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Long-term monotonic trends in annual groundwater level metrics in the United States through 2020 (ver.2.0, January 2025)

Metadata Updated: February 21, 2025

The U.S. Geological Survey (USGS) Water Resources Mission Area (WMA) is working to address a need to understand where the Nation is experiencing water shortages or surpluses relative to the demand by delivering routine assessments of water supply and demand. A key part of these national assessments is identifying long-term trends in water availability, including groundwater and surface water quantity, quality, and use. This data release contains Mann-Kendall monotonic trend analyses for annual groundwater metrics at 54,932 wells located in the conterminous United States, Alaska, Hawaii, and Puerto Rico. The groundwater metrics include annual mean, maximum, and minimum water level and the timing of the annual maximum and minimum groundwater level. These metrics are computed from groundwater water levels from publicly available data from the National Water Information System (NWIS), the National Groundwater Monitoring Network (NGWMN) and the California Open Data Portal. Trend analyses are computed using annual groundwater metrics through the water year, which is defined as the 12-month period October 1, for any given year through September 30 of the following year (for example, October 2019 through September 2020). Trends at each well are available for up to four different periods: i) the longest possible period that meets completeness criteria at each well, (ii) 1980-2020, (iii) 1990-2020, (iv) 2000-2020. Annual mean, maximum, and minimum water-level metrics for wells screened in unconfined aquifers were determined only when a well's water-level time series was at least 70 percent complete. Additionally, each of these time series must have at least 70 percent complete records in the first and last decade. All longest possible period time series for wells in unconfined aquifer must be at least 10 years long and have annual metric values calculated for at least 70% of the years of the record. Annual mean, maximum, and minimum water-level metrics for wells screened in confined aquifers were determined only when a well's water-level time series was at least 50 percent complete. Additionally, each of these time series must have at least 50 percent complete records in the first and last decade. All longest possible period time series for wells in confined aquifer must be at least 10 years long and have annual metric values calculated for at least 50% of the years in the last 10 years of the record. Caution must be exercised when utilizing monotonic trend analyses conducted over periods of up to several decades (and in some places longer ones) due to the potential for confounding deterministic gradual trends with multi-decadal climatic fluctuations. This data release contains: six input files: NGWMN_gwl_meta_v2.0.csv, the metadata from the National Groundwater Monitoring Network NGWMN_gwl_data_v2.0.csv, the groundwater water level data from the National Groundwater Monitoring Network NWIS_gwl_meta_v2.0.csv, the metadata from the National Water Information System NWIS_gwl_data_v2.0.csv, the groundwater water level data from the National Water Information System CA_measurements_v2.0.csv, the groundwater level data from the California Open Data Portal CA_stations_v2.0.csv, the groundwater metadata from the California Open Data Portal two output files: GW_trendsout_v2.0.csv, the groundwater water level trend data from both the National Groundwater Monitoring Network and the National Water Information System
GW_confband_out_v2.0.csv, the confidence bands associated with the groundwater water level trend data from both the National Monitoring Network and the National Water Information System A .zip file containing all of the code used to compute these trends along with a README file with information on using the code First posted - Feb 27, 2024 (available from author) Revised - Jan 30, 2025 (version 2.0)

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Created Date April 2, 2024
Metadata Updated Date February 21, 2025

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date April 2, 2024
Metadata Updated Date February 21, 2025
Publisher U.S. Geological Survey
Maintainer
@Id http://datainventory.doi.gov/id/dataset/1966a14e13f29b6ad9382bfb9f5a29c5
Identifier USGS:650b31f8d34e823a02735c0b
Data Last Modified 20250127
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://datainventory.doi.gov/data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 54066803-7ad8-438c-9139-079ebf98d077
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -178.21,17.3087,-65.0,71.35
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 73df2f5fc858adcbafb1b1322e13bca59a38b601b1c15df13d168c957752a3ee
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -178.21, 17.3087, -178.21, 71.35, -65.0, 71.35, -65.0, 17.3087, -178.21, 17.3087}

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