Dredging Operations Technical Support Program. Design and Management of Dredged Material Containment Areas to Improve Hydraulic Performance.
Abstract
This study presents observed residence time distribution data from some 12 DMCAs. These data were collected by injecting Rhodamine WT dye at the inflow point and monitoring dye concentration in the outflow. The resultant time-concentration curve is identical to the residence time distribution during the dyed test. In addition, similar data for chlorine contact chambers, physical models, and waste stabilization ponds found in the literature are also examined. A composite data set from all different sources showed a strong relationship between the ratio of mean residence time to theoretical residence time (theoretical residence time is equal to the pond volume divided by the average flow rate) and the pond length-width ratio. Baffles or spur dikes can be used to increase the effective length-to-width ratio of a given DMCA, thereby increasing the mean residence time without increasing the overall size. The relationship between mean residence time and length-width ratio was incorporated into the DMCA design procedure, and a process for selecting DMCA size, shape, and spar dike layout to achieve minimum cost resulted. The utility of state-of-the-art mathematical hydrodynamic models for stimulating flow through DMCAs is examined in Appendix A. It was found that the mathematical models are capable of reproducing the observed residence time distributions fairly well if model coefficients are arbitrarily adjusted to achieve best fit. However, better field data will be required to develop reliable a priori modeling capability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1987
- Accession Number
- ADA187235
Entities
People
- Donald P. Bach
- Edward L. Thackston
- F. D. Shields Jr.
- Paul R. Schroeder