Groundwater data is shown by data collection periods including real-time, monthly, and semiannual measurements for confined wells. A summary of the monthly groundwater conditions are explained in the monthly water conditions summary.
- Real-time: Most wells measured every 30 minutes
- Monthly climatic or water table wells: End of month measurement used to assess response to climatic conditions.
- Confined aquifer wells: Measured semiannually in September and April
- Groundwater network wells: Includes real-time, monthly, water table wells and confined aquifer wells.
Groundwater levels measure the depth to the water table in the aquifer. Wells access the aquifers, which are differentiated as unconfined, water table aquifers and confined aquifers.
Additional groundwater data is available at: http://waterdata.usgs.gov/md/nwis/gw