With over 100,000 miles of state roads in NY, transportation corridors amass a large percentage of a state's land use. Given the increasing likelihood of extreme precipitation events, threatened ecosystems and the current issues with water security, our industry can help to tackle these challenges.
This project in Aurora, NY was designed to address safety issues at the intersection of an expressway terminus and 2 local roads. The crash rate was 1.38 crashes per million vehicle miles: almost 4 times higher than the state average. A roundabout was proposed as the preferred alternative. As part of the central roundabout design, there was an opportunity to create an attractive, properly functioning, low maintenance landscape feature that also incorporated stormwater capture and groundwater recharge.
The roundabout’s concrete truck apron was designed to slope inward directing runoff to the central landscape island, a departure from the typical design that slopes the truck apron toward the road. The design of the central landscape island consists of three spiral shaped berms situated in an aggregate bed. Under the aggregate are three vertical pipes connected by three lateral pipes to create a storage reservoir. The reservoir helps to manage extreme storm events by accelerating infiltration. and allowing for eventual groundwater percolation. This is a vital part of the water cycle and must be maintained for the proper functioning of our existing ecosystems. The small-scale design helps to better manage stormwater and improve water quality via its movement through the soil ecosystem.
The central island plant materials included both drought tolerant (on the berms) and moisture tolerant (in the central aggregate) species. Most plant species are native to New York. The plants were also chosen to benefit pollinators and birds, as well as offering seasonal ornamental displays.
Completed in the Fall of 2022, this project begins to explore one way the transportation infrastructure system may be used for ecological benefit. There has been one large rain event since its construction, and the system performed as designed. NYSDOT is monitoring performance for consideration of incorporating the concept into future projects.