Reservoir · Texas · United States · TWDB
Cooper (Chapman) Lake
67.3% full
Capacity
319.13 hm³
Volume stored
215 hm³
Vs month average
86% of normal
Coordinates
33.333°N, 95.625°W
Last updated
2026-10-13
Current fill
67.3%vs 7 days ago
-1.4%losing
vs 1 year ago
-14.4%year-over-year
7-day trend
→stable
Drought context
Storage vs October average
86%of normal
67.3% full on 2026-10-13, against an average of 78.5% for October across 5 years of readings (-11.2 points).
Data source: Texas Water Development Board (Water Data for Texas) — daily reservoir storage volume. Design capacity is unavailable for this site, so fill % is estimated against the 5-year maximum storage and may overstate fullness. Last reading: 2026-10-13.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
About Cooper (Chapman) Lake
As of October 13, 2026, Cooper (Chapman) Lake is filled to 67.3% of its total capacity, holding roughly 215 hm³ of water out of a maximum 319 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (-1.4 pts), and it is 14.4 points below its level on the same date a year earlier.
Across the readings we hold for Cooper (Chapman) Lake — 1446 data points between October 15, 2022 and October 13, 2026 — the level has ranged from a low of 62.6% (October 23, 2022) to a high of 100.0% (February 8, 2023). On average the reservoir is fullest around June and at its lowest around November.
It is operated by TWDB primarily for multiple purposes. It lies within the Texas basin at 33.333°N, 95.625°W.
Key facts
- Current fill level
- 67.3%
- Water stored
- 215 hm³
- Total capacity
- 319 hm³
- 7-day change
- ▼ 1.4 pts
- Year-on-year
- ▼ 14.4 pts
- Primary use
- Multipurpose
- River basin
- Texas
- Operator
- TWDB
- Coordinates
- 33.333°N, 95.625°W
- Last updated
- October 13, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 13 Oct 2026 | 67.3% | 215 |
| 12 Oct 2026 | 67.5% | 215 |
| 11 Oct 2026 | 67.7% | 216 |
| 10 Oct 2026 | 67.9% | 217 |
| 9 Oct 2026 | 68.1% | 217 |
| 8 Oct 2026 | 68.3% | 218 |
| 7 Oct 2026 | 68.5% | 219 |
| 6 Oct 2026 | 68.7% | 219 |
| 5 Oct 2026 | 68.9% | 220 |
| 4 Oct 2026 | 69.1% | 220 |
| 3 Oct 2026 | 68.8% | 220 |
| 2 Oct 2026 | 68.7% | 219 |