Outlet Channel









Maintaining an unimpeded flow from Big Marine Lake through Little Carnelian Lake and the outlet pipe to the St. Croix River is a critical responsibility of the Watershed District.. CMSCWD was formed to reduce the threat of flooding in Big Marine and Carnelian Lakes and the solution was the result of many years of study of the causes to these water fluctuations.  Some of the reports that examine the causes of these water fluctuations are:

Natural Ordinary High Water Investigation for Big Marine Lake,
MN DNR, May, 1976
Big Marine Drainange Feasibility- Drainage of Big Marine Lake, TKDA Engineering, February 21, 1984
Hydrologic Factors Affecting Lake Level Fluctuations in Big Marine Lake, USGS
Big Marine Lake Hydrologic Study, MN DNR, April 1994

The range of elevations that the District maintains is a result of negotiations with riparian property owners and the Department of Natural Resources to both protect property and protect wetlands within the watershed.  The only variable in the system is an adjustable weir downstream of the fixed outlet and Turtle Lake.  The current management plan for the weir has evolved over the years and was approved by the Board of Managers on April 12, 2017 after receiving considerable public input. The management plans are available for review here, from the current plan to the original management plan:

2017 Turtle Lake Management Plan (current)
2004 Turtle Lake Management Plan 
1998 Turtle Lake Management Plan
1985 Turtle Lake Management Plan


Big Marine Lake Outlet Elevations

Yellow designates at or over weir elevation

(Turtle Lake Stop Log status)

  Big Marine Outlet Fixed Weir Overflow elevation is 940.8 feet


Location Water Surface Elevation
04/01/20 Big Marine Outlet 941.06
04/01/20 Mud Wetland 940.68
04/08/2020 Big Marine Outlet 941.04
04/08/2020 Mud Wetland 940.58
04/21/2020 Big Marine Outlet 940.88
04/21/2020 Mud Wetland 940.28
5/12/2020 Big Marine Outlet 940.72
05/12/2020 Mud Wetland 939.92
5/29/2020 Big Marine Outlet 941.02
5/29/2020 Mud Wetland 940.72
6/9/2020 Big Marine Outlet 940.86
6/9/2020 Mud Wetland 940.66
6/22/2020 Big Marine Outlet 940.76
6/22/2020 Mud Wetland 940.56
7/7/2020  Big Marine Outlet 941.04
7/7/2020 Mud Wetland 941.02
7/10/2020 Big Marine Outlet 941.0
7/10/2020 Mud Wetland 940.98
7/14/2020 Big Marine Outlet 940.94
7/14/2020 Mud Wetland 940.92
7/21/2020 Big Marine Outlet 941.04
7/21/2020 Mud Lake Wetland 941.02
2018 Data
2017 Data
2016 Data

Pages 22 through 29 in Section IV of the Management Plan discusses the maintenance activities in further detail.