Conservation of blackwater rivers and streams of the coastal plains of United States: Knowledge and research needs.

Blackwater rivers and streams are a distinct resource type in multiple ecoregions of the United States, including the Coastal Plains. Given the unique nature of blackwaters, they may not be fully protected if using typical water quality standards. Information provided by State agencies was used to identify specific research needs that would directly enhance current assessment approaches. Protection of blackwater rivers and streams would be aided by (1) development of an operational definition; (2) development of a classification framework that distinguishes among blackwater system types; (3) identification of undisturbed or minimally disturbed blackwater systems; (4) identification of stressors that challenge blackwater condition and resilience; and (5) development of criteria that are more suited to the unique conditions of blackwater rivers and streams. Benefits stemming from addressing these research needs may include identification of sites that are unrecognized as impaired and the re-evaluation of sites that may be erroneously listed as impaired when they are not. This would improve reporting by states for Clean Water Act (CWA) Section 305(b) and, for some states, could represent a significant resource savings by reducing the number of sites on CWA Section 303d lists.