Eden Dam is a series of irregular dikes originally built under the Carey Act by Eden Irrigation and Land Company about 1907. In 1959, the Bureau of Reclamation constructed a new outlet works from the reservoir through the abutment in the southeast side of the reservoir to supply the old Eden Canal.
The reservoir is approximately 2.5 miles at its widest point, and 2 miles in length with a surface area of about 1,100 acres.The outlet works consists of a concrete lined tunnel controlled by constant head orifice gates and an overflow control structure.
The spillway is contained in the outlet works as an uncontrolled concrete overflow structure above the orifice gates. The spillway has a crest width of 15 feet and crest elevation of 6713.5 feet. A 22 inch wood beam has been added to the top of the spillway to get a new crest elevation of 6715.2 feet. The spillway is used only in an emergency since the water inflow to the reservoir is controlled by diversions through the Little Sandy Feeder Canal.