Green Infrastructure Research and Development (GIRD)

Boomi assisted NYC DEP with this R&D effort geared towards making informed decisions on stormwater controls such as ROW GI, and their construction/post-construction requirements in MS4 areas

Project Owner

New York City Department of Environmental Protection (NYC DEP) - Bureau of Environmental Policy and Analysis (BEPA)

Project Location

New York City

Project Context

Under a SPDES permit, the NYC DEP has been working to quantify the benefits achieved from implementing green infrastructure in MS4 drainage areas.

Boomi assisted DEP with this effort and led the task on lot size soil disturbance threshold study and a cost-benefit analysis to help DEP make informed decisions on construction and post-construction stormwater control requirements in MS4 areas.

Project Challenge

When this project was initiated there were no SOPs available in the literature related to construction/post-construction requirements for stormwater control measures (SCMs). Similarly, the methodology to estimate baseline pollutant loads were not clearly defined. This R&D effort required the consultant team to develop SOPs based on fundamental principles.

Our Solution

Through extensive watershed delineations and reconciliations performed in GIS, and through a detailed literature survey on construction/post-construction stormwater control measures (SCMs) implemented as part of new and redevelopment projects in other urban cities, our team developed an hierarchical approach for the SCMs. A distributed GI modeling approach was also developed to quantify the results for each of the sewersheds within the city.

InfoWorks CS model was used to develop the baseline (without SCMs) flows into various water bodies. Event mean concentrations (EMCs) were used for the five water quality parameters of concern (total nitrogen, phosphorus, total suspended solids, fecal coliforms, and enterococci) to estimate baseline pollutant loads. Removal efficiencies for SCMs were then used to assess the pollutant load reductions for each threshold lot size for development of benefit-cost curves.

The analyses we provided were used by DEP to establish the construction and post-construction stormwater control requirements in MS4 areas as part of the unified stormwater rule (USWR) published in 2021.