Surface Water - Alabama Department of Environmental Management

Cahaba River (0315-0202)
Sub-watershed: Cahaba River NRCS Sub-Watershed Number 150
Landuse: The Cahaba River sub-watershed drains 125 mi 2 in Perry and Dallas Counties.
Land cover was mainly forest mixed with some pasture and crop lands. The entire length
of the Cahaba River in this sub-watershed is designated as an Outstanding Alabama Water
(ADEM 2003e). One municipal NPDES permit has 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% 10% 20% 0% 5% 0% 0%
NPS impairment potential: Cahaba River was identified as a NPS priority sub-watershed
in 1996 (O’Neil and Shepard 1997). GSA found the chemical/physical, habitat, and
biological conditions of the tributary, Rice Creek, to be impaired by nonpoint runoff from
the community of Marion, discharge from a WWTP, excessive sediment transport,
excessive nutrients, and high bacteria concentrations.
Based on information from the 1998 SWCD sub-watershed assessments, the main NPS
concerns in the Cahaba River sub-watershed were runoff from crops, pastures, and forestry
(Appendix D). Cahaba River was given a 3 rd priority sub-watershed rating by the local
SWCD for resource concerns including excessive erosion of cropland and roads and
roadbanks, 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 13 0.05 AU/ac 0.00% 10% 20% 0% 28% 1.0 ton/ac/yr
NPS Potential L L L M M L M L
Appendix D H H A A A I I
Assessments: One sampling location was assessed duringADEM’s2002 NPS screening
assessment of the BWC Basin Group (Appendix F). Waters Creek was reassessed at a
sampling reach established in 1996 by GSA (Appendix E).
Assessment stations located within the sub-watershed. Descriptions provided in Appendix E-1.
Station Assessment Type Date Location Area
(mi 2 )
WAT-1
Chemical, Habitat,
Biological
Classification
2002 Waters Cr. at AL Hwy 14 15 S
Waters Creek: Located in the Fall Line Hills (65i) subecoregion, Waters Creek at WAT-1
was characterized by small sand and gravel riffles (Appendix J). Habitat quality was
70