A man-made lake along the lower St. Croix River was unexpectedly and unintentionally drained last weekend when the valve on a control structure was stuck open. Lake Alice at William O’Brien State Park is now almost entirely dry, except for a small stream running through its middle.

The 26-acre lake is essentially a spring-fed river backwater that has been dammed by an earthen dike. DNR staff can use a valve installed in 1960 to control lake depth, which is where the problem began.

Photos by Gene DiLorenzo

“Due to heavy precipitation last month, water levels on Lake Alice were steadily increasing,” the DNR said in a statement. “When water levels became high enough that water was flowing over the dike between the lake and the St. Croix River, DNR staff opened the water control structure’s valve to release excess water from Lake Alice. Upon attempting to close the valve over the weekend, staff discovered the control structure closure mechanism had failed and was stuck open, which has caused the lake to drain.”

The abrupt disappearance of the lake resulted in numerous fish deaths and stranded many others in small pools of water. Several people were observed on Monday rescuing fish, carrying surviving fish from the lake remnant to the river.

Lake Alice is named for Alice O’Brien, daughter of park namesake William O’Brien. Alice O’Brien (1892-1962) donated the original 180 acres of land for the park in 1945. She drove her car across the United States at age 19, went to France during World War I to serve as a mechanic and nurse, traveled thousands of miles in China, Africa, and elsewhere, and worked for women’s suffrage and numerous philanthropic causes. (Source)

The DNR is alerting the public that the lake is not usable at this time and there is not yet a timeline for closing the valve and refilling the lake. Other activities, such as paddling, fishing, and boating on the St. Croix River, are not affected by the drawdown. Rentals of paddlecraft are still available. Updates will be available at mndnr.gov/obrien.

Thank you to St. Croix 360 reader Gene DiLorenzo for sharing his photos of the drained lake!