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Welcome to the National Ground-Water
Monitoring Network (NGWMN)
The National Ground-Water Monitoring Network (NGWMN) is a compilation of selected groundwater monitoring wells from Federal, State, and local groundwater monitoring networks across the nation.
The NGWMN Data Portal provides access to groundwater data from multiple, dispersed databases in a web-based mapping application. The portal contains current and historical data including water levels, water quality, lithology, and well construction.
To learn more about the network and data portal click here.
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Sites in the NGWMN are classified as being part of either the water-level network, the water-quality network or both.
Sites in the water-level network will be designated as being in one of three subnetworks. These are 1) the Background subnetwork, 2) the Suspected Changes subnetwork, and 3) the Documented Changes subnetwork.
You can select one or more Water-Level Monitoring Categories as a filter criteria.
Monitoring points that provide data from aquifers or parts of aquifers with no (or minimal) anthropogenic effects.
Monitoring points that provide data from aquifers or parts of aquifers that may have been affected by man's activity, but that is not documented or conclusive.
Monitoring points that provide data from aquifers that have documented anthropogenic effects.
Wells are assigned a monitoring category (Trend or Surveillance) depending on the purpose of the monitoring at the well.
You can select one or more Water-level Monitoring Categories as a filter criteria.
Surveillance monitoring would be used in conjunction with Trend monitoring to periodically provide a more detailed spatial snapshot of ground-water conditions. The frequency of Surveillance monitoring generally is much less than Trend monitoring.
Trend wells are generally monitored to determine changes over time. The frequency of monitoring depends on the hydrologic conditions of the aquifer and may vary.
Special studies monitoring is optional and would most often be associated with the Suspected or Documented Changes Subnetworks to evaluate the status of at risk ground-water resources. The monitoring frequency would vary, depending on the study.
Sites in the NGWMN are classified as being part of either the water-level network, the water-quality network or both.
Sites water-quality network will be designated as being in one of three subnetworks. These are 1) the Background subnetwork, 2) the Suspected Changes subnetwork, and 3) the Documented Changes subnetwork.
You can select one or more Water-Quality Subnetwork Categories as a filter criteria.
Monitoring points that provide data from aquifers or parts of aquifers with no (or minimal) anthropogenic effects.
Monitoring points that provide data from aquifers or parts of aquifers that may have been affected by man's activity, but that is not documented or conclusive.
Monitoring points that provide data from aquifers that have documented anthropogenic effects.
Wells are assigned a monitoring category (Trend or Surveillance) depending on the purpose of the monitoring at the well.
You can select one or more Water-Quality Monitoring Categories as a filter criteria.
Surveillance monitoring would be used in conjunction with Trend monitoring to periodically provide a more detailed spatial snapshot of ground-water conditions. The frequency of Surveillance monitoring generally is much less than Trend monitoring.
Trend wells are generally monitored to determine changes over time. The frequency of monitoring depends on the hydrologic conditions of the aquifer and may vary.
Special studies monitoring is optional and would most often be associated with the Suspected or Documented Changes Subnetworks to evaluate the status of at risk ground-water resources. The monitoring frequency would vary, depending on the study.
All NGWMN sites are associated with a single U.S. principal aquifer. Information on Principal Aquifers is available here.
You can select one or more Principal Aquifers as a filter criteria. Only those Principal Aquifers that have sites associated with the aquifer are shown in the selection list.
Each NGWMN site is associated with an agency. This could be the agency that samples the data or the agency that provides the data.
You can select one or more Contributing Agencies as a filter criteria. Only agencies that have sites associated with them are shown in the selection list.
This filter restricts sites based on the data that is actually available for the sites on the portal; Water Level, Water Quality, or Well Logs. Selecting more than one of three filters will show only sites that have all types of data available. For example, sites with both water-level data and well logs.
You can select one or more states as a filter criteria.
Alternatively, you can select one state and then select one or more counties within that State to be used as a filter criteria. Only those states and counties with the states that have sites associated with them are shown in the selection list.
Type of groundwater site (Well or Spring).
The aquifer codes are mapped to a generalized lithologic code to allow the user to select on the general type of aquifer.
Characteristic of the type of aquifer that the well is completed in (Confined or Unconfined). For the NGWMN, shallow semi-confined wells can be considered to be unconfined if they respond to climatic fluctuations in a relatively short period of time. Can select for Unconfined or Confined aquifers using this filter.
