Located 1.5 miles south of Wanship on the Weber River, the Wanship Dam impounds Rockport Lake. The lake has 62,100 acre-feet total capacity, and a surface area of 1,080 acres. The dam, a zoned earthfill structure, is 156 feet high, has a crest length of 2,010 feet, and contains 3,183,000 cubic yards of material. The spillway is an uncontrolled open concrete chute with a capacity of 10,800 cubic feet per second. The outlet works tunnel provides for releases to the powerplant or to the river. The outlet works has a capacity of 1,000 cubic feet per second.
Wanship Dam and Rockport Lake are located on the Weber River where it cuts through shale, siltstone and sandstone beds of the Frontier Formation of Late Creracious age. Bedrock is primarily shale and siltstone with sandstone beds that form resistant ridges. Impure coal and bentonite are interbedded with the shale. The dam and reservoir are on the north limb of the Uinta Mountain uplift. The beds dip 25 degrees to 35 degrees downstream. Several northeast trending thrust faults cross the Weber Valley in the vicinity of the dam and reservoir.