Making Watershed Data Easily Accessible for All – New Data and Tools in the StreamCat API

The U.S. EPA maintains an application programming interface (API) and underlying database that provides access to StreamCat and LakeCat datasets. StreamCat and LakeCat are extensive datasets of landscape metrics for the local drainage areas (catchments) and full watersheds of ~2.65 million stream segments and ~400,000 lakes within the conterminous United States (U.S.) based on the National Hydrography Dataset Plus Version 2 (NHDPlusV2). The StreamCat and LakeCat data reduce the specialized geospatial expertise needed by researchers and managers to acquire landscape information for both catchments (i.e., the nearby landscape flowing directly into streams) and full upstream watersheds of specific stream reaches, as well as landscape basins for lake features. To enhance data access and usability, EPA scientists developed the StreamCat API, as well as an R package (StreamCatTools) that leverages the API. These developments facilitate easier and simpler access to the data for the broad community of federal, local, state, academic, and non-governmental organizations that use StreamCat data. Since the initial development of the API, LakeCat data were added to the database and we are currently adding hundreds of new metrics from the EPA National Nutrient Inventory program. Inclusion of the National Nutrient Inventory will facilitate the access of important information on nutrient loads to watersheds for any stream reach or lake within the NHDPlusV2.  In this talk we will highlight these new data as well as new functionality, such as access to watersheds for all lakes in LakeCat as spatial features in the StreamCatTools R package and functionality to easily meld this rich set of landscape metrics with other water quality data for visualization, analysis, and modelling.

Impact/Purpose

This talk highlights recent developments and tools that facilitate the use of StreamCat and LakeCat data, two datasets of hundreds of landscape metrics for all rivers and streams and lake features represented in the National Hydrography Plus V2 dataset.  These data have been used extensively for research internally at the EPA, by states and tribes as well as academics and non-profit institutions, and the supporting papers have been cited in well over one hudred peer-reviewed publications.  We will focus on how we continue to make this fundamental data easily accessible and up to date in this talk.

Citation

Weber, M., R. Hill, A. Brookes, AND T. Hudson. Making Watershed Data Easily Accessible for All – New Data and Tools in the StreamCat API. National Monitoring Conference, Green Bay, WI, March 10 - 14, 2025.