Cooper (Chapman) Lake: 87.7% full as of 2021-10-22

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 2021-10-22 87.7 438.13 267,009 228,411 260,332 16,514
1 day prior 2021-10-21 87.9 438.16 267,505 228,907 260,332 16,527
2 days prior 2021-10-20 88.1 438.19 268,001 229,403 260,332 16,541
1 week prior 2021-10-15 89.2 438.36 270,819 232,221 260,332 16,621
1 month prior 2021-09-22 91.9 438.78 277,845 239,247 260,332 16,843
3 months prior 2021-07-22 100.0 440.12 301,070 260,332 260,332 - n.a. -
6 months prior 2021-04-22 100.0 440.23 303,044 260,332 260,332 - n.a. -
1 year prior 2020-10-22 77.3 436.45 239,845 201,247 260,332 15,846
*

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 2021-10-25 11:00 438.04 440.00 -1.96 below flood pool
1 hour prior 2021-10-25 10:00 438.04 440.00 -1.96 below flood pool
2 hours prior 2021-10-25 09:00 438.03 440.00 -1.97 below flood pool
6 hours prior 2021-10-25 05:00 438.04 440.00 -1.96 below flood pool
12 hours prior 2021-10-24 23:00 438.06 440.00 -1.94 below flood pool
24 hours prior 2021-10-24 11:00 438.07 440.00 -1.93 below flood pool
48 hours prior 2021-10-23 11:00 438.10 440.00 -1.90 below flood pool
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1991-01-01
Vertical datum NGVD29
Gauge USGS:07342495
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

Lake Location