Aquifer Delineation and Aquifer Materials Mapping
Improved aquifer boundaries for shallow and buried aquifers must be delineated in the state to enhance aquifer management and protection abilities. Existing geology maps, cross sections, test hole and well data, and aerial photography, often times in conjunction with drilling, well installation, water-level measurement, and water sampling, will be used to delineate aquifer boundaries at a scale of 1:100,000. The aquifer boundaries will be incorporated into a GIS so they can be integrated with other environmental data sets.
Why is aquifer delineation needed?
Previously published reports and maps were drafted with significantly less subsurface data at the time, and with the SD Geological Survey actively drilling test holes and observation wells, the aquifer boundaries are constantly shifting due to newly collected subsurface data. Aquifers of various depths are used for drinking water and in many cases are the only options for public and private water supplies. The need for reliable information on aquifers will become most critical during times of drought when decreases in water levels and water yield may occur. Maps of this type will aid in addressing water supply issues. With DANR's Water Rights program relying on accurate aquifer boundaries to allocate water permits, the need for high accuracy aquifer maps is vital for the aquifer's health so that no over-pumping is occurring.
Aquifer Materials Mapping
Aquifer material maps show areas in the subsurface that contain aquifer materials. Subsurface materials that are porous such as sand or gravel, which acts as a reservoir for liquids, are classified as aquifer materials. The aquifer materials are categorized by depth intervals consistent with the state's General Water Pollution Control Permit for Concentrated Animal Feeding Operations. The map does not show individual aquifers but instead shows the first type and depth of mappable aquifer material to be encountered.
Why is an Aquifer Materials Map needed?
- Environmental issues such as source water protection, aquifer contamination, water availability and development, concentrated animal feeding operations, and non-point source pollution require that areas underlain by aquifers be accurately defined.
- Shallow aquifers in the state are used extensively for drinking water supplies. It is necessary to define the boundaries of these aquifers in order to protect these drinking water supplies.
- South Dakota Codified Law 34A-3A-24 places restrictions on the location of concentrated animal feeding operations. Shallow aquifer materials maps are needed to assist in implementing this law.
- Aquifers of various depths are used for drinking water and in many cases are the only options for public and private water supplies. The need for reliable information on aquifers will become most critical during times of drought when decreases in water levels and water yield may occur. Maps of this type will aid in addressing water supply issues.
Who would use an Aquifer Materials Map?
These maps are being produced in response to a need for maps depicting the depth from land surface to the first mappable aquifer material. This type of information is needed by the public and by DENR regarding South Dakota's General Water Pollution Control Permit. The information is also needed by county and municipal governments to more effectively address other land-use decisions.
Learn more about South Dakota aquifers
Status Map (Click map for full pdf)