EnviroAtlas - Watershed Index Online (WSIO) Indicator Data Tables - Impaired Waters by 12-Digit HUC for the Conterminous United States
This EnviroAtlas dataset contains information about 303(d) impairments by 12-digit HUC. It uses data that was originally compiled for the Watershed Index Online (WSIO) Version 2.4, released August 31, 2022. 

This dataset was produced by the US EPA to support research and online mapping activities related to …