Description: This point layer shows the maximum recorded Arsenic sample result (ug/L) for wells in the Minnesota County Well Index. Only wells with known Arsenic sample results are included. Unique well numbers are not included in this layer.
Data Source: Not available for download.
Copyright Text: Minnesota Department of Health (MDH)
Description: This point layer shows the maximum recorded Nitrate sample result (mg/L) for wells in the Minnesota County Well Index. Only wells with known Nitrate sample results are included. Unique well numbers are not included in this layer.
Data Source: Not available for download.
Copyright Text: Minnesota Department of Health (MDH)
Description: The Drinking Water Supply Management Area (DWSMA) is the Minnesota Department of Health (MDH) approved area delineated using identifiable landmarks that reflects the scientifically calulated wellhead protection area boundaries as closely as possible (Minnesota Rules, part 4720.5100, subpart 13)
Copyright Text: Minnesota Department of Health, Environmental Health Division, Drinking Water Protection Section, Source Water Protection Unit
Description: Drinking water supply management area (DWSMA) vulnerability is an assessment of the likelihood that the aquifer within the DWSMA is subject to impact from land and water uses within the wellhead protection ares. It is based upon criteria that are specified under Minnesota Rules, part 4720.5210, subpart 3.
Copyright Text: Minnesota Department of Health, Environmental Health Division, Drinking Water Protection Section, Source Water Protection Unit
Name: Surface Water DWSMAs (DWSMA-SW) Legacy- Priority Areas A & B
Display Field: dsw_name
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: The drinking water supply management area for a surface water intake (DWSMA-SW) is the surface and subsurface area surrounding a public water supply intake that contains the scientifically calculated surface water protection area and is managed by the entity identified in a surface water protection plan. The boundaries of a DWSMA-SW are delineated by identifiable physical features, landmarks or political and administrative boundaries. Each delineation includes Priority Areas A & B. Priority Area A is delineated starting with an 8-hour time of travel and is intended to manage contaminants that could present an acute (immediate) health concern to water users; Priority Area B is a larger area delineated to manage contaminants that could cause longer-term health effects at lower levels. Priority A and B areas have not been completed for all DWSMA-SW systems. This layer includes A and B areas for Minneapolis, St. Paul and St. Cloud and only.
Data Source: The source data and metadata are available for download through the Minnesota Geocommons website (https://gisdata.mn.gov/dataset/water-mgmnt-area-surface-water).
Copyright Text: Minnesota Department of Health (MDH)
Description: Under the Groundwater Protection Rule, the MDA determines the mitigation levels for community water supply wells and their Drinking Water Supply Management Areas (DWSMAs) that have nitrate levels greater than or equal to 5.4 mg/L (or parts per million (ppm)), based on monitoring data provided by MDH. Under the Rule, wells which have nitrate levels at or above 5.4 ppm but less than 8 ppm at any point in the previous ten years will be determined to be at Mitigation Level 1 and wells with nitrate at or above 8 ppm at any point in the last ten years will be determined to be at Mitigation Level 2, unless the MDA determines there is a point source causing the well to exceed these levels or the MDA delays the determination of a mitigation level decision for good cause.
Data Source: More information on mitigation level determination can be found on the Minnesota Department of Agriculture website (https://www.mda.state.mn.us/mitigation-level-determination).
Copyright Text: Minnesota Department of Agriculture (MDA)
Name: Special Well and Boring Construction Areas (SWBCA)
Display Field: swc_name
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: The improper location, construction or sealing of a well or boring in an area of groundwater contamination may allow contaminants to spread to otherwise protected aquifers. The designation as a special well and boring construction area alerts the public, including property owners, drilling contractors, and local officials, to the occurrence of groundwater contamination, and the need to place special controls on the drilling of new wells and the modifications of existing wells. It provides information on the contamination source, contaminants encountered, aquifers affected, and necessary restrictions. It also allows affected parties, including local units of government, to be aware of and to respond to the contamination problem.The rules pertaining to the construction of wells and borings place minimum restrictions on the location, construction, repair, and sealing of wells and borings. Special construction requirements are authorized in rule and statute in areas of known or suspected contamination. In order to provide safe water it may be necessary to require the construction of deeper wells, employ special construction techniques, conduct specialized testing, or require special water treatment procedures. Contractors proposing to drill any well or boring in an advisory area must contact the Minnesota Department of Health, Well Management Section prior to construction. Contractors and property owners must submit a written request and well construction plan to the MDH and must receive written approval before construction, repair, or sealing of a well in the special well and boring construction area.
A Special Well and Boring Construction Area is sometimes also called a well advisory. It is a mechanism which provides for controls on the drilling or alteration of public and private water-supply wells, and monitoring wells in an area where groundwater contamination has, or may, result in risks to the public health. The purposes of a Special Well and Boring Construction Area are to inform the public of potential health risks in areas of groundwater contamination, provide for the construction of safe water supplies, and prevent the spread of contamination due to the improper drilling of wells or borings.
Copyright Text: Minnesota Department of Health (MDH)
Description: The MDA Township Testing Program tests private wells for nitrate in areas of the state with the greatest potential for nitrate contamination. The initial results represent what people are drinking regardless of well type or well age and nitrogen source(s). The percentage value shown in the legend for this layer reflects the percentage of wells by township included in the initial dataset that have nitrate values at or above the drinking water standard of 10 ppm. The data provides an important indication of areas with the greatest concerns for elevated nitrate in private wells. Data source: More information on the Township Testing Program can be found on the Minnesota Department of Agriculture website (https://www.mda.state.mn.us/township-testing-program).
Copyright Text: Minnesota Department of Agriculture (MDA)
Description: The MDA Township Testing Program tests private wells for nitrate in areas of the state with the greatest potential for nitrate contamination. The initial results include data from all wells initially tested regardless of well construction or nitrogen source. Final results are determined using two rounds of sampling and a process to remove wells with construction concerns, insufficient construction information and those near potential non-fertilizer sources of nitrate. In many cases wells are removed from the final data set because homeowners didn’t participate in the second round of testing. Final results represent wells that are potentially impacted by a fertilizer source. Townships with less than 20 wells in the final dataset were determined to have insufficient data to characterize the water quality for a township. The percentage value shown in the legend for this layer reflects the percentage of wells by township included in the final dataset that have nitrate values at or above the drinking water standard of 10 ppm.
Data source: More information on the Township Testing Program can be found on the Minnesota Department of Agriculture website (https://www.mda.state.mn.us/township-testing-program).
Copyright Text: Minnesota Department of Agriculture (MDA)
Description: This polygon layer displays the number of drinking water wells (as defined in the Minnesota County Well Index) within each Public Land Survey section.
Data Source: Not available for download.
Copyright Text: Minnesota Department of Health (MDH)
Description: County Well Index (CWI) location-verified and interpreted well records were summarized by PLS section. Results show the general distribution of aquifer use in the state. Classification is based on the aquifer code with the greatest frequency in each section; in cases where multiple aquifer codes have the same count, classification between those codes is arbitrary:
• Surficial sand and gravel – aquifer close to the land surface. Like a sandbox, vulnerable to contamination due to lack of overlying fine-grained material; recharges quickly
• Buried sand and gravel – aquifer not close to the land surface, less vulnerable to contamination due to presence of overlying – fine-grained material; recharges slowly
• Sandstone bedrock – aquifer typically not close to the land surface, contamination vulnerability depends on composition and thickness of overlying material
• Carbonate bedrock (limestone) – aquifer often close to the land surface, contamination vulnerability depends on composition and thickness overlying material. Because carbonate bedrock dissolves over time, water can move quickly over long distances through conduits and caves and is highly vulnerable to contamination in near-surface conditions.
o see areas mapped as karst on GRAPS Pollution Sensitivity of Near-Surface Materials
• Crystalline bedrock – aquifer often close to the land surface, contamination vulnerability depends on overlying material. The rock itself is relatively impermeable, so water moves through fractures only; wells can have low yields and be vulnerable to contamination.
o See areas in northeastern and southwestern Minnesota mapped as bedrock at or near surface on GRAPS Pollution Sensitivity of Near-Surface Materials
• Weathered material – aquifer typically not close the land surface, less vulnerable to contamination due to presence of overlying fine-grained material. Water quality can be highly mineralized; used as an aquifer because of no overlying sand and gravel; recharges slowly
Data source: Not available for download
Copyright Text: Minnesota Department of Health (MDH)
Name: Pollution Sensitivity of Near-Surface Materials
Display Field: value
Type: Raster Layer
Geometry Type: null
Description: This dataset estimates the pollution sensitivity of near-surface materials (soil, bedrock, aquifer) from the transmission time of water through 3 feet of soil and 7 feet of surficial geologic material, to a depth of 10 feet from the land surface. This layer is used to derive the watershed health index score that shares the same name. Sensitivity ratings range from high (indicating coarse-grained material such as sand) to ultra-low (indicating fine-grained material such as silt or clay), as well as categories for special near-surface conditions (karst, bedrock, etc.).
Data Source: The source data and metadata are available for download through the Minnesota Geocommons website.
Copyright Text: Minnesota Department of Natural Resources (MN DNR)
Description: Pollution sensitivity (also known as aquifer vulnerability or geologic sensitivity) refers to the time it takes recharge and contaminants at the ground surface to reach the underlying aquifer. This raster layer was created by calculating the sensitivity at individual wells and then interpolating between them to create a smooth layer. The wells used to make this figure vary in depth but overall provide a picture of the geologic sensitivity of aquifers below the water table. (This method was employed due to the absence of an available statewide dataset depicting pollution sensitivity, or vulnerability, of aquifers.)
Data Source: Not available for download.
Copyright Text: Minnesota Department of Health (MDH)