The Minnehaha Creek Watershed District’s water quality lake grading method was developed in 1989. The lake grade shows how one lake measures up compared to other area lakes and indicates the perceived condition of the open water. Three water quality measurements are combined to create each lake grade. However, there are also other factors that contribute to lake condition, including precipitation. aquatic plants, fisheries, harmful chemicals, and over-use.

Understanding Lake Water Quality Grades

The grades consider what is average or normal for lakes in a given area. What is a “C” in one part of the country might not be a “C” elsewhere. However, within the seven-county metro area, grades can be compared.

The Minnehaha Creek Watershed District has 11 subwatersheds that make up the whole watershed. The Minnehaha Creek Watershed District’s Hydrodata Program (i.e., water quality data) is using a subwatershed monitoring approach to diagnose the health of the District’s waters in a more in depth approach. The subwatershed monitoring plan focuses on 2 or more individual subwatersheds for 3 consecutive years by monitoring the nutrients, water clarity, physical parameters (i.e., temperature, dissolved oxygen, depth contours, etc), and biological communities (i.e., aquatic plants, invasives species, macroinvertebrates).  The subwatershed monitoring plan is on a 10 year cycle, so subwatersheds whose monitoring began in 2016 will be monitored again starting in 2026. This in depth monitoring will expose areas of concern in each subwatershed and allow the District to target the areas that may need restoration or remediation.

The following is a list of MCWD lakes. The lakes that have been or are currently being monitored have recieved a lake water quality grade. The lake water quality grades have been posted for the past ten years.

For more information on the lake water quality grades go to Understanding Lake Water Quality Grades.

Upper Watershed Lakes: 

Minneapolis Chain of Lakes:

Limited Access Lakes:

The following is a list of MCWD lakes and streams. The past and current lake water quality monitoring sites are posted.

Lakes

The following is a list of MCWD lakes. The lakes that have been or are currently being monitored have recieved a lake water quality grade. The lake water quality grades have been posted for the past ten years.

For more information on the lake water quality grades go to Understanding Lake Water Quality Grades.

Continuous Water Level Recorders

MCWD uses pressure transducers (aka Level TROLLs) to measure stream stage in stilling wells located next to the streams.  The stream stage or water level is then used to calculate discharge of a stream. There are currently 9 units at various locations within the watershed.  This data is crucial for the calibration of the District's XP-SWMM model.

Stormwater Sampling

In addition to recording continuous stage measurements, at some of the stream locations, the  Level TROLLs are connected to equipment that collects  stormwater samples.  When the Level TROLLs detect a determined amount increase in stream stage within 30 minutes, equipment is triggered at the end of the storm event, the samples are collected immediately and sent off for analysis (TP and TSS).  The resulting event mean concentration (EMC) is crucial for the calibration of the District's PLOAD model. 

Telemetry

In 2007, the MCWD successfully installed land line phone telemetry at 3 locations along Minnehaha Creek, including the Grays Bay outfall (CMH07), I-494 ramps (CMH19), and the Browndale Dam (CMH03).  The data is transmitted back every 2 hours from Grays Bay and one daily download at I-494 and Browndale Dam to a designated MCWD computer at the office, allowing broadcast of 1) Lake Minnetonka water level, 2) discharge out of the Grays Bay Dam, and 3) discharge out of the Browndale Dam.  In 2013, the land lines will be updated with cellular modems.  The data collected provides  more accurate information for the public regarding discharge levels and recreational safety along the entire length of Minnehaha Creek (in combination with the Web broadcast of discharge at Hiawatha Avenue provided by the USGS).  The information will also be useful in determining the best method to regulate discharges coming out of the Grays Bay Dam for recreational use and prevention of downstream flooding.

In cooperation with the Minnetonka Yacht Club, a weather station was installed on Lighthouse Island on Lake Minnetonka’s Carsons Bay during summer 2008. The weather station measures radiation, relative humidity, temperature, precipitation, wind direction, and speed. A webcam captures views of Lake Minnetonka from Lower Lakes and Big Island.

The Minnehaha Creek Watershed District compiles water quality monitoring data for lakes and streams in an annual monitoring report. The information and data used to calculate water quality lake grades are included in the yearly report. The official title of MCWD’s monitoring reports is the Annual Hydrological Monitoring Report.

To view the Annual Hydrological Monitoring Report for a certain year, click on the year below. The Annual Hydrological Monitoring Reports for the years 1989-1991 are not available. Wenck Associates Inc. states that data was collected but there were no report published 1989-1991.