4.5 River Basins
4.5.9.4 Threats Affecting Aquatic Species Nonpoint source pollution and altered hydrologic regimes are primary impacts on native aquatic communities and their habitats in the Hiwassee basin. Human population growth, and associated residential and commercial development, is one of the most important issues in the basin. Development on steep slopes, increased impervious surfaces, contrib- ute to increased erosion and sedimentation, as well as increased wastewater and runof of contaminants, which negatively impacts water quality, hydrology, and aquatic habitat (NCDWQ 2012b) . Development is likely to increase substantially in the basin in the coming years. Including the seven impoundments regulated under FERC licensing or operated by TVA in the basin, an NCDENR dam inventory (NCDEMLR 2014) indicates there are at least 52 impoundments in the basin. Fifty-seven miles of historically free-fowing riverine habitats are now either seasonally or permanently fooded by Chatuge, Mission, Hiwassee, and Appalachia dams and reservoirs, or are indirectly afected by impoundment. Te unim- pounded reaches of the Nottely and Hiwassee rivers, downstream from dams, are afected by coldwater releases, altered hydrologic regimes, and periodic low levels of DO due to hypolimnetic and peaking power production releases from Chatuge and Nottely dams. Impoundment and thermal alteration may further afect native species by fragmenting available suitable habitat and isolating historically contiguous populations in tributaries. Te NCDWR also monitors state waters to determine if they are supporting their use clas- sifcation(s) and assigned use-support ratings. Te NCDWR reports Lake Chatuge has been consistently oligotrophic (ofering little to sustain life) since monitoring frst began (2012b) and ecological health has been rated primarily as either poor or at the low end of the fair range in most years (TVA n.d.) . Periodic higher ecology health ratings have been associated with improved chlorophyll levels, higher levels of DO, timing and amount of rainfall, and changes to runof and contaminants in sediment (TVA n.d.) . Te Hiwassee River Watershed Coalition and TVA developed the Lake Chatuge Watershed Action Plan (HRWC 2007) to serve as a restoration guide for returning the lake to good ecological health. Nonnative species also pose potential threats to native aquatic species in the Hiwassee River Basin. Te Blueback Herring, Asian Clam, Striped Bass, Snail Bullhead, Rainbow Trout, Brown Trout, and Rusty Crayfsh are established in the basin. Blueback Herring appear to be having an impact on game species (i.e., Walleye) in the Hiwassee Reservoir and Hiwassee River, but impacts to nongame species are unknown at present. Specifc impacts from Asian Clam and introduced game fshes are also unclear. Other potential problems are indirect efects from invasive plant species and exotic pathogens that can signifcantly alter riparian vegetation (e.g., Japanese Knotweed, Hemlock Wooly Adelgid).
554
2015 NC Wildlife Action Plan
Made with FlippingBook - professional solution for displaying marketing and sales documents online