The low-flow gate on the Prior Lake Outlet Structure was closed this week. Prior Lake’s level was 902.61 feet above sea level and dropping as of April 29 and the District is required to close the low-flow gate by May 1.
The main gate of the outlet structure remains open as usual and water will continue to discharge from Prior Lake as long as the lake is above the elevation of the outlet’s weir at 902.5 feet above sea level. Current lake levels can be found here.
The low-flow gate was to opened in March to provide some extra storage on Prior Lake heading into the spring melt season. The District has permission from the Minnesota DNR to open the low-flow gate in March and April when necessary.
The low flow gate operates best when the lake level is between 902.0 and 903.0 and is managed based on the District’s outlet operations policy which is approved by the DNR. The Prior Lake Outlet Structure automatically stops discharging when the lake level drops below 902.5 feet. When the low-flow gate is open, lake levels can drop slightly faster and to (no lower than) 902.0 feet. When the lake is above 903’, the low-flow gate is ineffective as the outlet pipe is limiting the amount of flow leaving the lake.
For more information on the outlet structure and the low-flow gate check out the StoryMap on our website here.