The City of Waltham, Massachusetts is dedicated to reducing the impacts of climate change to the city’s buildings and infrastructure, environment, and vulnerable populations. In fact, they have identified flooding related to climate change as their most prevalent and serious natural hazard. To help respond, the city retained Weston & Sampson to help them procure grant funding from the Commonwealth of Massachusetts’ Municipal Vulnerability Preparedness (MVP) Action Grant Program to support a Resilient Stormwater Action and Implementation Plan to address the city’s vulnerable stormwater infrastructure. The objectives of this project are to:
- develop a comprehensive and resilient management and implementation plan for the stormwater system;
- identify priority stormwater projects and key areas to equitably incorporate green infrastructure;
- evaluate projects to more efficiently direct future resources; and
- better maintain, protect, and improve the assets and natural resources of the city through proactive stormwater management.
Weston & Sampson began by collecting historic flood information, reviewing the city’s stormwater infrastructure GIS, and conducting a field reconnaissance survey. Our field survey helped fill data gaps and verify the locations and conditions of natural and manmade stream deficiencies, drainage manholes, catch basins, outfalls, culverts, and other stormwater infrastructure. Using this data, the project team created a hydraulic and hydrologic model to inform the development of green infrastructure and flood mitigation projects in addition to quantifying their potential benefit. Green infrastructure techniques such as stormwater infiltration basins, bioswales, rain gardens, and others are climate resilience best management practices. To ensure proper design of these features, we evaluated the potential effectiveness of both green and grey infrastructure improvements under a range of design storm events and under baseline and future climate conditions. After considering all 300+ projects, we worked with the city to prioritize the projects based on their contributions to the community, including those specifically benefitting environmental justice neighborhoods and the ability to reduce the urban heat island effect.
The city’s Resilient Stormwater Action and Implementation Plan provides a clear understanding of the stormwater drainage system existing conditions and a 10-year capital improvement plan focused on equitable climate resilience solutions. The plan is a proactive approach and, upon implementation, will avoid many costs related to updating infrastructure and reducing flood risk.
During the plan’s development, we also advanced the city’s MS4 permit efforts by providing recommendations on how to incorporate climate resiliency into their illicit discharge detection and elimination protocol and other stormwater regulations. In addition, the project team created a pilot catch basin cleaning program that could be replicated for other stormwater assets. The tracking program allows for catch basin conditions and maintenance to be documented in the field to update the city’s GIS database in real time. Lastly, development of the plan involved online public engagement efforts by developing a video series, online survey, and fact sheet.
- field survey and reconnaissance
- stormwater modeling to ensure proper design
- green infrastructure
- illicit discharge detection and elimination
- community engagement