Rend Lake Tw water level — Illinois
Rend Lake Tw in Illinois was last measured at 373.65 ft (datum NAVD88), as of Jul 29, 2026, 1:00 PM (UTC+00:00) (USACE CWMS Data). Over its recent trend window the level has been falling (−0.5 ft).
- % of conservation pool full
- Not reported
- Storage
- Not reported
- Recent trend
- ↓Falling
−0.5 ft over the trend window
Recent trend
Readings this station published between Jun 2, 2026 and Jul 29, 2026 — a 57-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: USACE MVS/Rend Lk TW-Big Muddy, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for this lake →
The dam behind Rend Lake Tw
Rend Lake Tw is held back by Rend Dam (also recorded as Rend Lake) , a concrete structure , standing 54 ft high and running 10,228 ft along its crest , built across BIG MUDDY RIVER in Franklin County , near BENTON . It was completed in 1971 , and is owned by USACE - St. Louis District (a federal owner) , to a design credited to CEMVS.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain . It also serves flood risk reduction;other;fish and wildlife pond;recreation;water supply.
It is founded on rock;soil, with a earth core. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. The spillway opening is 1,235 ft wide. Its outlet works use none0.
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.
At its normal pool the reservoir covers about 18,900 acres. NID records a maximum storage of 607,910 acre-ft against a normal storage of 184,675 acre-ft. Its maximum discharge capacity is 87,250 cubic feet per second.
Dam facts: National Inventory of Dams record IL00117 , filed by US Army Corps of Engineers — U.S. Army Corps of Engineers, public domain. Water levels above come from USACE CWMS Data and are a separate source. (How this dam was matched to this gauge →)
How Rend Lake Tw compares nearby
5 of 6 nearby lakes with a current trend are also falling right now.
Nearby lakes
The six nearest published lakes by centroid distance (great-circle) — cross-state neighbors included.
| Lake | State | Level | Distance |
|---|---|---|---|
| Sub | IL | 405.60 ft | 16 km |
| Spring Garden | IL | 417.80 ft | 16 km |
| Plumfield | IL | 355.97 ft | 17 km |
| Sub Casey | IL | 405.58 ft | 17 km |
| Waltonville | IL | 413.04 ft | 25 km |
| Mt Vernon Casey | IL | 421.12 ft | 29 km |
Frequently asked questions
- What is the current water level of Rend Lake Tw?
- As of Jul 29, 2026, 1:00 PM (UTC+00:00), the pool elevation was 373.65 ft (datum NAVD88). See the trend chart above for the recent direction.
- Is Rend Lake Tw 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 USACE MVS/Rend Lk TW-Big Muddy, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00).
More in Illinois
See every lake tracked in Illinois, or read the methodology behind these figures.