Cooper (Chapman) Lake: 76.0% full as of 2024-11-20

The elevation-storage rating curve used to produce the storage hydrograph is made of two segments: (1) the segment up to the conservation pool top (below the red line) is based on measured data, and (2) the segment in the flood pool (above the red line) is an extrapolation from the first segment and shouldn't be relied upon for flood storage information.

Historical Data

Date Percent Full Mean Water Level
(ft) 		Reservoir Storage
(acre-ft) 		Conservation Storage
(acre-ft) 		Conservation Capacity
(acre-ft) 		Surface Area
(acres)
Most recent 2024-11-20 76.0 436.34 232,478 196,703 258,723 15,893
1 day prior 2024-11-19 76.2 436.36 232,796 197,021 258,723 15,904
2 days prior 2024-11-18 76.2 436.37 232,955 197,180 258,723 15,910
1 week prior 2024-11-13 77.0 436.49 234,868 199,093 258,723 15,979
1 month prior 2024-10-20 79.6 436.91 241,630 205,855 258,723 16,220
3 months prior 2024-08-20 93.1 438.99 276,613 240,838 258,723 17,417
6 months prior 2024-05-20 100.0 440.66 306,502 258,723 258,723 18,381
1 year prior 2023-11-20 89.7 438.49 267,977 232,202 258,723 17,129
*

Percent Full is based on Conservation Storage and Conservation Capacity and doesn't account for storage in flood pool.

**

   Values above, including today's are averaged conditions. For near real-time instantaneous water level, see table below or the interactive map viewer.

Most Recent Instantaneous Water Level

Date/time Water Level
(ft) 		Conservation Pool Elevation
(ft) 		Height Above Conservation Pool
(ft)
Most recent 2024-11-20 23:00 436.31 440.00 -3.69 below flood pool
1 hour prior 2024-11-20 22:00 436.31 440.00 -3.69 below flood pool
2 hours prior 2024-11-20 21:00 436.32 440.00 -3.68 below flood pool
6 hours prior 2024-11-20 17:00 436.31 440.00 -3.69 below flood pool
12 hours prior 2024-11-20 11:00 436.34 440.00 -3.66 below flood pool
24 hours prior 2024-11-19 23:00 436.34 440.00 -3.66 below flood pool
48 hours prior 2024-11-18 23:00 436.38 440.00 -3.62 below flood pool
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1991-01-01
Vertical datum NGVD29
Dead pool elevation 415.50 ft above NGVD29
Emergency spillway crest elevation 446.20 ft above NGVD29
Flood pool elevation 446.20 ft above NGVD29
Maximum design elevation 459.50 ft above NGVD29
Top of dam elevation 464.50 ft above NGVD29
Conservation pool elevation 440.00 ft above NGVD29
Data download (CSV) period of record, last one year, last 30 days

Elevation-Area-Capacity Curves

1991-01-01 (source: USGS)
2007-07-01 (source: TWDB) : GIS Data
2022-07-01 (source: TWDB) : GIS Data
Data Source USGS:07342495

Lake Location