Flooding is one of the greatest climate change impacts Irvington is experiencing already. Irvington’s comprehensive Village-wide flood study was initiated in 2009, to identify areas of chronic or potential flooding and recommend measures to correct or control future flooding.
The study was presented to the public in 2011 and has helped Irvington to plan construction projects and win numerous grants to expand culverts that were built more than 100 years ago and need to be expanded to manage growing drainage needs. This includes a Climate Smart Communities grant for $1,136,000 for improving the water flow of Barney Brook under Broadway by Harriman Road and another $1,4000,000 to upgrade the culvert under Broadway by Downingwood.
Photo credit Frederick Charles
Community Resilience Building
In addition to the flood study, the Villages of Dobbs Ferry, Hastings-on-Hudson, Irvington, Sleepy Hollow, and Tarrytown participated in a Community Resilience Building Workshop in March of 2020, to identify key vulnerabilities. Find the report here. Find the Community Building Risk Matrix summary here.
Scroll down for Village stormwater management code and flood prediction resources.
Flood Mitigation Projects
Find long-range capital project plans on the Village website here: https://irvingtonny.gov/451/Long-Range-Capital-Plans
As described above, Barney Brook , under Broadway by Harriman Road, requires a major overhaul, expanding from a 3 foot by 3 foot pipe to a much wider outlet (as much as 25 feet), to accommodate increasing precipitation and the combined flows from the Irvington Reservoir, Halsey Pond and surface runoff. In December of 2023, the State gave a $1,136,000 matched grant to the Village to replace the culvert. The project will focus on the western end of Harriman Road, widening the channel under Broadway and replacing the culvert at the west end of the intersection. While the timeline for the project is broad, the Village hopes to start construction by the end of this year and projects it will take 12 to 18 months to complete the culvert replacement. Read the Rivertowns Enterprise article about it here.
Downingwood and Broadway
According to the Rivertowns Enterprise: Kathy Hochul announced July 5 that the Village would receive $1.4 million in state funds to upgrade the culvertthat runs under Broadway (Route 9) at the entrance to the Downingwood condominium development. The work at Downingwood, which is south of Harriman Road,is estimated to cost $1,869,800, and will replace 155 feet of a 100-year-old drainage structure with a new, wider, box culvert. Included in that estimate is $1,266,745 for construction and $317,000 for design work, the latter of which may be complicated by gas and water lines along Broadway. Those might have to be relocated depending on the path of the new culvert. Finally, the grant application estimates a cost of $171,000 for inspection once the construction is completed.
Irvington Reservoir Dam
The New York DEC regulates dams and has ranked the reservoir dam Class C, with a risk to life and property should it fail. Class C dams most follow certain protocol, including a safety study every 10 years as precipitation levels increase and structures shift. It is important to know not only that the structure will withstand increased pressure, but that the water will not flow over the top. The 120+ year old dam was close to being deficient at the last study, so it is anticipated that significant work will be required at the end of this one. The study results are anticipated in the spring.
Halsey Pond Dam
Also rated a Class C dam, a study in underway to determine necessary upgrades. Some mitigation efforts have already been deployed. The study results are anticipated by spring at the latest, though the recommendations are not expected to be as significant as for the reservoir.
The Village continues to work with engineers to assess and design solutions for various additional projects from Sunnyside to Sycomore Lane and the Ardsley train station. Some depend on collaboration with the MTA, Historic Sunnyside, the Town of Greenburgh or the Village of Tarrytown. All are in process and discussed monthly at the Village Engineering Projects meeting.
Scenic Hudson provides its Sea Level Rise Mapper for the Hudson River. This tool uses high-resolution LiDAR topography to produce graphics of high tide and 1-percent flood zones for sea-level rise of up to 72 inches in 6 inch increments. https://scenichudson.maps.arcgis.com/apps/MapJournal/index.html?appid=3a3d0dc3884c4637ad0a51f4aa912189
The New York State Department of State prepared maps of coastal risk assessment areas with assistance from the NOAA Coastal Services Center (NOAA-CSC) and FEMA. Areas covered are New York City and Suffolk, Nassau and Westchester counties. The maps indicate relative risk (extreme, high and moderate) using the best available topography and a combination of information from FEMA flood insurance rate maps; Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model inundation zones; and sea-level rise and shallow coastal flooding scenarios. http://nysandyhelp.ny.gov/risk-assessment-maps