Green Infrastructure Implementation in Urban Parks for Stormwater Management

A rain garden was constructed in Shoelace Park in Bronx, New York with the goal of capturing stormwater runoff generated on part of 228th Street. As a pilot study implemented to test the overall strategy of utilizing urban park space to manage street runoff, the rain garden was monitored over a ten month period from October 2014 to July 2015. Field observations and analysis of the stormwater runoff entering the site through an inlet on 228th Street indicate that, due to the contributions from many adjacent tributary areas, the rain garden receives more water than anticipated. Results of the monitoring campaign show that the stormwater inlet on 228th Street captures runoff from an effective catchment that is about 1.6 times the designed tributary area. The rain garden retained an average of 77% of all inflows for all storms with water typically leaving the system in storms over 1 cm. It retained 96% and 45% of all inflow for all storms less than 1 cm and greater than 1 cm in total precipitation, respectively. The rain garden managed all off-site runoff from an area of 228th Street that was about 9 times its size during a 2.5 centimeter storm while receiving additional runoff from other adjacent areas. New York City is 72% impervious and 19.5% parkland. With as little as 5% of all New York City urban park space retrofit with green infrastructure performing similarly to the Shoelace Park rain garden, runoff from 35% of New York's impervious surfaces can be treated. This limited impact to the park ameliorates concerns of infringing on the park's current recreational purpose. Other cities in the United States with high impervious coverage and available park space are urged to consider this stormwater management opportunity.