Surface Water - Alabama Department of Environmental Management

Cahaba River (0315-0202)
Sub-Watershed: Cahaba River NRCS Sub-Watershed Number 170
Landuse: The Cahaba River sub-watershed drains 78 mi 2 in Perry and Dallas Counties.
Land cover was mainly forest and pasture (Appendix A). Within this sub-watershed, the
Cahaba River is designated as an Outstanding Alabama Water for its entire length (ADEM
2003e). A 4.5 mile segment of Dry Creek is impaired by pathogens from agricultural
sources (Appendix C-1). ADEM’s TMDL for this polutant was approved during 2003and
implementation is pending. Two current construction/stormwater authorizations, one
mining, and 2 semi-public/private NPDES permits have been issued in the sub-watershed
(Appendix B).
Percent land cover estimated by local SWCD (Appendix A, ASWCC 1998)
Forest Row crop Pasture Mining Urban Open Water Other
65% 3% 29% 0% 2% 1% 1%
NPS impairment potential: The Cahaba River was identified as a NPS priority subwatershed
in 1996 (O’Neil and Shepard 1997). Based on the 1998 SWCD sub-watershed
assessments, the main NPS concerns were aquaculture, pasture runoff, and septic tank
failure (Appendix D). Cahaba River was given 2 nd and 4 th priority sub-watershed ratings
by the Perry and Dallas County SWCDs, respectively. Resource concerns included
excessive erosion of cropland and roads, overgrazed pastures, access of livestock to
streams, and bacteria in surface waters (Appendix I).
Ratings for each NPS category based on values estimated during the SWCD sub-watershed assessment.
Category
Overall
Potential
Animal
husbandry
Aquaculture
Row
crop
Pasture Mining Forestry Sediment
Value 11 0.12 AU/ac 0.60% 3% 29% 0% 19% 3.6 tons/ac/yr
NPS Potential L L M L M L L L
Appendix D H H A A A I I
Assessments: Childers Creek and Dry Creek were assessed during the 2002 NPS screening
assessment of the BWC Basin Group (Appendix F). These sites were previously assessed
by GSA during the 1996 NPS assessment of the Lower Cahaba River Basin (Appendix E,
Shepard and O’Neil 1997). The Cahaba River has also been intensively monitored in
conjunction with ADEM’s Reservoir Monitoring Program (Appendix E).
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