TRACKING MONTANA’S GROUNDWATER

Since 1993, the Montana Bureau of Mines and Geology (MBMG) has been monitoring groundwater levels in the State’s major aquifers. The monitoring network consists of more than 800 wells that provide data from unconfined alluvial, deep basin-fill, and deep confined bedrock aquifers across the State. Some of these wells have been consistently monitored since the 1950s. In addition to MBMG-serviced wells, the network consists of sites from several cooperators, including Tribes, other state and federal agencies, local water quality districts, and conservation districts.

In 2011, MBMG participated in the initial National Groundwater Monitoring Network (NGWMN) pilot study and became an NGWMN data provider in 2015. Currently, MBMG provides the NGWMN with water-level data from 206 sites and water-quality data from 54 sites.

The MBMG Data Center houses all groundwater information (water well construction details, lithologic descriptions, water levels, inorganic water quality, isotopic data, and site inventories). Data are made available to the public through various web services hosted on ESRI’s ArcGIS Server, Geoserver, or internally developed Application Programming Interface (API) access.

Groundwater levels in Montana’s aquifers vary seasonally, and from year to year in response to changing climatic conditions, nearby groundwater withdrawals, and changing land use. Data from the network highlight the importance of long-term, systematic, groundwater-level monitoring to 1) develop a comprehensive understanding of how aquifers respond to different stresses and 2) develop meaningful evaluations of the groundwater supply.