit set by the ice covered channel below Gavins Point. No other reservoir in the mainstem system works this way. Before 1971 the drawdown went much deeper, taking as much as two million acre-feet out of the lake. Mudflats in the upper reservoir fed dust storms near Chamberlain and boat ramps were left high and dry, and after studies in 1971 and 1972 the Corps settled on 1337.5 feet as the usual floor. Even that leaves roughly 800,000 acre-feet of empty space below elevation 1350.
By early March the lake is normally back to 1350 feet, the bottom of its annual flood control and multiple use zone. When the plains snowpack between Oahe and Fort Randall is heavy, the Corps holds it lower to leave room for runoff. When flood risk is low it may fill to about 1355 before March 1, and experience has shown that keeping at least 1353 feet from April through September serves recreation and irrigation. The annual zone tops out at 1365 feet, where the lake covers about 94,000 acres. Above that, up to 1375 feet and 102,000 acres, is exclusive flood control space that normally sits empty. It has been used heavily twice. In 1997 the lake entered that zone in late March and stayed there until September 1, and waves tore at the embankment until the Corps held the pool at 1370 feet long enough to add riprap. In July 2011 it peaked at 1374.0 feet, one foot from the top, while Fort Randall released a record 160,000 cubic feet per second.
The reservoir runs 107 river miles from Fort Randall Dam, about six miles south of Lake Andes, up to Big Bend Dam. Its one sizable tributary is the White River, which enters below Chamberlain carrying so much sediment that its delta now stretches across the lake. During the 1991 fall drawdown the Corps noticed the delta acting like a low dam, and the water above it has since stood as much as six feet higher than the main lake. Construction began in August 1946, the river was closed off in July 1952, power generation started in March 1954, and the eighth and final generator came online in January 1956, bringing the plant to 320 megawatts. U.S. Highways 18 and 281 cross on top of the dam. Farther upstream, SD 44 crosses on the Platte Winner Bridge, at 5,655 feet the longest bridge in South Dakota, open since 1966 and now funded for replacement. The lake is named for Francis Higbee Case, a newspaperman who represented South Dakota in Congress for 25 years.
Lake Francis Case — frequently asked
What is Lake Francis Case's full pool?
This site uses 1365 feet, the top of the annual flood control and multiple use zone in the Corps master manual, where the lake covers about 94,000 acres. Day to day it usually sits lower: the Corps aims for about 1350 to 1355 feet in spring and summer and draws it down to near 1337.5 in late fall. Above 1365 is exclusive flood control space up to 1375 feet, which the Corps treats as the maximum operating pool.
Why does Lake Francis Case drop so much every fall?
The drop is deliberate. Before the navigation season ends, Oahe and Big Bend cut their releases and Fort Randall supplies the river below, pulling the lake down nearly 20 feet to roughly 1335 to 1339 feet. That empty space lets the upstream dams generate more power in winter, when ice on the river below Gavins Point limits how much water can be passed downstream. The drawdown is timed late to fall when recreation use drops off.
When does Lake Francis Case refill?
It refills over the winter, roughly December through April, as Oahe and Big Bend send down water for winter power generation. The normal target is 1350 feet by March 1. In years with heavy plains snow the Corps keeps it lower to catch spring runoff, and in dry years it may let it reach about 1355. State biologists note that the rising winter water makes access difficult for ice anglers.
What is the record high on Lake Francis Case?
1374.0 feet in July 2011, one foot below the top of the exclusive flood control zone and nine feet above 1365. That was the highest runoff year on record for the upper Missouri basin, and Fort Randall released a record 160,000 cubic feet per second. Before then, 1997 was the first year the exclusive flood zone was used heavily, and the pool was held at 1370 feet while crews added riprap to the dam.
How low can Lake Francis Case go?
In a normal year the fall drawdown bottoms out near 1337.5 feet, and state biologists report it typically reaching about 1335 to 1339. That limit dates from the early 1970s; before then the lake was pulled much lower each fall. The Corps manual allows a drawdown to 1320 feet, the top of the permanent pool, only during a drought worse than the 1930s. The lake first reached 1320 while filling on 24 November 1953.
Which Lake Francis Case boat ramps work at low water?
In Game, Fish and Parks' 2017 management plan, the deepest ramp ends were North Bay at 1326 feet, St. Francis Bay at 1333, Snake Creek at 1334, South Wheeler at 1336, and Whetstone and American Creek Marina at 1337. Several others, including South Shore, White Swan, Joe Day Bay and Buryanek, end at 1348, so they are out of the water during the fall drawdown. Siltation has also made the Boyer ramp unusable.
What is the fishing like on Lake Francis Case?
Walleye are the main draw, according to South Dakota Game, Fish and Parks. The lake supported between about 85,000 and 151,000 angler days a year from 2005 to 2015. Biologists say the fall drawdown dries out shallow habitat and pushes fish out of the shoreline zone. Since 2012 the lake has also hosted one of the state's two paddlefish snagging seasons, built on decades of stocking.
Other lakes near Lake Francis Case
See current levels for all 6 South Dakota lakes and reservoirs →
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