Reservoir · Oklahoma · United States · USACE CWMS
Foss Lake
90.4% full
Capacity
208.13 hm³
Volume stored
188 hm³
Coordinates
35.538°N, 99.178°W
Last updated
2026-07-30
Current fill
90.4%vs 7 days ago
0.0%stable
vs 1 year ago
-4.1%year-over-year
7-day trend
→stable
Data source: USACE CWMS — US Army Corps of Engineers — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-07-30.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 35.538, -99.178 · Open in Google Maps
About Foss Lake
As of July 30, 2026, Foss Lake is filled to 90.4% of its total capacity, holding roughly 188 hm³ of water out of a maximum 208 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it is 4.1 points below its level on the same date a year earlier.
Across the readings we hold for Foss Lake — 329 data points between July 31, 2021 and July 30, 2026 — the level has ranged from a low of 86.7% (January 26, 2022) to a high of 96.7% (April 15, 2026). On average the reservoir is fullest around April and at its lowest around February.
It is operated by USACE primarily for multiple purposes. It lies within the Oklahoma basin at 35.538°N, 99.178°W.
Key facts
- Current fill level
- 90.4%
- Water stored
- 188 hm³
- Total capacity
- 208 hm³
- 7-day change
- No change
- Year-on-year
- ▼ 4.1 pts
- Primary use
- Multipurpose
- River basin
- Oklahoma
- Operator
- USACE
- Coordinates
- 35.538°N, 99.178°W
- Last updated
- July 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Jul 2026 | 90.4% | 188 |
| 29 Jul 2026 | 90.4% | 188 |
| 28 Jul 2026 | 90.6% | 188 |
| 27 Jul 2026 | 90.6% | 189 |
| 26 Jul 2026 | 90.8% | 189 |
| 25 Jul 2026 | 90.9% | 189 |
| 24 Jul 2026 | 91.0% | 189 |
| 23 Jul 2026 | 91.1% | 190 |
| 22 Jul 2026 | 91.3% | 190 |
| 21 Jul 2026 | 91.4% | 190 |
| 20 Jul 2026 | 91.4% | 190 |
| 19 Jul 2026 | 91.6% | 191 |
Frequently asked questions
What is the current water level of Foss Lake?
As of July 30, 2026, Foss Lake is at 90.4% of its capacity, holding approximately 188 hm³ of water, according to USACE CWMS (US Army Corps of Engineers) data.
Is Foss Lake reservoir full?
No. As of July 30, 2026, Foss Lake is high at 90.4% of its capacity, so it is not full.
Is the water level at Foss Lake rising or falling?
The level at Foss Lake has been broadly stable over the latest week on record (0.0 points).
How much water can Foss Lake hold?
Foss Lake has a total capacity of 208 hm³.
Where is Foss Lake reservoir located?
Foss Lake is located in Oklahoma, United States, within the Oklahoma basin (coordinates 35.538°N, 99.178°W).
What is Foss Lake used for?
Foss Lake is used primarily for multiple purposes, and is managed by USACE.