HR: 1400h
AN: H33B-03    [Abstracts]
TI: Evaluating Effects of Land-use Change on Stream Hydrology and Water Quality in the Reedy River Watershed
AU: * Santikari, V P
EM: vsantik@clemson.edu
AF: Department of Environmental Engineering & Earth Sciences, 340 Brackett Hall Clemson University, Clemson, SC 29634-0905, United States
AU: Murdoch, L C
EM: lmurdoc@clemson.edu
AF: Department of Environmental Engineering & Earth Sciences, 340 Brackett Hall Clemson University, Clemson, SC 29634-0905, United States
AU: Schlautman, M A
EM: mschlau@clemson.edu
AF: Department of Environmental Engineering & Earth Sciences, 340 Brackett Hall Clemson University, Clemson, SC 29634-0905, United States
AB: Conversion of land cover from forested to urban is a major cause of nonpoint source pollution of the surface waters. During active land conversion/development, suspended sediment eroded from exposed soils often is the primary source of surface water degradation. Despite the use of Best Management Practices (BMPs), the overall protective goals of erosion prevention and sediment control regulations are not always achieved. The objective of this study is to understand and predict the impact of construction activities on stream hydrology and water quality and to assess the overall, collective effectiveness of BMPs that were implemented. Hydrologic, sediment, and nutrient data were collected from several streams that are tributaries of the Reedy River, South Carolina. These streams drain catchments (~1 km2) with varying degrees of active disturbance due to housing construction. Some were highly disturbed, others moderately disturbed, while others served as relatively undisturbed references. Stationary and handheld instruments that use Doppler technology were employed to measure the flowrate in these streams. Upon comparing measurements from these two types of instruments, it has been observed that the stationary instrument consistently over-estimated flowrates because it sampled only a small, faster moving portion of the stream. Therefore, one empirical and several physically based procedures (conveyance-slope method, and rectangular channel approximation method) were developed to correct the time series of flow made with the stationary instrument. Sediment and nutrient concentrations in the outflows from the disturbed catchments are compared with those of the undisturbed catchments to quantify the extent of disturbance. Peak flows from disturbed catchments were up to two orders of magnitude greater, and sediment yields were up to three orders of magnitude greater than those from the reference catchments. Several metal concentrations (e.g. Fe, Mn, Al, Mg, and K) follow a similar trend and are strongly correlated with the sediment. Using the formulation of the Universal Soil Loss Equation, the product of cover-management factor (C) and support practice factor (P) is calculated for each land-use type. Since all other factors in the USLE (R, K, L, and S) have same values across the catchments at any given time, the product (PC) quantifies the extent of disturbance in terms of sediment yield. Preliminary relative values of this product (PC) for agricultural land = 2.4, forest land = 1.0, fully developed urban land = 0.9, and construction site = 150.
DE: 1804 Catchment
DE: 1847 Modeling
DE: 1850 Overland flow
DE: 1860 Streamflow
SC: Hydrology [H]
MN: 2009 Joint Assembly