Cooper (Chapman) Lake is 95.2% full as of 2016-07-25

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, while 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.

Date Percent Full Mean Water Level
(ft)
Reservoir Storage
(acre-ft)
Conservation Storage
(acre-ft)
Conservation Capacity
(acre-ft)
Surface Area
(acres)
Most recent 2016-07-25 95.2 439.28 286,345 247,747 260,332 17,169
1 day prior 2016-07-24 95.4 439.31 286,860 248,262 260,332 17,191
2 days prior 2016-07-23 95.6 439.34 287,377 248,779 260,332 17,214
1 week prior 2016-07-18 96.3 439.45 289,275 250,677 260,332 17,301
1 month prior 2016-06-25 100.0 440.07 300,177 260,332 260,332 - n.a. -
3 months prior 2016-04-25 100.0 441.55 327,573 260,332 260,332 - n.a. -
6 months prior 2016-01-25 100.0 441.67 329,879 260,332 260,332 - n.a. -
1 year prior 2015-07-25 99.9 439.99 298,752 260,154 260,332 17,935
*

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 2016-07-25 17:00 439.25 440.0 -0.8 below flood pool
1 hour prior 2016-07-25 16:00 439.27 440.0 -0.7 below flood pool
2 hours prior 2016-07-25 15:00 439.27 440.0 -0.7 below flood pool
6 hours prior 2016-07-25 11:00 439.28 440.0 -0.7 below flood pool
12 hours prior 2016-07-25 05:00 439.28 440.0 -0.7 below flood pool
24 hours prior 2016-07-24 17:00 439.31 440.0 -0.7 below flood pool
48 hours prior 2016-07-23 17:00 439.34 440.0 -0.7 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 415.5 ft above NGVD29
Conservation pool elevation 440.0 ft above NGVD29
Emergency spillway crest elevation 446.2 ft above NGVD29
Flood pool elevation 446.2 ft above NGVD29
Maximum design elevation 459.5 ft above NGVD29
Top of dam elevation 464.5 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