Guide for Municipal Wet Weather Strategies: Overview of How the Collection System Fits into a Holistic Approach

Successful implementation of a regulatory program depends on good planning and wise decision making in selecting the most effective technologies, best practices and other standards used by the municipal wastewater community. The WEF “Guide for Municipal Wet Weather Strategies” (2013), an updated version of the 2006 WEF “Guide to Managing Peak Wet Weather Flows in Municipal Wastewater Collection and Treatment Systems”, provides an approach for the analysis of collection and treatment of wastewater flows during wet weather events which can be used to build support for real-world solutions that effectively use resources to improve water quality and overall system performance.Municipal utilities need to provide significant improvements on how they manage wet weather related flows in their wastewater collection system as the result of increased regulatory requirements, public pressures, and aging infrastructure. Wet weather flows in combined sewer systems or separate systems, in many cases, exceed the original sewer hydraulic design capacity. The overall approach necessary to identify, evaluate, and eventually select the “best” combination of wet weather improvements for a particular collection system is one that is unique to each municipality.This paper will provide an overview of sustainable collection system strategies for effective wet weather flow management in order to encourage engineers, planners, and designers developing wet weather improvement plans to take a holistic approach to wet weather facility planning that includes all system components (collection system, treatment facilities, and private service lines & connections). Principles for collection system management provided in the July 2010 WEF/NACWA “Core Attributes to an Effectively Managed Wastewater Collection Systems” and strategies provided in the 2013 WEF “Guide for Municipal Wet Weather Strategies” are highlighted.In light of the current regulatory and economic climate, utilities must stay focused on developing sustainable real world plans that achieve water quality goals while at the same time allow utilities to meet their customer's level of service expectations. This paper is intended to provide an overview of sustainable collection system strategies that will allow utilities to achieve these objectives.