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Hydrographic and Impairment Statistics Database: ILMI

Metadata Updated: November 25, 2025

Hydrographic and Impairment Statistics (HIS) is a National Park Service (NPS) Water Resources Division (WRD) project established to track certain goals created in response to the Government Performance and Results Act of 1993 (GPRA). One water resources management goal established by the Department of the Interior under GRPA requires NPS to track the percent of its managed surface waters that are meeting Clean Water Act (CWA) water quality standards. This goal requires an accurate inventory that spatially quantifies the surface water hydrography that each bureau manages and a procedure to determine and track which waterbodies are or are not meeting water quality standards as outlined by Section 303(d) of the CWA. This project helps meet this DOI GRPA goal by inventorying and monitoring in a geographic information system for the NPS: (1) CWA 303(d) quality impaired waters and causes; and (2) hydrographic statistics based on the United States Geological Survey (USGS) National Hydrography Dataset (NHD). Hydrographic and 303(d) impairment statistics were evaluated based on a combination of 1:24,000 (NHD) and finer scale data (frequently provided by state GIS layers).

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.

Downloads & Resources

Dates

Metadata Created Date September 12, 2025
Metadata Updated Date November 25, 2025

Metadata Source

Harvested from DOI NPS DCAT-US

Additional Metadata

Resource Type Dataset
Metadata Created Date September 12, 2025
Metadata Updated Date November 25, 2025
Publisher National Park Service
Maintainer
Identifier http://datainventory.doi.gov/id/dataset/nps-datastore-2244409
Data First Published 2017-09-25T00:00:00Z
Data Last Modified 2017-09-25T00:00:00Z
Category geospatial
Public Access Level public
Bureau Code 010:24
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://ddi.doi.gov/nps-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 58753115-642e-446f-9560-7583ba5ffdf2
Harvest Source Id d917c1a9-26b7-43ea-b8c5-c77ec750a850
Harvest Source Title DOI NPS DCAT-US
Homepage URL https://irma.nps.gov/DataStore/Reference/Profile/2244409
Metadata Type geospatial
Program Code 010:119, 010:118
Source Datajson Identifier True
Source Hash 9468102d50565ac2d20e68d9b588858e80e9a70454eceb20f038507187216511
Source Schema Version 1.1

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