The zoned and compacted earthfill-type dam provides for the retention and regulation of water discharged into Chimney Hollow from Flatiron Power Plant. It consists of an impervious central core flanked by zones of relatively free-draining material grading to pervious at the outer slopes of the dam. The upstream zone is designed to resist percolation of the afterbay water and to dissipate internal pressures exerted outwardly during rapid afterbay drawdowns. The downstream zones protects the impervious central core and stabilizes the dam by lowering the saturation line in the downstream area. The cutoff trench beneath the dam is designed to obstruct percolation along the foundation contact to prevent dangerous seepage velocities. The stability of the dam is further safeguarded by the embankment toe drains which intercept seepage along the foundation contact and surface flow from within the dam. The toe drains are designed to permit easy escape of the seepage and to lower the ground water table sufficiently to avoid the formation of boggy areas below the dam.
General
Project
Colorado-Big Thompson
Longitude
-105.2233
Latitude
40.3683
Reservoir
Flatiron
Original Construction
1951-1953
National ID Number
CO01654
Watercourse
Chimney Hollow Creek
Dimensions
Crest Elevation
5486.0 ft
Structural Height
86.0 ft
Hydraulic Height (Normal Operating Depth at Dam)
55.0 ft
Crest Length
1725.0 ft
Top of Active Conservation Pool (Elevation)
5472.8 ft
Top of Inactive Conservation Pool (Elevation)
5462.0 ft
Spillway Crest Elevation
5472.8 ft
Top of Dead Storage Pool (Elevation)
5454.75 ft
Streambed at Dam Axis
4317.0 ft
Hydraulics & Hydrology
Normal Water Surface Elevation
5472.8 ft
Spillway Capacity at Elevation
23600 cfs at 5480.0 ft
Outlet Works Capacity at Elevation
930 cfs at 5464.8 ft
Drainage Area
7.1 sq mi
Hydrometeorological Report (HMR)
HMR 55A
Contact
Owner
Title: Area Office Manager Organization: Eastern Colorado Area Office Address: 11056 W. County Rd 18E City: Loveland, CO 80537-9711 Fax: 970-663-3212 Phone: 970-461-5410
Operator
Title: Area Office Manager Organization: Eastern Colorado Area Office Address: 11056 W. County Rd 18E City: Loveland, CO 80537-9711 Fax: 970-663-3212 Phone: 970-461-5410
More Information about the U.S. Bureau of Reclamation