Discharge-displacement calculations for tidal flushing

Occasionally it is necessary to determine displacement/discharge estimates of material introduced into coastal lagoons. The use of sophisticated numerical models may be inappropriate due to cost or time constraints. A technique is presented here to provide relatively quick estimates with a minimum amount of data. An example of the scheme applied to a multi-basin inlet-bay system is given for the application of a phased ebb discharge of material. Based on segmented application of the filling equation, discharge "windows" as a function of tidal characteristics are developed. The windows are constrained to allow substantially all of the material discharged to exit the system during a single tidal cycle.