Research needs in urban wet weather flows

The results of a national assessment of research needs in urban wet weather flow management are presented. Three interrelated categories of urban wet weather flow management are discussed: combined sewer overflows, sanitary sewer overflows, and urban stormwater discharges. The initial compilation of wet weather flow research needs totaled 154 research projects, which was later reduced to 69 higher-priority research projects for which detailed literature reviews were compiled. From this group, 26 topics were selected as priority research topics. Within this paper, the results of the assessment were organized into the following ten categories: (1) sources and monitoring; (2) receiving water effects; (3) other effects; (4) management; (5) models and decision support systems; (6) watershed management linkages; (7) regulatory policies and financial aspects; (8) source controls; (9) collection system controls; and (10) storage/treatment systems. A summary of the authors' views on research needs within each category is provided. An expenditure of an estimated $20 to $40 million per year in the U.S. is needed to address the identified research needs.