This study characterized conditions of three forested watersheds, examining the effects of spatial scaling on outflow and runoff behavior. It also expanded the existing database on hydrology of low-gradient forested watersheds like those in the coastal plain of the southeastern United States.
Stream flow in the larger Turkey Creek watershed, covering about 12,800 acres, was comprised of about 47% groundwater discharge. Two small first-order watersheds showed greater runoff moving relatively quickly through the system. Two smaller watersheds, 520 acres and 300 acres, had averages of 38% and 33%, respectively, of stream flow comprised of groundwater discharge. Both small watersheds had a larger proportion of low-permeability soils compared to the soil makeup in the Turkey Creek watershed, so the difference in runoff behavior cannot be solely attributed to the size of the watershed. It should be noted that most land development projects are relatively small in area, on scale with the two small watersheds studied for this project. Those results may be most useful to predict runoff changes as development in the southeastern U.S. coastal plain continues to encroach into forested areas.
These results are useful for scientists who need direct measurements of watershed conditions for forecasting future conditions, either in natural systems subject to changes in weather patterns or due to extreme events, or for landscapes that have or may soon change due to land development in support of increasing populations. Low-impact development practices have been modeled and tested in certain settings, and these ecological engineering approaches may serve as useful proxies of natural processes to reduce the negative impacts of stormwater runoff.
Research Results
Callahan, Tim, Peter Stone, and Devendra Amatya. “Coastal Forests and Groundwater: Using Case Studies to Understand the Effects of Drivers and Stressors for Resource Management,” Sustainability, Vol. 9, Issue 3, 2017