Level III: Receiving Water Quality Modeling for Urban Stormwater Management

摘要

A simplified continuous receiving water quality model has been developed as a planning guide to permit preliminary screening of areawide wastewater treatment strategies. The model simulates the hypothetical response of the stream or tidal river system to the separate and combined effects of waste inputs from: (1) upstream sources, (2) dry weather urban sources, and (3) wet weather urban sources. The total hours of runoff-producing rainfall throughout a year are separated into storm events by defining a minimum interevent time. For a given storm event, the runoff and pollutant loads are summed and critical dissolved oxygen concentrations are estimated as a function of several hydrodynamic and biochemical parameters. Model output includes the downstream dissolved oxygen sag curves computed per each event, and the dissolved oxygen profile computed at a user-specified location downstream for all simulated events. An application to the Des Moines River at Des Moines, Iowa, is presented.