Leonard Park - Revitalized with Stormwater Retrofits

Over the last several years, we have been working with the Town of Mount Kisco, Rennia Engineering, Con-Tech Construction, and Legacy Supply to introduce stormwater retrofits throughout Leonard Park. We accomplished this by implementing a multi-phase installation plan, which minimized the negative impact on the park users. The last sections of this plan were completed in November of 2021 and signified the end of this momentous project!

CVS Parking Lot Stormwater Outfall - Channel Stabilization

One of the first phases of the project was the channel stabilization behind the CVS parking lot which was completed in October of 2016. After years of strong stormflows, the original channel was heavily eroded and an overall mess.  Our primary goal was to clear out the existing unhealthy vegetation and weeds to replace it with rocks that help stabilize the banks of the channel. This prevents further erosion, locking Phosphorus-rich soils in place, but also improves the health of the habitat by removing invasive species and encouraging native plant growth.

Medical Building Parking Lot - Pocket Wetland

In April 2017, Con-Tech Construction completed the second phase, which was a pocket wetland treatment system. The goal of this project was simple. The medical office located at 34 S. Bedford Road in the Village of Mount Kisco has a large parking lot that mostly drains to a single point, right near Leonard Park. Rennia Engineering Design took the project and assessed the possible options to gather and treat the stormwater at this location, ultimately deciding upon a pocket wetland. Prior to our project, this location already was a damp spot, with signs of being a wetland. However, over the years, invasive species such as Phragmites australis began to take hold of the area, minimizing the treatment capabilities. Installation of a pocket wetland was space-efficient and helped reintroduced plant species that were outcompeted by invasives while not only providing habitat for wildlife but impressive Phosphorus treatment as well!

MK-NC-22 - Southern Diversion Channels and Drainage Infrastructure

The final phase of the Leonard Park revitalization plan spreads throughout the park and occurred over the last couple years. One portion involved the clearing of invasive species along the river and the stabilization of the existing pipes which empty into the stream. We installed 10 new stormwater pipe outfalls and stabilized the banks around each pipe. There are several surface filter throughout the park as well in low areas that grab stormwater and provide Phosphorus filtration. Along the southern border of the park, near the forested areas, we installed 3 dry swales to help intersect and treat the great volumes of stormwater that would flood the ball fields after every rainfall.

The following is a video showing the before and after construction of the two Southwest dry swales.

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The map below shows all the locations that received stormwater retrofits. By taking this multi-step approach, we maximized the Phosphorus reduction entering and leaving Leonard Park in a holistic manner. This has already led to healthier waterways and habitat for native flora and fauna, along with an improved aesthetic throughout for park-goers!

Location of stormwater retrofits throughout Leonard Park
acres of land treated
Pounds of Phosphorus removed annually by project
Pounds of algal growth removed from the watershed