DOI: 10.5066/p9fisyxq
title: “ChesBay 24k – HU": Human Related Data Summaries for the Chesapeake Bay Watershed Within NHD Plus HR catchments (ver. 3.0, August 2025)

description: These tabular data are the summarization of human related variables within catchments of the Chesapeake Bay watershed at the 1:24,000 scale using the xstrm methodology. Variables being counted as human related include agriculture, barriers, road density, pesticide, and road/stream crossing data. Outputs include tabular comma-separated values files (CSVs), and parquet formatted files for the local catchment and network summaries linked to the National Hydrography Dataset Plus High-Resolution (NHDPlus HR) catchments by NHDPlus ID. Local catchments are defined as the single catchment within which the data are summarized. Network summaries are summaries for each of the local catchments and their respective network-connected upstream or downstream catchments for select variables. The summarized data tables are structured as a single column representing the catchment id values (ie. NHDPlus ID) and the remaining columns consisting of the summarized variables. 

Additionally, for a full description of the variables included within these summaries see xstrm_nhdhr_human_chesapeake_baywide_datadictionary.csv in the attached files.

The xstrm local summary methodology takes either raster or point data as input then summarizes those data by "zones", in this case the NHDPlus HR catchments. The network summaries then take the results from the local summaries and calculates the desired network summary statistic for the local catchment and its respective upstream or downstream catchments.

As a note concerning use of these data, any rasters summarized within this process only had their cells included within a catchment if the center of the raster cell fell within the catchment boundary. However, the resolution of the input raster data for these summaries was considered to provide completely adequate coverage of the summary catchments using this option. If a confirmed complete coverage of a catchment is desired (even if a raster cell only is minimally included within the catchment) then it is recommended to rerun the xstrm summary process with the "All Touched" option set to “True”.

These data were updated in September 2024, March 2025, and August 2025. Some changes during these revisions include the removal of several variables unnecessary to the use of the data summaries, correction of incorrectly calculated area variables and all dependent variables, and the addition of several new variables. For a full list of changes see, xstrm_nhdhr_human_chesapeake_baywide_versionhistory.txt

Further information on the Xstrm summary process can be found at the Xstrm software release pages:
Xstrm: Wieferich, D.J., Williams, B., Falgout, J.T., Foks, N.L. 2021. xstrm. U.S. Geological Survey software release. https://doi.org/10.5066/P9P8P7Z0.
Xstrm Local: Wieferich, D.J., Gressler B., Krause K., Wieczorek M., McDonald, S. 2022. xstrm_local Version-1.1.0. U.S. Geological Survey software release. https://doi.org/10.5066/P98BOGI9.

First release:  August 2023
Revised: September 2024 (ver. 2.0)
Revised: March 2025 (ver. 2.1)
Revised: August 2025 (ver. 3.0)