ABSTRACT
The traditional design of storm drainage systems has been to collect and convey storm runoff as rapidly as possible to a suitable location, where it can be discharged. As areas urbanize, this type of design may result in major drainage and flooding problems downstream. The impacts of urban development include faster and higher peaks, more flow volume, higher velocities, higher temperatures, lower base flows during nonstorm conditions, and greater levels of pollution. This chapter deals with flood flow peak reduction, timing strategies, and design. A later chapter will address stormwater quality (Chapter 15). Because municipalities use different design storms for detention design, examples are given in this chapter based on different design storm events (e.g., 2-year, 10-year, 25year, and 100-year). The principles and procedures are the same for any design storm that is selected.
