Lake Mendota at Madison water level — Wisconsin
Lake Mendota at Madison in Wisconsin was last measured at 849.96 ft (datum NGVD29), as of Aug 31, 2026, 3:00 AM (UTC-05:00) (USGS Water Services). Over its recent trend window the level has been rising (+0.1 ft). This reading is provisional and subject to revision.
- % of conservation pool full
- Not reported
- Storage
- Not reported
- Recent trend
- ↑Rising
+0.1 ft over the trend window
Recent trend
Readings this station published between Jun 2, 2026 and Aug 31, 2026 — a 89-day window — downsampled for display.
Data: USGS Water Services (waterservices.usgs.gov) and USACE CWMS Data (cwms-data.usace.army.mil), retrieved 2026-08-31. Both public domain (a work of the U.S. Government, 17 U.S.C. §105).
Source: USGS site 05428000, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for this lake →
About this gauge's record
This site's drainage basin covers approximately 233 sq mi of contributing watershed.
The dam behind Lake Mendota at Madison
Lake Mendota at Madison is held back by Mendota Locks (also recorded as Tenney Park Locks) , a other structure , standing 16 ft high and running 100 ft along its crest , built across YAHARA RIVER in Dane County , near MADISON . It was completed in 1849 and modified in 1959O , and is owned by Dane County (a local government owner) .
Its recorded primary purpose is navigation — the pool is held inside a narrow band to keep a navigable depth, so large swings are rare by design . It also serves navigation;recreation.
Its spillway is gated, so the operator can hold the pool above the spillway crest and meter what leaves.
NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. That assessment is dated 06/14/2021.
At its normal pool the reservoir covers about 9,730 acres. NID records a maximum storage of 160,000 acre-ft against a normal storage of 132,000 acre-ft. Its maximum discharge capacity is 1,860 cubic feet per second. It is regulated by WIDNR.
Dam facts: National Inventory of Dams record WI00621 , filed by Wisconsin — U.S. Army Corps of Engineers, public domain. Water levels above come from USGS Water Services and are a separate source. (How this dam was matched to this gauge →)
How Lake Mendota at Madison compares nearby
3 of 6 nearby lakes with a current trend are also rising right now.
Nearby lakes
The six nearest published lakes by centroid distance (great-circle) — cross-state neighbors included.
| Lake | State | Level | Distance |
|---|---|---|---|
| Lake Monona at Madison | WI | 845.03 ft | 4 km |
| Lake Waubesa at Mc Farland | WI | 844.78 ft | 11 km |
| Lake Kegonsa at Barber Drive | WI | 843.29 ft | 17 km |
| Lake Koshkonong | WI | 776.57 ft | 44 km |
| North Lake | WI | 907.09 ft | 72 km |
| Geneva Lake at Lake Geneva | WI | 864.35 ft | 95 km |
Frequently asked questions
- What is the current water level of Lake Mendota at Madison?
- As of Aug 31, 2026, 3:00 AM (UTC-05:00), the pool elevation was 849.96 ft (datum NGVD29), provisional and subject to revision. See the trend chart above for the recent direction.
- Is Lake Mendota at Madison full right now?
- Its managing agency does not publish a %-of-conservation-pool-full figure for this lake, so we show the bare level rather than estimate one.
- Where does this data come from?
- From USGS site 05428000, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00).
More in Wisconsin
See every lake tracked in Wisconsin, or read the methodology behind these figures.