1996) and a wide variety of urban stormwater BMPs (CRC for Catchment Hydrology

2005). The KC* model uses a removal rate model with a background concentration (C*).

Removal is a function of the initial concentration (C,,), C* the overall rate constant, kv,

and the hydraulic residence time (HRT), td. The KC* equation is shown in Equation 4-4.

The pollutant is removed more rapidly at first and then at a decreasing rate as HRT

increases. Two-parameter calibration should be used for this model, where kv and C* are

calibrated simultaneously.

Cot = C* + (C,, C)e k_-td (4-4)

Model Rationale

 The University of Florida Water Quality Design Tool (UF WQDT) was intended

from the outset to be a simple spreadsheet model used to predict the behavior of TP in the

EAASR. The storage-release framework described in Lee et al. (2005) was to be used to

provide an optimal design, which included water quality considerations. It was decided

that a basic mass balance and uptake rate model would provide a good representation of

TP behavior. Initially modeling was expected to occur at three levels; steady-state

simulation of the long-term average, frequency analysis, and daily time series analysis.

However, as the design and planning challenges became evident the scope of the model

was altered to best suit the needs of the project and the tight time schedule.

 Steady-state simulation of long-term averages was deemed the most appropriate

modeling level for the dynamic conditions associated with the design of the EAASR. A

steady-state analysis can provide important insights and comparisons to design scenarios.

The simple mass-balance model is easily adapted for new configurations and scenarios,

while the steady-state nature allows for very fast run times. SFWMM updates and small