Hydroacoustic and spatial analysis of sediment fluxes and accumulation rates in two Virginia reservoirs, USA

• Published in: Environmental science and pollution research international 2015-06, Vol.22 (11), p.8659-8671
• Main Authors: Clark, E. V, Odhiambo, B. K, Yoon, S, Pilati, L
• Format: Article
• Language: English
• Subjects: Accumulation; Acoustics; anthropogenic activities; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Basin geometry; basins; Colluvial soils; Creeks & streams; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Erosion rates; Geologic Sediments - analysis; human development; hydroacoustics; industrial sites; Lakes; Lakes - analysis; Land use; Models, Theoretical; piedmont; Research Article; Reservoir capacity; Reservoirs; Revised Universal Soil Loss Equation; Sedimentation & deposition; Sediments; Soil; Soil erosion; Spatial Analysis; streams; Studies; surveys; Virginia; Waste Water Technology; Water Management; Water Pollution Control; Water quality; Water supply; Water Supply - analysis; Watershed management; Watersheds
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-014-4050-x

Watershed sediment fluxes and reservoir sediment accumulation rates were analyzed in two contrasting reservoir systems in central and western Virginia. Lake Pelham, located in the Piedmont geologic province, is a human-impacted reservoir with a watershed dominated by agricultural, residential and industrial land uses. Conversely, Lake Moomaw has a largely undeveloped watershed characterized by very steep slopes and forested land use located in the Valley and Ridge province. The Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratios (SDRs) were used to estimate soil losses in the two watersheds. Bathymetric and sediment accumulation surveys of the two reservoirs were also conducted using a multi-frequency hydroacoustic surveying system. The RUSLE/SDR erosion model estimates 2150 kg ha⁻¹ year⁻¹for Lake Pelham and 2720 kg ha⁻¹ year⁻¹for Lake Moomaw, a 410 and 13 % increase from assumed pristine (100 % forested) land use for the respective basins. Mean sediment accumulation rates of 1.51 and 0.60 cm year⁻¹were estimated from the hydroacoustic survey of Lake Pelham and Lake Moomaw, respectively. Overall, Lake Moomaw has relatively low sediment accumulation rates; however, the reservoir is vulnerable to increases in sediment fluxes with further human development due to the steep slopes and highly erodible colluvial soils that characterize the basin. Higher erosion and sediment accumulation rates in Lake Pelham are most likely reflecting the impact of human development on sedimentation processes, where the loss of vegetal buffers and increase in impervious surfaces exacerbates both the surficial soil losses as well as intrinsic stream sediment production leading to the current annual reservoir capacity loss of 0.4 %.