A spring is a focused, natural discharge where water emerges from the ground.
Springs are important water sources for coldwater streams (trout streams), cool and warm water streams, and lakes and ponds. They also sustain unique ecological habitats and have aesthetic and historical value that creates a special "sense of place" for local residents and visitors.
Minnesota Spring Inventory
The Minnesota Spring Inventory (MSI) provides a statewide spatial database with information from historical records, field analysis, and citizen input. We need the help of citizens to expand on our current knowledge. You can report spring locations from your mobile device or home computer with the MSI Reporting App.
Springsheds are areas within groundwater and surface water basins that contribute discharge to springs.
Understanding the extent of springsheds is important for the protection of the groundwater supply to springs. This involves determining the size of the land area that contributes to spring discharge, which can encompass both a surface watershed and an underlying groundwatershed. The boundaries of groundwater springsheds do not necessarily correspond to those on the land surface and are dynamic in their areal extent, changing as groundwater levels rise and fall.
Groundwater tracing, most often using fluorescent dye, is used to track groundwater flow and delineate springsheds. The Minnesota Groundwater Tracing Database (MGTD) provides access to dye trace reports, related publications, GIS files, and an interactive web map application.
Karst is a terrain with distinctive landforms and hydrology created primarily from the dissolution of soluble rocks. It is characterized by sinkholes, caves, springs, and underground drainage dominated by rapid conduit flow.
In karst, water dissolves fractures and joints in the bedrock forming a network of interconnected underground conduits that can carry groundwater long distances at speeds up to miles per day. Sinkholes, blind valleys, karst windows and springs are found on the land surface above underground karst systems and are thought of as surface expressions of karst or "karst topography." Karst also occurs in areas with few or none of these land surface features and therefore the absence of these features does not imply the absence of karst.
Karst Feature Inventory Points
A karst feature database of southeastern Minnesota displays sinkhole and other karst feature distributions across existing county boundaries in a GIS environment.
- GIS data is available on the Minnesota Geospatial Commons.
Minnesota Regions Prone to Surface Karst Feature Development, GW-01
Areas prone to the development of karst features within 50 feet of the surface. GIS data can be used alone or in conjunction with the Karst Feature Inventory Points.
Karst Landscapes and Geomorphic Units
Karst landscapes and geomorphic unit maps can be used to help identify the groundwater characteristics beneath, since classic signs of karst (springs, sinkholes, and sinking streams) are not always present at the surface. Landscape and geomorphic units include the land surface and the connections to underlying aquifers.
- Karst Hydrogeomorphic Units of Mower County
Units are categorized into eight unique geomorphic terrains based on their hydrology, form, and geology and are useful for water and land use planning and management.
- Karst Hydrogeomorphic Units, Plate 10 in Geologic Atlas of Mower County, Minnesota
- Karst Landscape Units of Houston and Winona Counties, GW-06
Units are categorized into karst, pseudokarst, or nonkarst based on their hydrology, form, and geology and are useful for water and land use planning and management.
Video Animations of Groundwater Flow in Minnesota Karst Settings
Short videos use realistic graphics, animation, and aerial footage to illustrate the unique geologic features, the complex movement of water to bedrock aquifers and streams, and the vulnerability to contaminants like nitrate-nitrogen (nitrate).
More videos and graphics can be found on the Minnesota Department of Agriculture site: Southeast Minnesota Groundwater Resources.