Big Sandy Lake Water Level
Big Sandy Lake is at 1,216.02 ft today (Oct 31), 0.54 ft below its 1,216.56 ft full pool, up 0.03 ft this week.
Minnesota · Sandy River
Get a text when Big Sandy Lake crosses a level you pick →
Sponsor Big Sandy Lake
Put your marina, real-estate, or local business in front of everyone checking this lake's level. One exclusive sponsor per lake.
Renews automatically each month or year until you cancel. Cancel anytime online. Terms · Manage or cancel · Questions?
Water level history
About Big Sandy Lake
Big Sandy Lake is a reservoir on the Sandy River in Minnesota, operated by U.S. Army Corps of Engineers. Its full summer pool sits at 1216.56 ft above sea level. Live water levels come from the U.S. Army Corps of Engineers (CWMS) and update hourly.
Understanding Big Sandy Lake's water level
Big Sandy Lake is the reservoir behind the Sandy Lake Dam at Libby, about nine miles north of McGregor in Aitkin County. The dam sits on the Sandy River, which leaves the lake at its northwest corner and joins the Mississippi a short distance west. The Prairie River comes in from the east through Bill Horn Bay, and the Sandy enters from the south. The St. Paul District of the Corps of Engineers began storing water here in 1893, finished a timber crib dam in 1895, and replaced it with the present concrete structure in 1911. It is one of six Mississippi River headwaters reservoirs, and it was the only one built with a lock. The 160 by 30 foot chamber no longer passes boats, and the 1914 lock house has served as the Corps visitor center since the 1970s. Gates, lock bulkhead wall, and the old timber apron were rebuilt in concrete and steel during a $5.3 million rehabilitation from 2021 to 2023.
The level follows a yearly cycle written into the Corps operating plan. The top of the normal summer band is 1,216.56 feet (NGVD 1929), the full pool figure shown on this page, and the band is centered near 1,216.3. Drawdown starts in the fall, usually around October 1, and normally takes the lake down 2 feet to 1,214.31, the lowest level allowed under Congressional legislation, by the end of February. Late winter snow surveys decide how deep the drawdown actually goes, and when snowpack is heavy the Corps holds the lake at 1,214.31 until melt begins. Melt can refill it fast. In 2023 the pool bottomed at 1,214.12 on April 8 and stood at 1,220.77 on April 29. Above 1,216.56 the lake is in flood storage, which runs to 1,218.31; the top of the dam is 1,221.31.
The worst floods come when the Mississippi itself is high. Big Sandy normally drains into the river, but when the river rises the outlet backs up and the lake climbs with it. After about seven inches of rain in June 2012 the pool peaked at 1,222.93 feet late on June 28, roughly 6.4 feet above the summer band. Docks ended up hundreds of feet offshore and dozens of homes flooded. The flood also killed off most of the lake's tullibee, which dropped to 0.12 per gill net in 2013 before rebounding, and it let channel catfish move past the dam from the river. The DNR manages the lake first for walleye, with black crappie and northern pike as secondary species. Its tea colored water, stained by tannins from the Sandy and Prairie river wetlands, averages about 4.5 feet of clarity, and 47 percent of its 6,526 acres is under 15 feet deep.
Big Sandy Lake — frequently asked
What is Big Sandy Lake's full pool elevation?
The Corps lists 1,216.56 feet (NGVD 1929) as the top of the normal summer band, and that is the full pool figure used here. The bottom of the normal range is 1,214.31 feet, the winter drawdown target. Water above 1,216.56 is held as flood storage up to 1,218.31 feet, and the dam structure tops out at 1,221.31. Readings near 1,216 feet in late summer and early fall are normal.
When does the Corps draw down Big Sandy Lake?
Drawdown usually begins in early October. The normal target is 1,214.31 feet, 2 feet below the middle of the summer band and the lowest level allowed under Congressional legislation, and it is typically reached by the end of February. Snow surveys in late February and early March set the final level. In a heavy snow year the Corps holds the lake at full drawdown until melt starts, to leave room for the runoff.
What is the record high level on Big Sandy Lake?
The USGS record high is 1,224.82 feet on May 19, 1950, more than 8 feet above the summer band. The highest pool in recent decades was 1,222.93 feet late on June 28, 2012, after heavy June rain. That crest flooded dozens of homes around the lake and left resort docks hundreds of feet offshore. Spring peaks above 1,221 feet also came in 1969, 1975, 1979, and 2001. The recent high and low shown in the gauge panel above come only from the last few years of Corps readings, so they sit well inside these historic marks.
What is the lowest Big Sandy Lake has been?
The USGS record low is 1,207.96 feet on January 20, 1921, more than 8 feet below today's summer band and about 6 feet under the modern winter drawdown target. Readings in the 1,208 foot range were common in the dam's early decades. Since the current operating plan took hold, winter lows have generally stayed close to the 1,214.31 foot drawdown floor, apart from a few years such as 1975, when the pool fell to 1,212.74 in April.
Why does Big Sandy Lake flood when the Mississippi is high?
The lake drains through the Sandy River into the Mississippi just west of the dam. When the Mississippi is swollen, the lake cannot empty, so it rises with the river no matter how the gates are set. In 2012 and again in spring 2022 the river and the lake stood at nearly the same elevation. DNR biologists think that is how channel catfish crossed the dam and became established in the lake.
What happened at Sandy Lake in 1850?
In 1850 federal officials moved the Lake Superior Ojibwe's annuity payment from La Pointe, Wisconsin, to Sandy Lake and then held it until the waterways froze, hoping to keep the bands in Minnesota Territory. Thousands waited through November and December with little food. About 400 died: roughly 150 at the lake from measles, dysentery, and hunger, and more on the walk home. The Mikwendaagoziwag memorial stands at the Corps recreation area on the lake's northwest shore.
How is the walleye fishing on Big Sandy Lake?
Walleye are the DNR's primary management species. The 2022 survey caught 5.7 per gill net, just under the lake's long term average of 6.6, with fish averaging 11.5 inches. A 14 to 18 inch harvest slot that began in 2011 appears to have improved natural reproduction. Crappie and bluegill growth rank among the best in the Aitkin area, and the Corps and DNR have tagged walleye to learn whether fish leave the lake past the dam.
Other lakes near Big Sandy Lake
See current levels for all 6 Minnesota lakes and reservoirs →
Add this gauge to your website
Run a marina, boat rental, guide service, or real-estate site on Big Sandy Lake? Put this free live-level widget on your page — just copy and paste the code: