The French Broad River

Includes two sites on the French Broad River

The upstream site on the French Broad River at Banner Farm Road rates below average and the downstream site at Butler Bridge Road rates average. The main differences between the two sites are the higher sediment concentrations at the upstream site and the occasional elevated levels of conductivity and heavy metals at the upstream site. Much of the sediment in the river originates in Transylvania County where median sediment concentrations reach a peak (Figure 12). A likely source of much of the sediment is bank erosion on the river itself as median sediment concentrations for all Transylvania County sites is quite low. Although there are areas along the banks in Henderson County that are also eroding, in general there are more extensive buffer zones along the river than in Transylvania County. Also, although there are many streams contributing large amount of sediment to the river, there are also some large streams like the Mills River that contribute relatively sediment-free water to the system. The Little River, another large, relatively sediment-free stream, flows into the French Broad River between the downstream site in Transylvania County and the upstream site in Henderson County and also helps dilute sediment concentrations in the river.

Turbidity, conductivity, and heavy metals levels are also slightly higher at the upstream site in Henderson County than at the downstream site and also higher here than at the most downstream site on the river in Transylvania County. Contributions from Gash Creek may be a factor. Nutrient concentrations are relatively equal at both sites with greatest contributions in Henderson County coming from Gash Creek before the river reaches the upstream site and from Mud Creek before the river reaches the downstream site. Trend analysis shows nutrient, copper, and conductivity levels increasing over time at the downstream site on the French Broad River.