IR Web Mapping Application

This web map provides assessment summary details for waters identified within the draft 2026 305(b)/303(d) Water Quality Assessment Integrated Report. The Assessment Unit (AU) dataset was created from United States Geological Survey (USGS) National Hydrography Dataset (NHD) high-resolution 1:24,000 data extracted in September 2012. DEQ regional assessment staff assigned previously established assessment unit IDs based on predetermined up- and downstream extents and applicable Water Quality Standards. Some erroneous waters were removed, and a few waters were updated using Virginia Base Mapping Program aerial photography from Virginia Geographic Information Network (VGIN), and recent NHD data, where available. Assessment stations include DEQ and non-DEQ data sources for samples collected within the current 6-year inclusive data window (20190101 - 20241231). Reference layers are included as related tables where possible.