R655-11-6B. Dam Crest Requirements

A. The crest width of all dams should be, at a minimum, equal to the structural height of the dam divided by five plus five feet. The absolute minimum required shall be 12 feet and the absolute maximum required shall be 25 feet. Wider crest widths may be used at the designer's discretion.

B. All dams shall have a cross slope on the crest of 2% to 3% towards the reservoir.

C. All crests shall be protected with a wearing surface of granular material to prevent vehicular rutting.

D. Dam crests should be cambered to allow for anticipated settlement. The side slopes of the dam may be steepened to accommodate the camber.

E. For dams over 500 feet long which have a crest that dead ends, a turn-around should be provided at the abutment.

F. The impervious portion of the dam under the crest may need to be terminated at the anticipated frost line to prevent desiccation cracking and damage from frost; however, it needs to be carried high enough to prevent seepage over the core by capillary rise.