LETTER: Mayor Cohn & the Council on the Flood Response Post Ida

In a letter to MyRye.com, Mayor Josh Cohn and the six members of the Rye City Council want you to know there is a flood of activity and focus in the wake of the Ida storm last August in regards to what Rye and others need to do to mitigate future flood events.

Here is the letter from City Councilmembers Benjamin Stacks, Julie Souza, Josh Nathan, Carolina Johnson, Emily Hurd and William Henderson and Mayor Josh Cohn:

Eight months have passed since Ida and flood response is a dominant City Hall topic. Yet the nature and scope of the effort that City government is making to respond to the threat of future flooding is not well-known. The following is intended to make the City’s effort transparent.

Introduction 

Since Ida, Mayor, Council and City staff have been heavily involved in a wide range of efforts to respond to residents’ immediate post-storm needs and to reduce the risks from future storms. This heavy involvement will need to continue, unabated, until remediation and mitigation both are substantially advanced. Just as Ida may have represented a paradigm shift in storm intensity, so Ida requires a paradigm shift in Rye municipal response. The present City Hall tenants understand that well and will share that understanding with their successors over time.

Ida, with its sudden intensity, brought us our first flash flood in memory on Blind Brook, as well as flooding along Beaver Swamp Brook. Ida’s rain produced surface stormwater flooding in parts of the City where that was uncommon or unknown. Ida exceeded our 100-year flood map. These circumstances require us to search every avenue for technical and funding assistance as we anticipate the next outperforming storm. Just as we may face a greater degree of risk, we are making still greater efforts to diminish that risk.

We have to recognize that this must be a long-term City discipline. Our neighbors in Mamaroneck and Port Chester are poised to receive substantial federal funding for flood control projects, but only after many years of project development and consistent pursuit of that funding. We are prepared both to work quickly, where quick work will be rewarded, and to persevere, where perseverance will bring our City the safety it needs.

Following is a partial list of flood-related City initiatives taken or in process. The list describes current status, but does not describe the many steps taken on the path to this list or the multiple possibilities that may follow and that will require this list to be updated from time to time.

New York Rising Projects – These projects have been pending for years and are only now approaching completion. They are: installation of Blind Brook stream gauges to allow computerized, flow-sensitive operation of the Bowman Dam sluice gate; limited debris clearing in the Bowman Dam impoundment area; and enhanced flood drainage at the south end of Milton Road. The projects, although helpful, will not by themselves substantially mitigate Blind Brook flooding.

Engineering Studies

The City, in the first instance, must make cost-efficient spending decisions going forward. Beyond the City’s own obligation, many funding sources require that potential projects show positive, engineer-developed and current cost-benefit analyses. Many funding sources also require that potential projects have reached a certain stage of engineering development prior to funding. Although there have been over past decades many studies of Blind Brook flood mitigation (including tidal effects), none of the studies are sufficiently current and projects previously identified are not ready for decision making. Accordingly, further engineering studies are needed to advance project choice.

Ramboll – Since Ida, the City Council has retained Ramboll Americas Engineering Solutions to undertake a comprehensive review and analysis of the Blind Brook watershed. The stated goal of the City and direction to Ramboll is to identify potential, viable flood mitigation measures. Ramboll has been involved in previous work in the Blind Brook watershed and knows the terrain.

Ramboll has held meetings with various stakeholders, reviewed past studies and undertaken field investigation. Ramboll is expected to return in May to discuss with the City Council an initial prioritization of leading projects among the score initially considered in scope.

NYS Department of Environmental Conservation – For the first time, the City has been fortunate in engaging DEC in study of mitigation possibilities in the Blind Brook watershed. DEC also has agreed to undertake a study of Beaver Swamp Brook. Each of these studies will involve our municipal neighbors in the respective watersheds, as well as state elected officials and county officials. Multiple intermunicipal meetings have been held, also involving our state delegation and the county. The Blind Brook study began in January and is expected to take 8 months. The DEC study team met with a City team recently and reviewed flood impacts within the City and potential mitigants. The DEC effort, in general, is to discover projects that are near-term feasible.

US Army Corps of Engineers – USACE is pre-eminent in flood control projects, though USACE has a reputation for an expensive and time-consuming process. Mamaroneck, for example, appears to be nearing the fruition of more than a decade of USACE and congressional review. The City met with USACE in 2019, leading to a preliminary study that served as the basis for USACE’s 2021 federal interest determination. This determination opened the door to further USACE study, however that further study may require both NYS and City sponsorship, in part. NYS DEC has expressed interest in the study going forward. Senator Schumer has indicated that we have a $350,000 grant to open the study, but that amount may be dwarfed by the projected cost of the “general investigation” study of the watershed that may be appropriate. USACE has informed us that they are beginning the study, though study parameters are not yet set.

Stormwater Flooding– Ida, which followed Hurricane Henri’s soaking rain, taught us the limitations of the City stormwater system (which is separate from our sanitary sewers). The City Engineer has circled approximately a dozen discrete areas that had stormwater/runoff flooding issues in Ida, and each of those areas is being studied, reviewed with the City Council and being considered for cost-effective mitigation

Other (Non-Engineering) Initiatives

US Department of Agriculture – Natural Resources Conservation Service – This agency specializes in flood plain management and restoration, with the latter discipline being potentially applicable to Rye. In preliminary conference with NRCS about their buyout program (buying out and removing flood-threatened homes to restore flood plain) we learned that NRCS typically deals in whole neighborhood buyouts in real estate markets less expensive than Rye’s. We expect more information, but think this agency may find it hard to help us.

Westchester County – Besides meeting with the county in periodic DEC sponsored conferences, we have met directly with county senior staff to underscore our flooding related needs with respect to riverine flooding, stormwater flooding and tidal flooding. County staff understands our needs and indicated that they will be inclined to respond to those needs when accessible funding is available. With respect to stormwater flooding in particular, the county has indicated that it wishes to resolve problems with Midland Avenue drainage before it repaves Midland, as expected this paving season.

Neighboring Municipalities – we have had meetings with the leadership of our neighboring municipalities of Port Chester, Rye Brook and Harrison and have elicited their expressions of support for flood mitigation in our common watersheds.

SUNY – Purchase – Historically, flood control impoundments in forested land on the Purchase campus have been proposed, but in the past the administration of Purchase College has been opposed. We have met with Purchase campus staff, who have voiced interest in exploring such a project. Our state senator and assemblyman have had similarly positive conversations with the administration.

“Upstream Electeds” – We have consulted with, and in some cases already have been aided by, our elected representatives in Congress, the NYS Legislature and the county government.

Funding Consultants – In addition to our grant consultants and our newly-hired NYS funding legislative specialist, we are conducting a search for consultants who will be able to help us find our way through the specialized opportunities open under federal law (enhanced now by a variety of laws) to find funding for the mitigation projects we hope to undertake. We are likely to hire in the near future.

Emergency Response and Planning – Work is underway on a number of emergency preparedness and response steps, such as:

• Establishing a new emergency operations
• Creating new communication options among all City personnel during a state of
• Requiring senior staff (non-PD, FD) personnel to receive Incident Command
• Creating a swift water rescue
• Acquiring additional emergency equipment, specifically flood related
• Enhancing and evolving our resident communication strategy for
• Creating improved emergency housing plans and assisting storm hardening

Conclusion

Flooding in Rye is attributable to our brooks overflowing, surface water accumulation and tidal/coastal intrusions. These problems, in some locations, may be historical, but without the flood levels and vulnerability we experience today. Today, we as a city are required to seek as many avenues of assistance as we possibly can to overcome what has become a manifest threat to life and property. This search must be constant and continuing to bring the City the cost-efficient and funded mitigation projects it needs. Our present City administration, both elected officials and staff, is dedicated to this goal.