Lake Hydrology Program


The Lake Hydrology Program exists to support the DNR Ecological and Water Resources director and staff by collecting and providing data on lake levels and other lake characteristics that are needed to effectively carry out the Division's statutory responsibilities and management programs.

The Director of DNR Ecological and Water Resources has been delegated authority from the DNR Commissioner for administering portions of the state water law contained in Minnesota Statutes, Chapters 103F and 103G, including authority to regulate work in public waters; control the appropriation and use of water; construct and operate dams and water level control structures; and conduct water resource surveys, investigations, and studies.

Minnesota Statutes, Section 103G.255, mandates the Commissioner administer the establishment, maintenance, and control of lake levels. MN Statutes, Section 103A.401 requires the Commissioner to establish and maintain a statewide water information system on the availability of waters of the state. A large number of other statutes and rules establish legal authorities and relate to the use made of the data from the Lake Level Minnesota Monitoring Program and Lakes-DB.

Clientele, products and services

A key component of the Lake Hydrology Program is the development and maintenance of the Lake Level Minnesota Monitoring Program. Lake Level Minnesota primarily uses both temporary (movable) and permanent lake gages as indicators for measuring and determining the water surface level of certain lakes. A network of approximately 1000 lake gages is currently managed. The program relies on over 700 citizen volunteers and local government partners who record lake levels on a regular basis and submit the data to DNR. Approximately 25% of the monitoring sites are managed currently under oral cooperative agreements with governmental units. DNR purchased three continuous water level gaging systems in 2005 - 2006 for installation on high profile lakes.

Primary clientele groups for the monitoring results are DNR technical staff, engineering firms, lake associations, lakeshore owners, researchers, and local governmental units including cities, counties, watershed districts/watershed management organizations, and SWCDs.

Water level data are used by DNR field staff as rationale for decision making in the public waters permit program and appropriations permit program from lakes. The records are used as supporting data for establishing ordinary high water levels and historic high water elevations, which are also the foundation for setbacks within the land use management programs. Lake level data support many DNR hydrologic and hydraulic analyses. A consistent record of lake levels provides a long-term indication and understanding of the hydrology of the lake, watershed, and the relation between surface water and ground water. Long-term records show normal fluctuations, as well as the extreme highs and lows. Data are used to calibrate hydrologic models, especially applications for flood levels and lake outlets. The information is crucial to surface water and ground water interaction studies for appropriations decisions.

The data are used by local zoning officials for platting, locating structure sites, and for establishing low floor elevations for new construction. Watershed managers and planners use historical lake level data while preparing local water management plans and modeling lake water quality characteristics. Fisheries staff use data as one variable in studying impacts on habitat. Other researchers use the data for climate change studies. Water level data are used for decisions by lakeshore owners on dock location/timing, vegetative shoreline protection, and understanding the natural fluctuations of a lake.

Primary products and services provided by the program include:

  • installation of the network of temporary lake level staff gages at locations convenient to volunteer readers and surveying/establishment of yearly zero elevations and applicable temporary benchmarks
  • receipt of lake level readings, data entry, and accurate maintenance of information for the statewide lake information database and subsequent use on the LakeFinder web site
  • training and technical assistance for volunteers and local units of government conducting lake level monitoring
  • responses to questions about data on the LakeFinder Lake Water Level Report page
  • individual lake level reports including graphs, tabular lists, and summaries of lake information
  • creation of customized databases or Excel spreadsheets and graphs of available lake information
  • data submissions to the Water Year Data Summary biennial report
  • research results from DNR historical lake files and survey notes

Requests for information and these services are usually initiated by email or a phone call to Lake Hydrology staff.

Requests and rationale to add new lakes to the gaging network are initiated through the DNR Area Hydrologist, approved by the Regional Waters Manager, and approved/assigned by the Monitoring and Database Management Unit Supervisor.


Information management

The Lake Hydrology Program manages the DNR Waters computer database for lake information called Lakes-DB. Lakes-DB provides a tool for storing and retrieving a variety of information on Minnesota's lake basins. The lake level readings and reading date that are received from the Lake Level Minnesota volunteers are entered into Lakes-DB.

The LakeFinder web site is the best means for the public to access available data on more than 4,500 Minnesota lakes and rivers relating to fisheries information, lake area and maximum depth, depth maps, lake water levels, water quality and clarity, air photos, and topographic maps. After searching by county, lake name, or identification number for a particular lake, the selected Lake Water Level report page contains information from Lakes-DB, including:

  • reported historical and current lake levels
  • period of record and number of readings
  • highest recorded lake level
  • highest known lake level
  • lowest recorded lake level
  • recorded range
  • average water level of reported readings
  • ordinary high water level [also shown as the red line on the 10-year graph]
  • datum
  • benchmarks
  • most recent 10-year graph [X-axis Year tick mark references mid-year]

About 1,300 of the lakes have a historical record of more than 100 water level readings. A LakeFinder user can retrieve and view all the reported lake elevations for a specific lake via the download of lake level data as dBase or ASCII from the Lake Water Level report page. ASCII is the most common method used to view the data. The chronological water surface elevation data can then be saved or copied into a computer software spreadsheet for sorting and graphing. We ask that a user not change the raw data numbers/dates, and that DNR Waters Lake Level Minnesota Monitoring Program is credited as the data source for any publications or reports.

Staff is also able to provide additional information from Lakes-DB on lake data elements such as:

  • lake name, alternate names, identification number, and location
  • gage zero elevation and date last checked
  • gage location
  • type, location, and elevation of outlet
  • additional benchmark information
  • shoreline length


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