Standley Lake Dam

Upon completion, Standley Lake’s earthen dam was reported to be the largest of its kind in the United States, and possibly the second largest in the world. Three million cubic yards of soil had been excavated and moved to create a dam wall measuring 700-feet wide at the base, 1.25 miles long and 113-feet high. The lake was filled with water from Clear Creek, Coal Creek, Ralston Creek and Leyden Creek, delivered by way of the Croke (formerly Kinnear) Canal and Church Ditch. Water also entered the lake from the upper reaches of Big Dry Creek and Woman Creek above the reservoir. Additional water was secured from the Farmers High Line Canal. The twin outflow from Standley Lake divided the water below the dam between the Niver Canal and Big Dry Creek.

In 2003/2004, the spillway was constructed. Currently, the reservoir covers approximately 1,100 surface acres, with adjoining land covering an additional 2,000 acres. 42,000 acre-feet of water can be stored when full, with a maximum depth of 96 feet at the dam face. Ninety-six percent of the water comes from Clear Creek via an irrigation ditch. The remaining percent comes from Woman’s Creek and adjacent drainages. The water from Standley Lake Reservoir is used as a municipal water supply for the Cities of Westminster, Northglenn and Thornton. It is also used for agricultural irrigation, recreation and wildlife habitat.