Guide to Managing Peak Wet Weather Flows in Municipal Wastewater Systems

The Water Environment Federation (WEF) is pleased to share our new publication, Guide to Managing Peak Wet Weather Flows in Municipal Wastewater Collection and Treatment Systems.

How was the guide developed and reviewed?
The guide was developed under a Water Quality Cooperative Agreement between WEF and the U.S. Environmental Protection Agency. The document was prepared by CH2M HILL, Inc., and Water Resources Strategies under the guidance of a project steering committee composed of WEF members. Drafts of the document were reviewed by the project steering committee, a technical review group composed of members of various WEF technical committees and individuals with specific expertise, and stakeholders who volunteered to provide input.

Who is it for and why?
The guide is intended for owners, planners, designers, and operators of wastewater collection and treatment systems and provides information for making decisions on how to improve wastewater treatment and collection system performance during wet weather. Publicly owned treatment works (POTWs) have a limited ability to control highly variable wet weather flows, and the burden is on the POTW to support its planning and performance. As a result, POTWs must be aggressive in proposing alternatives and assessing impacts, be proactive in explaining the benefits, and talk with regulators and the public. The WEF Guide provides a method for POTWs to be more proactive in planning for wet weather flows and describes a process that can be used to build support for real-world solutions that effectively use resources to improve water quality.

How is the information relevant to current EPA wet weather initiatives?
In December of 2005, EPA proposed a Peak Wet Weather Discharge Policy that applies the bypass standard of “no feasible alternatives” to wet weather diversions at POTWs serving sanitary sewers. If finalized, the policy will require a comprehensive utility analysis to identify and assess alternatives, and will not allow diversions when peak flows are largely due to poor collection system maintenance or lack of investment in capacity. The WEF guide presents a facility planning and management approach that brings detail to the general framework of the EPA Peak Wet Weather Discharge Policy’s utility analysis. It includes considerable peer reviewed information on effective technology alternatives and practices for managing peak wet weather flows and will support implementation of the EPA policy.

What is in the guide and how is it organized?
The guide is presented in three sections: Introduction, Principles for Wet Weather Management, and Guidance Practices. The Introduction section presents background information, the purpose of the guide, a glossary of terms taken from existing authoritative references, and a list of acronyms and abbreviations. The Principles for Wet Weather Management section includes three key elements upon which the guide was developed: a wet weather management framework, a list of wet weather management principles that emphasize a holistic planning approach and recognize experience-based criteria, and a method for applying proven risk-management concepts to the definition of wet weather performance objectives. It outlines a structured process that combines stakeholder input, community values, and technical approaches to compare alternatives. The final section, Guidance Practices, describes generally accepted practices that were compiled by gathering information from wet weather management practitioners. The section is organized into subsections about planning, management, and operating and maintaining, all key components of overall management activities. 

How do I order a copy?
PDF copies of the guide are available at http://www.e-wef.org. Printed copies will be available soon.