Model Calibration for Sediment Pond Discharge

The author's two-dimensional model for unsteady sediment discharge at a pond outlet was developed using the finite element method. The model simulates depth-averaged flow velocity in the pond and the depth-averaged suspended sediment moving from the pond inlet to the outlet. Modeling results can provide information regarding the depth-averaged suspended sediment distribution in the pond and the unsteady sediment discharge at the outlet. The model contains pond hydraulic parameters and sediment parameters. These parameters, however, need to be calibrated with field data. Once calibrated, the model can be verified as a useful sediment pond design tool that could benefit engineers who prepare erosion and sedimentation control plans for construction sites. A research group at Pennsylvania State University has performed numerous field experiments that have studied and continue to study sediment pond discharge. Some of the published data are adopted to calibrate the parameters. In this paper, the data quoted from Pennsylvania State University is designated as PSU data. Other data, quoted from a published Federal Highway Administration report, is designated as FHWA data. The FHWA data is used to develop a formula that defines the suspended sediment at the pond inlet after the influent sediment ceases within the pond inflow. This formula, defined and fitted to the FHWA data, is used for determining the boundary condition at the pond inlet for the model after the pond inflow approaches zero. The model calibration shows that more data is needed to quantify and detail the range for each parameter. Preliminary numerical values for the parameters have been found and can be important to engineers for sediment pond design. Using the field data without knowing the point of field sampling, however, could affect the model's calibration. Therefore, further investigation is required to define the range of numerical values that most accurately represent a pond's condition in the field.