Geologists in the Minnesota Department of Natural Resources’ (DNR) Aggregate Resource Mapping Program completed three new resource maps showing the potential for sand and gravel deposits, as well as crushed stone resources, in Swift, Sibley and Redwood counties. Aggregate resources are a critical natural material needed to construct roads, bridges, trails and buildings.
Datasets for all three county projects, including maps to locate aggregate resources and a countywide gravel pit survey, will be publicly available this fall on the DNR’s online interactive mapping website. The online publishing dates for the datasets are as follows:
- Swift County will be posted on Sept. 20.
- Sibley County will be posted on Sept. 27.
- Redwood County will be posted on Oct. 4.
The sand and gravel maps are the most recent products from the DNR that provide field-researched information to help land use planners, industry, and others make informed decisions on how to maintain access to and best use these resources for local infrastructure and construction needs.
About half of all aggregate resources used in Minnesota go toward publicly-funded infrastructure projects. In areas of the state that have a scarcity of aggregate resources, local officials can use aggregate maps to inform land use decisions and to ensure that sand and gravel deposits remain accessible and affordable for future generations of construction projects.
DNR geologists use geologic mapping techniques like field surveys and drilling combined with computer programs to find sand, gravel, and crushed stone resources and characterize the quality of a deposit.
Almost all the accessible aggregate resources in Swift, Sibley and Redwood counties were deposited more than 10,000 years ago, when meltwater streams from glacial land formations deposited sand and gravel in different areas of the state.
“Aggregate resources are found where nature put them, and every county’s unique landscape hosts different amounts of accessible sand and gravel,” said Chad Crotty, DNR aggregate geologist. “It’s important to know where local deposits are in order to preserve and conserve this nonrenewable resource.”
The DNR will continue to work on multiple aggregate map projects
The Minnesota Legislature established the DNR’s Aggregate Resource Mapping Program in 1984. The goal of the program is to complete detailed aggregate maps for every county statewide. Today, 21 Minnesota counties have access to completed aggregate resource maps.
A three-year grant from the Minnesota Environment and Natural Resources Trust Fund, as recommended by the Legislative-Citizen Commission on Minnesota Resources, provided funding for aggregate resource mapping in Kandiyohi, Redwood, Swift and Sibley counties. Additional funding provided by LCCMR will allow the DNR to complete more aggregate resource maps in the next few years.
For more information, visit the Aggregate Resources Mapping page [https://www.dnr.state.mn.us/lands_minerals/aggregate_maps/index.html] of the DNR website.