Development of Baseline Water Quality Stormwater Detention Pond Model for Chesapeake Bay Catchments

Date of Award

Spring 1999

Document Type


Degree Name

Master of Science (MS)


Civil & Environmental Engineering


Environmental Engineering

Committee Director

Jaewan Yoon

Committee Member

A. Osman Akan

Committee Member

David R. Basco

Call Number for Print

Special Collections LD4331.E54 M87


A stormwater detention pond model, EEMD (Environmentally Economic Management Design), was developed using VisualBasic to facilitate the design of extended detention basins. A detention basin is a design such that a site's stormwater runoff would meet certain environmental impact requirements. To ensure these environmental requirements are meet the Commonwealth of Virginia subscribes to the procedures outlined by the Chesapeake Bay Local Assistance Department (CBLAD).

The purpose of the Chesapeake Bay Local Assistance Department (CBLAD) Calculation Procedures is to ensure that the development of constructed areas do not further exacerbate current problems of stormwater-induced eutrophication and downstream flooding. The methodology is based on the post development conditions that will not generate greater peak flows and will result in a 10% overall reduction of total phosphorous. Currently, several wellknown models can develop hydrographs and pollutographs that accurately model the response of a given watershed and stormwater management system to any rainfall event. However, the conventional method of determining pond size to achieve the desired peak flow reduction and pollutant removal is not a deterministic procedure.

A method of quickly and accurately determining the required size of stormwater easements was developed using optimization techniques to evaluate the effectiveness of alternate stormwater collection and treatment systems. Predevelopment conditions are modeled first to

estimate the peak flows and subsequent pollutants generation that can used as a "baseline" for post development plan. EEMD (Environmentally Economic Management Design), a computer application written for this study, designs ponds for peak flow reduction and detention time given the most basic data such as: inflow hydrograph and maximum allowable pond depth. The design can be optimized for either cost minimization or smallest-possible pond size.

Early determination of stormwater easements facilitates the decision-making processes during the planning and development phase of a project. Though EEMD was specifically written to aid the planning process of developments located in the Chesapeake Bay Watershed, its methods are applicable to any pond design where detention time and peak flow reduction are the determining parameters.


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