This data includes streams of Arkansas that have been assessed as Impaired Waterbodies and have completed TMDLs (Total Maximum Daily Loads) for the listed pollutant pair(s) (Category 1b). It consists of a subset of the streams from the National Hydrography Dataset (NHD) High Resolution (1:24,000) Waterbody. Category 1b is described as follows: Category 1b is a subcategory within the CWA listing process, specifically for waters that have achieved their water quality standards but still have a TMDL in place for certain pollutants. This might be the case where a TMDL was developed and implemented, leading to water quality improvements that meet the standards, but the TMDL is kept on the record as a protective measure or to ensure continued attainment.