Municipal Stormwater Retrofits: The Unique Planning, Design, Construction, Budgeting and Maintenance Challenges

As towns and cities across the country seek to implement (GSI) retrofit projects there are a series of unique challenges that differ from managing wet weather on private site development projects. This presentation seeks to identify many of the key challenges, provide simple guidance to designers and program managers on how to plan for and account for them from planning through to post installation O&M.

Full Abstract: As towns and cities across the country seek to implement green stormwater infrastructure (GSI) retrofit projects there are a series of unique challenges that differ from managing wet weather on private site development projects. Understanding and addressing these challenges will improve the outcomes, impact, and cost effectiveness of these projects.

GSI retrofit projects are often smaller in scope, the siting/location of the practice is critical to maximize both performance and public engagement, are shoe-horned into small spaces, impact existing infrastructure temporarily, have more unknowns regarding location of existing utilities and soil conditions/geotechnical information, lack sufficient pretreatment and screening, miss opportunities to unlock to triple bottom line co-benefits of GSI, are in many cases installed by contractors less familiar with the nuances of GSI, are difficult to budget for especially when the retrofit is not part of a larger scope of work, and there is often a of lack understanding of long term maintenance needs and associated budgets.

This presentation seeks to identify many of the key challenges associated with GSI retrofit projects that are unique when compared to private site development projects, provide simple guidance to designers and program managers on how to plan for and account for them from planning through to post installation O&M. some discussion will also be included centered on the long term O and M costs and the eventual replacement value of GSI practices. The presentation will encourage listeners to adapt their processes to account for the many challenges and to work collaboratively to improve GSI retrofit outcomes. Examples for NYC ROW retrofit work and the Philadelphia Green city, clean waters program will be referenced.