Chatfield Reservoir

Chatfield Reservoir, which many locals call Chatfield Lake, is the reservoir at the heart of Chatfield State Park in Littleton, on Denver's southwest edge. The U.S. Army Corps of Engineers built the dam after the June 1965 South Platte flood, starting in 1967 and finishing in 1975, and the water now draws boaters, water skiers, paddlers, swimmers and anglers. Boating runs from March 1 (ice permitting) through November 30, swimming is allowed only at the swim beach, and anglers fish open water in spring and summer and through the ice in winter.

Where the Water Comes From

The reservoir sits where the South Platte River flows out of the mountains onto the prairie at the mouth of Waterton Canyon, and where Plum Creek joins it. The park lies in the lower foothills of the Front Range, a gently rolling plain at about 5,450 feet. The less developed, wilder side of the park is to the south, along Plum Creek and the Platte.

Why the Reservoir Exists

Chatfield was built for floods, not recreation. Colorado Parks and Wildlife's history notes that the June 1965 flood on Plum Creek and the South Platte was catastrophic. In response the Army Corps of Engineers began the Chatfield Dam and Reservoir in 1967 and finished in 1975, the year the state park opened. Colorado State Parks took on a long-term lease to manage the recreation area in 1974.

How the Lake Is Laid Out for Boats

The main body of the reservoir is the power zone, for general boating and water skiing, and traffic moves counter-clockwise. Two large no-wake zones sit at the southwest and southeast ends. On busy summer days the reservoir can reach boating capacity; when it does, rangers at the ramps hold new launches until a boat comes off the water. Ramps, inspections and launch hours are on the Boating page.

Can You Swim in Chatfield Reservoir?

Only at the swim beach, from Memorial Day through Labor Day. The park brochure says swimming is not allowed at the marina, the boat docks, anywhere marked with Keep Out signs or buoys, or more than 75 feet from shore in the power zone, and no one may swim from sunset to sunrise. There is no lifeguard.

Cold Water and Weather

CPW classes most Colorado water as "cold water," under 70 degrees, for most of the year. Cold water shock can make even a strong swimmer gasp and inhale water. Afternoon storms on the Front Range usually build from the west and arrive fast, and wind is the main reason paddlers end up in the water. Wear a life jacket and head in early when clouds stack up over the foothills.

Winter on the Reservoir

From December 1 until the ice goes off, and through at least March 1, the reservoir is closed to all boats and paddle craft. Ice fishing takes over, usually by mid-December. Ice rescue stations, red poles with a tire and rope, stand around the shoreline (Fishing).

Current Closures

CPW reports ongoing tree-removal work around the reservoir with multiple closures in place, tied to the Chatfield Reservoir reallocation and mitigation project. Obey every closure sign; check CPW's park page for the latest before you go.

Wildlife on the Water

American white pelicans and mallards are among the birds CPW lists at Chatfield, and the Heronry Overlook looks out over great blue heron nesting trees south of the reservoir (About the Park). New Zealand mudsnails, an invasive species, have been found in the reservoir, so clean, drain and dry boats and gear before you leave.