Pemberwick Park Drainage Area Improvements
Following the impacts of Tropical Storm Ida, the Town of Greenwich Department of Public Works (DPW) began to review several areas in the Town for alternatives to reduce the impacts of future storms. It was determined one area of the Town that required further study is the Pemberwick Park drainage area. This project includes drainage improvements to the Pemberwick Park area, including modifications to an existing headwall, replacement of a trash rack, and installation of a new drainage pipe to increase the drainage capacity to a 100-year storm. The new catch basins include two-foot sumps to trap sediment. To prevent erosion during large storm events riprap will be placed along the south corner of the trash rack headwall. Restoration of the ball field, park turf, sidewalk, curbing, and pavement will take place upon completion of the installation of the new drainage pipe.
The Town of Greenwich Department of Public Works (DPW), Engineering Division, has filed an application with the Inlands Wetlands and Watercourse Agency (IWWA) for the proposed work to be reviewed at their meeting on August 28, 2023. Design plans have been completed so that the contractor can commence with pipe installation, headwall modifications, and trash rack replacement upon IWWA approval.
- Raise the existing trash rack headwall to 44.5 feet elevation.
- Replace and install an extensive trash rack grate system.
- Install new catch basins including two-foot sumps to trap sediment.
- Chip the existing boulder at the north corner of the headwall to widen the channel.
- Install an additional drainage pipe parallel to the existing pipe to increase the capacity of a 100-year storm and prevent overtopping.
- Install a new 24-inch pipe (in the park area) that will run from the headwall to Pemberwick Road and a new 36-inch pipe will run from Pemberwick Road to the outfall at the Byram River via Rex Street.
- Install modified riprap for the south corner of the wing wall to stabilize the slope, and grading behind the south portion of the wing wall.
Hydraulics and Drainage
A detailed Storm Water Management Model (SWMM) watershed and hydraulic conveyance model analysis was performed to evaluate existing and proposed conditions. Appropriate hydrologic methods were used to estimate the flows through the watercourse. The hydraulic model was run for both the existing and proposed conditions for the various scenarios. The proposed improvements will result in conveying more flow than existing. The proposed changes do not have any adverse impacts on residential properties or Federal Emergency Management Agency (FEMA) elevations.
- 2022 -- detailed Storm Water Management Model (SWMM) watershed and hydraulic conveyance model analysis was performed to evaluate existing and proposed conditions.
- 2022 -- develop plans for the project.
- November 9, 2022 -- public meeting.
- August 2023 -- filed project application with the Inlands Wetlands and Watercourse Agency (IWWA) for the proposed work.
- Fall 2023 -- Anticipated start of project construction.
This is a Town of Greenwich Department of Public Works project with design completed by the Town and construction funded through the American Rescue Plan Act of 2021 (ARPA).
DPW hosted a public meeting on November 9, 2022, to provide the status of the project.
CLICK HERE to view the presentation.
Project Manager: Gabriella M. Circosta Cohee, P.E., Town of Greenwich Department of Public Works Chief Engineer
- Email: Gabriella.Cohee@greenwichct.org
- Phone: 203-861-3151