Many parts of the southeastern US are in the middle of an extreme drought that not only threatens our agricultural productivity, but also may lead to forest fires that have other cascading events. One such event is the impact on drinking water quality. Greenville, SC obtains the bulk of its drinking water from a well-protected reservoir that is situated in the middle of a forest that is currently heavily damaged by ongoing forest fires that just got under control within the past week. With the ensuing seasonal rains, much of the burned material will enter the streams that supply water to this large, metropolitan city. Our aims in this project are to access the changes that the forest fire has on the hydrology and water quality of this important reservoir. We will compare hydrological, biological and chemical differences between streams impacted by fire and those that have not been impacted to evaluate if these extreme events affect the quality of our drinking water. We will combine new hydrological models and next generation molecular tools with standard chemical measurements to investigate these differences. An engineering graduate student that is helping to develop the hydrological model will also be cross-trained in these latest microbiological and statistical techniques. Our assessment will be an important step in understanding what impacts forest fires may have on water quality in other areas of the US. The objective of this project is to collect perishable water quality related data to determine how the current combination of climate extremes such as droughts and subsequent wildfire events affect a pristine watershed in South Carolina in terms of its hydrology, water quality, and microbial community composition and structure. Specifically, we will address the following: a) How does the water quality change within a watershed following fire? How much water quality change is controlled by change in watershed conditions (altered landscape and changing hydrology) vs changes in stream internal processes? and b) We will evaluate the consequences of drought - wildfire regime specifically after the destruction of the vegetation cover and the subsequent alteration of spatial soil properties (e.g., infiltration) and geomorphic features on runoff and sediment loads in a pristine watershed based on the pre-fire and the post-fire conditions. We will assess the influence of wildfires on stream water quality, for example, dissolved oxygen, nitrate, phosphate, heavy metals and ammonium; taxon richness (alpha diversity) and the structure and composition of microbial communities. We will utilize next-generation sequencing to assess the microbial communities and statistically compare differences in water quality as assessed by these molecular and chemical assays to streams not impacted by forest fires. With these experiments we hope to quantify the major controls on post-fire water quality as well as the internal stream processes that mitigate stream water quality. These data will enable stream water quality recovery times to be better characterized and will directly impact how the post-fire watershed should be managed as a public water supply. This research will inform stakeholders (e.g., Greenville water system) about the possible impacts of wildfire on water quality and take necessary steps such as green technology to help mitigate any debris run-off and/or any stream siltation from the burned areas of the watershed. These research findings can be applied to other areas of the U.S. due to current and expected future combinations of drought and wildfire events.
