HR: 1340h
AN: H53C-1400    [Abstracts]
TI: Quantifying the spatial and temporal distribution of sediment loading to the perimeter of construction sites
AU: * Bogonko, M N
EM: bogonko@rohan.sdsu.edu
AF: State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AU: Farrel, L
EM: lferrell@rohan.sdsu.edu
AF: State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AU: Beighley, R E
EM: beighley@mail.sdsu.edu
AF: State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AU: Walsh, K D
AF: State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AB: Large scale construction projects can dramatically change the drainage pattern of a landscape. During the earthwork phases of construction internal drainage networks are altered even though connections to the existing networks beyond the site boundary must be maintained. These modifications result in large differences in contributing area and sediment loading to specific points along the site perimeter. While most construction projects require stormwater pollution prevention plans to control runoff, these plans often only consider pre- and post- site conditions. Due to significant increases in soil erosion and off-site sediment discharge potential during construction, a better understanding of the sediment loadings throughout the construction process is needed. This study investigates the spatial and temporal distribution of drainage characteristics and sediment loading to the perimeter of construction sites using GIS-based methodologies A case study is presented to illustrate the approach for initial, 25, 50, 75 and final grading. The study site has a land area of 210 ha and is located in southern California. The site has a perimeter length of 3.6 km, and using a 0.6 meter elevation grid, the perimeter consists of 7191 pixels, with each pixel representing one watershed draining to the perimeter. The results show how the distribution of drainages, flow lengths and estimated event sediment yield change over time. The maximum drainage area to site boundary for pre- and post- conditions is 68 and 39 ha, respectively. Predicted sediment yield to the perimeter of the site for pre- and post-grading conditions is 12 and 20 t/ha, respectively. The maximum sediment yield from an individual watershed (i.e., point loading to the perimeter of the site) decreased from 230 to 30 t/ha for pre- and post-grading conditions. Based on the grading schedule, the site is characterized at five time intervals. Preliminary results suggest that quantifying the sediment loading to the site perimeter at only the initial and final stages of grading can underestimate the potential maximum sediment load to the perimeter of the site.
UR: http://spatialhydro.sdsu.edu
DE: 1815 Erosion
DE: 1819 Geographic Information Systems (GIS)
DE: 1862 Sediment transport (4558)
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting