Water Quality Data

Since the early 1970s, primarily as the result of the Clean Water Act of 1972, the reduction in sewage and industrial effluents, known as point-source pollution, has greatly improved water quality in the Saluda and Reedy River basins. By the mid-1980s, wastewater treatment plants were substantially improved and permit limits tightened, such that significantly reduced concentrations and masses of nutrients and other pollutants were being discharged. The levels of nutrients evident in the streams dropped dramatically in response to these management actions, as illustrated by these charts.

As a result, water quality in our rivers and streams has improved significantly over the past several decades. Less nitrogen and phosphorous in the water meant less algal growth, which translated into more dissolved oxygen in the water as this graph demonstrates. (Algae growth is stimulated by nutrient enrichment, and as algae die and decay their decomposition can consume oxygen in the water column, potentially leading to oxygen depletion.) Dissolved oxygen levels need to remain above five milligrams per liter of water for most fish species to thrive. As the graph shows, the reduction in nutrients over the last few decades correlates directly with an increase in levels dissolved oxygen.

Long-Term Dissolved Oxygen Trends in the Major Saluda-Reedy Watershed Rivers

While the general trends have been improving across the region, challeneges still remain. Today in the Upstate, the volume of soil eroded from building sites or agricultural fields during heavy rains is many hundreds of times the volume that would erode from a natural, undisturbed landscape. This sediment overload is choking our waterways and severely degrading water quality, and is the number one threat to our rivers and lakes, as these graphs of sediment load in the Saluda and Reedy illustrate.

Almost as important as sedimet is the issue of flooding. The rapid rate of development throughout the Upstate has caused an increase in the proportion of impervious cover across the landscape. As the proportion of impervious cover increases, more water runs off and less soaks into the ground when it rains. In urban settings, the run off is often referred to as stormwater and this graph illustrates the dramatic differences in stormwater runoff generated in a undeveloped subwatershed (Knight Creek) as compared with a highly developed one (Lost Creek). Both subwatersheds are in Greenville County.