Montana in the National Ground-Water Monitoring Network
The MBMG shares data through its Ground Water Information Center (GWIC) website (http:// mbmggwic.mtech.edu/), and web mapping applications. Data also are available through web services hosted on ESRI’s ArcGIS Server or Geoserver.
The MBMG selected its NGWMN wells based on Framework Document and “Tip Sheet” guidance available from the NGWMN web page (http://cida.usgs.gov/ngwmn/learnmore.jsp). Candidate wells had at least five years of water-level record and a monitoring frequency of at least quarterly. Other criteria included the aquifer extent, groundwater development, flow system position, and monitoring well density.
The selection process identified 227 wells for inclusion in the NGWMN. Each well’s hydrograph was evaluated against local hydrogeologic and land-use data to assign it to a Background, Suspected Changes, or Documented Changes subnetwork. Most wells show little-to-no anthropogenic influence and became part of the Background subnetwork. Hydrographs with anthropogenic signals (Documented Changes subnetwork) showed:
- Seasonal irrigation recharge—mostly from the irrigated alluvial aquifers.
- Seasonal irrigation withdrawals—mostly from the irrigated intermontane basins and buried glacial aquifers.
- Long-term depletion—locally from the upper Cretaceous Fox Hills-Hell Creek aquifer system in eastern Montana.
Data from Montana NGWMN wells are available through the NGWMN Data Portal (https://cida. usgs.gov/ngwmn/).