James P. Heaney

Costs of Urban Stormwater Control

This paper presents information on the cost of stormwater pollution control facilities in urban areas, including collection, control, and treatment systems. Information on prior cost studies of control technologies and cost estimating models used in these studies was collected, reviewed, and evaluated. The collection phase involved identifying, screening, and consolidating publications associated with capital costs of stormwater conveyance systems and control technologies. The resulting data were evaluated to develop a critical review of costs for urban stormwater control technologies, including identification of cost information gaps and research needs.

Micro-scale Modeling of Low Impact Development

Low Impact Development (LID) is an innovative micro-scale runoff control strategy for WWF management issues. This technology is based on a combined strategy of conservation to reduce hydrologic impacts and the incorporation of distributed micro-scale Best Management Practices (BMPs) throughout the subcatchment. This site-based approach has a goal of maintaining the pre-development hydrologic regime of the project site. Because this is a volume-based approach to management of runoff, there is great potential to reduce the runoff volume, sediment loads, and floatables that can reach receiving waters. In order to fully understand the effects of reduced runoff volume and timing, as well as the full implementation of this technology within the catchment, modifications to existing models and new models must be developed. This paper will explore the potential and limitations of existing models to evaluate the effectiveness of this design approach.

Risk-Based Design of a Sanitary Sewer Overflow Control Plan

Detailed flow and rainfall measurements, accompanied by long-term simulation, were used to identify the inflow and infiltration response characteristics of the sanitary sewer collection system in Vallejo CA. This response has produced sanitary sewer overflows on numerous occasions throughout various locations in the collection system. A mix of collection system rehabilitation, capacity upgrades, storage and increased treatment capacity may be used to control future wet-weather flows to a regulatory standard. A major limitation to optimizing the design of these wet-weather controls is a relatively high uncertainty regarding the effectiveness of collection system rehabilitation to control wet-weather flows. The ability of collection system rehabilitation activities to control wet-weather flows will in turn affect the performance of all downstream controls, including conveyance, storage and treatment. If rehabilitation effectiveness is over-estimated, overall control performance will not meet design standards, and if underestimated, significant overexpenditure of resources is possible. A risk-based approach was used to identify the importance of rehabilitation effectiveness on the overall design. Probability density functions of wet-weather pollutant control for storage, treatment and rehabilitation were derived from direct observations and used to estimate the overall reliability of various mixes of design alternatives. Based on this analysis, a concentrated smallscale rehabilitation project was used to reduce the uncertainty associated with estimating the performance of rehabilitation for sanitary sewer overflow (SSO) control. The results of the rehabilitation test were used to refine the risk-based design of the SSO control plan. Actual rehabilitation costs were used to estimate a costeffectiveness relationship for this specific collection system. A process model was used to link the performance and costs of storage, treatment, conveyance and rehabilitation. This design model was formulated as a nonlinear optimization problem, and a generalized reduced gradient search algorithm was used to find the best mix of alternatives to meet various regulatory goals in a cost-effective manner. Various levels of cost and risk were then generated with this model for meeting performance expectations, aiding the design team by concentrating their efforts on an array of non-dominated solutions.

Decentralized and Low Impact Development (LID) Controls for Combined Sewer Overflow Management

This paper presents the findings of several critical studies that the project team is conducting to evaluate the feasibility and long-term viability of using decentralized controls for CSO management. The project team has developed a substantial set of analysis tools for use in the development of modeling and monitoring programs, including proposed classification schemes for decentralized controls and descriptions of unit processes. The study also provides guidance on determining the feasibility and effectiveness of controls, including an analysis of optimization, cost, and techniques to manage runoff volume, peak discharge rate, and water quality. Regional case studies on strategies, costs, and maintenance practices are presented.

On Integrating Continous Simulation and Statistical Methods for Evaluating Urban Stormwater Systems

The purpose of this chapter is to discuss various approaches for estimating the pollutant removal by urban stormwater detention systems. After a brief descript…