Cooper (Chapman) Lake: 68.2% full as of 2026-10-09
Historical Data
| Date | Percent Full |
Mean Water Level (ft) |
Reservoir Storage (acre-ft) |
Conservation Storage (acre-ft) |
Conservation Capacity (acre-ft) |
Surface Area (acres) |
|
|---|---|---|---|---|---|---|---|
| Today | 2026-10-09 | 68.2 | 435.03 | 212,254 | 176,479 | 258,723 | 14,963 |
| Yesterday | 2026-10-08 | 68.3 | 435.05 | 212,554 | 176,779 | 258,723 | 14,978 |
| 2 days ago | 2026-10-07 | 68.5 | 435.08 | 213,003 | 177,228 | 258,723 | 15,001 |
| 1 week ago | 2026-10-02 | 68.7 | 435.12 | 213,604 | 177,829 | 258,723 | 15,033 |
| 1 month ago | 2026-09-09 | 73.4 | 435.91 | 225,706 | 189,931 | 258,723 | 15,601 |
| 3 months ago | 2026-07-09 | 88.2 | 438.25 | 263,882 | 228,107 | 258,723 | 16,991 |
| 6 months ago | 2026-04-09 | 79.4 | 436.89 | 241,306 | 205,531 | 258,723 | 16,209 |
| 1 year ago | 2025-10-09 | 82.6 | 437.39 | 249,482 | 213,707 | 258,723 | 16,497 |
*
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 | 2026-10-09 05:00 | 435.02 | 440.00 | -4.98 |
| 1 hour prior | 2026-10-09 04:00 | 435.02 | 440.00 | -4.98 |
| 2 hours prior | 2026-10-09 03:00 | 435.01 | 440.00 | -4.99 |
| 6 hours prior | 2026-10-08 23:00 | 435.03 | 440.00 | -4.97 |
| 12 hours prior | 2026-10-08 17:00 | 435.04 | 440.00 | -4.96 |
| 24 hours prior | 2026-10-08 05:00 | 435.06 | 440.00 | -4.94 |
| 48 hours prior | 2026-10-07 05:00 | 435.09 | 440.00 | -4.91 |
*
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 |
| USGS Monitoring Location | USGS:07342495 |
Lake Location
