Guidance manual for integrated wet weather flow (WWF) collection and treatment systems for newly urbanized areas (New WWF Systems)

摘要: This research project develop and demonstrated a methodology to guide design engineers in developing appropriate wet weather flow (WWF) drainage systems. Specific aspects of this guidance document address the historically mutually conflicting objectives of providing drainage services at the same time as decreasing stormwater pollutant discharges. Numerous drainage design procedures have been used for more than 100 years in the western world. However, major changes have occurred frequently over this period of time in response to specific problems encountered. Unfortunately, current drainage design procedures, while providing adequate levels of service if correctly implemented, commonly conflict with attempts to reduce stormwater pollutant discharges and associated receiving water problems. Water quality aspects of wet weather flow discharges and associated receiving water problems have only been studied for a relatively short period (a few decades), compared to conventional drainage designs (a few centuries), and few large-scale drainage systems adequately address both of these suitable objectives.This report presents a methodology that incorporates procedures that can be applied to the broad range of conditions that are likely to be encountered in the US to address both drainage and water quality objectives. The methodology builds upon past experiences in drainage design (including some currently not being used in the US) and uses current design tools that are readily available. As an example, it may be appropriate to consider the use of combined sewers and WWF discharge treatment in heavily urbanized areas …