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The USGS works in collaboration with partners to monitor groundwater levels using the framework of the National Groundwater Monitoring Network (NGWMN).

The USGS works in collaboration with partners to monitor groundwater levels using the framework of the National Groundwater Monitoring Network (NGWMN). This collaborative groundwater network of Federal, State, and local agency data providers was authorized by the SECURE Water Act in 2009 and aims to build and refine a national network of wells that meet specific criteria related to quality, accessibility, density, and frequency of measurement criteria. Within the NGWMN, the USGS provides Federal support for a Climate Response Network (CRN) outfitted with continuous, real-time instrumentation that is designed to serve as a measure of groundwater conditions during drought and provide long-term groundwater levels.


Below, please find several highlights of recent groundwater monitoring accomplishments:

  • The NGWMN grew significantly during 2020. The size of the NGMWN grew from 9,248 sites in January 2020 to 18,235 sites in January 2021. Details on growth are described in the following bullets.
    • In 2020 a total of 7,040 groundwater level sites were added to the NGWMN, bringing the number of long-term water-level sites monitored to over 14,000 wells. This almost doubled the number of water-level sites in the NGWMN. Most of these wells were added as part of an effort to enhance the wells in the High Plains aquifer system to support the USGS High Plains Aquifer Assessment Study. 
    • In addition, 1,947 new water-quality sites were added to NGWMN bringing the total number of sites to nearly 4,000 wells and springs. This also almost nearly doubled the number of water-quality sites in the NGWMN. Most of these new sites are part of the USGS NAWQA Decadal Monitoring Network that were added to improve the coverage of the NGWMN water-quality monitoring network. 
  • In the past two years, three new data providers were added to the NGWMN bringing the total number of state providers to 37. Sites are present in all 50 states and three U.S. Territories and in 64 of the 67 principal aquifers.
  • The National Ground-Water Monitoring Network Data Portal has added the capability to calculate and display monthly water-level statistics. This can be used to help display the current condition of a site in a statistical context. These can be displayed for each site and can also be shown in map form using the ‘Layers’ tool. 
  • The USGS is instrumental in the distribution of water to citizens and commerce. In this video, Bill Eldridge of the Dakota Water Science Center explains the USGS’ recent role in finding, monitoring, and modeling groundwater reserves for the city of Sioux Falls, South Dakota. 
  • As part of the Next Generation Water Observing System (NGWOS) program, USGS scientists are using dense, distributed monitoring of soil moisture, in combination with monitoring of precipitation and groundwater levels, to understand recharge mechanisms at a Climate Response Network site in Pennsylvania. Internet of Things wireless technology is being tested to telemeter the data from the soil-moisture “pods” to the base station, from which the data are processed and served to the public. Watch USGS groundwater station 395512075293701 as installation and monitoring progresses. 
  • The Climate Response Network includes about 680 wells nationwide that report water-level conditions in near-surface aquifers that are minimally affected by anthropogenic influences. Of these 680 wells, about 245 produce data in real-time and are funded directly through GWSIP. In 2000, highest water levels on record were observed at 94 of the wells, and lowest water levels on record were observed at 19 wells. Collaborators include more than 100 federal, state, tribal, local, and university partners.
  • In accordance with P.L. 104-66, the USGS provided the latest biennial reports and associated water-level and water-level change maps for the High Plains aquifer (underlying Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming) to Congress.
  • The USGS is monitoring groundwater quality by use of real-time sensors in all parts of the United States and its territories. 
    • In Illinois, one of the big issues is high nitrate concentrations in water, and the USGS deployed real-time nitrate monitors over a period of two years (2017-2019) in both groundwater and nearby surface water to characterize the occurrence of nitrate in the flow system. See this report by Lance Gruhn and William Morrow, released in 2020. 
    • In California, the USGS monitored multiple wells at several depths to evaluate the relations between groundwater and oil resources. The data collected will help resource managers to understand the location of water resources, whether there is evidence of fluids from oil and gas sources in groundwater, and the pathways or processes that contribute to the mingling of water and petroleum resources. See this report by Rhett Everett and others, released in 2020. 

Additional groundwater monitoring efforts by the USGS include:


Stakeholder Quotes

“The National Groundwater Monitoring Program has allowed NH Geological Survey to provide New Hampshire’s Drought Management team better support for decision making.”
Gregory Barker, New Hampshire Geological Survey

“NGWMN funding helps ensure that Maryland will have reliable and accurate groundwater-level monitoring into the foreseeable future.” 
Andrew Staley, Maryland Geological Survey, Department of Natural Resources

“Participation in the NGWMN has significantly improved our network and our ability to disseminate groundwater data to the public.”
Brooke Czwartacki, South Carolina Department of Natural Resource

“Participation in the NGWMN allows the Montana Bureau of Mines and Geology to leverage limited state funds to upgrade monitoring infrastructure and improve the integrity of monitoring sites thereby improving the quality of data provided.”
John LaFave, Montana Bureau of Mines and Geology