Principal Investigator: Terry W. Sturm (Georgia Tech)
Sponsor: GWRI
Start Date: 1991-04-01; Completion Date: 1992-03-31;
Keywords: Erosion, Sediment transport, Urban runoff, Settling basins, Design criteria, Urbanization
Description:
This research has focused on an evaluation of current design criteria for meeting an effluent turbidity limit in runoff from construction sites and landfills in Georgia. The research has been completed in two-phases. In Phase I, field data collected by Georgia EPD were analyzed, and the effectiveness of sediment basins in reducing turbidity was studied using numerical data generated by a computer simulation model. In Phase II, the numerical model was used to investigate the effect of changing various sediment basin design criteria, and a new sediment basin design procedure was developed. Both the field data and the numerical simulation results from Phase I showed that sediment basins can be very effective in reducing suspended sediment in runoff, but they cannot meet the turbidity standard in all cases without additional erosion control measures. In Phase II of the research, it was found that the major factor affecting sediment basin performance is soil type followed by basin surface area. The value of erosion control measures used in combination with sediment basins was demonstrated. The proposed design criteria include a detention storage based on the runoff volume from frequent storms; a minimum sediment basin surface area which is a function of soil grain size; a minimum level of erosion control; and a comparison of peak outflow sediment and water discharges with those from the undisturbed watershed. This approach provides a uniform and rational design basis for optimizing sediment basin design to meet the turbidity standard.