Mamaroneck, a village whose homes and businesses sustained some of the heaviest damage in the 2007 flood, two years later will be the first target of a joint government flood reduction effort in Westchester County. Â
A series of flood abatement projects in six municipalities will cost an estimated $11.15 million, county and federal officials said. County Executive Andrew Spano in the aftermath of the disastrous flood committed $50 million in county funds over five years to aid municipalities in flood remediation projects.
In the village of Mamaroneck, the U.S. Army Corps of Engineers expects to spend 30 months revisiting and reevaluating solutions to ease flooding on the Mamaroneck and Sheldrake rivers that were first studied by Army engineers in the 1970s. The recommended project on the two rivers 20 years ago would have cost about $67 million. That cost now has risen to an estimated $150 million, of which $97.5 million would be federally funded, according to the New York district office of the Corps of Engineers.
The work recommended in 1989 on the Mamaroneck River included modifying about 10,400 feet of river channel, building about 7,200 feet of retaining walls, replacing six bridges and removing one bridge. On the Sheldrake River, engineers proposed to build a 3,550-foot diversion tunnel to Mamaroneck Harbor, 4,200 feet of channel modifications and an approximately 900-foot-long retaining wall.
“There has been a tremendous amount of study over the years of that area,” Westchester County Planning Commissioner Jerry Mulligan said last week. The Army Corps will reevaluate a range of structural and less costly non-structural options to reduce flooding “and hopefully getting the most bangs for the buck,” Mulligan said.
“They have a good idea of which way they want to go,” which could include building a major tunnel under Mamaroneck Avenue, the planning commissioner said. Still, “they don”™t have a solution in mind by any means.”
The $6.65 million project will be paid for with $5.1 million in federal funds, while the county and the state Department of Environmental Conservation each will contribute $768,000. The county”™s spending share still must be approved by the Board of Legislators. The Mamaroneck project is expected to start by late spring or early summer. Â
Spano also will seek legislative approval this year of $4.5 million in capital spending as the county”™s share of four flood reduction projects in five municipalities. A county flood task force formed by Spano in June 2007 solicited flood-related planning information from 43 communities, only 12 of which submitted preliminary project applications to the county. Four final applications have been approved.
In the town of Mamaroneck, a $1.51 million project will turn Gardens Lake into a floodwater storage facility for the Sheldrake River. The project would include the removal and redistribution of approximately 6,000 to 9,000 cubic yards of sediment from the lake, creation of lake-edge wetlands and meadows to improve water quality and fish and wildlife habitat and reconstruction of the dam at the lake”™s southern end to allow the town to draw down the lake level before a storm to detain floodwaters and decrease the river”™s velocity.
In the village of Tarrytown, an estimated $1.67 million project would make stormwater management and drainage improvements on a small tributary of the Hudson River in the vicinity of Loh Park, in the neighborhoods of Loh, Leroy and Benedict avenues. The project also would include stabilization practices to curb erosion and sedimentation.
In the village of Scarsdale, an estimated $2.9 million project would create storm water management basins and sidewalk and curb improvements to divert and detain runoff at four locations on Fox Meadow Brook, a tributary of the Bronx River that has flooded adjoining neighborhoods. The work would be done at George Field Park, Cooper Green, Brewster Road between Olmstead and Hartcourt roads and Butler Field.
In the city of Rye and village of Rye Brook, an estimated $2.2 million project would convert an existing dam on Blind Brook at Bowman Avenue into a flood mitigation structure with an automated outlet control gate. The pond behind the dam could hold stormwater to check chronic flooding problems on Blind Brook.
The county will fund half of design and construction costs for the municipal projects. To qualify, projects must address county purposes, such as lessening the risk of damage to county infrastructure and properties.
 County officials are using an additional $2 million in capital funds to investigate up to six county-owned sites where the area-wide impact of flooding might be reduced. That fund also will be used to develop a flood-impact analysis application to help the county and municipalities identify other locations for flood reduction and to assess the impact of proposed development projects on potential flooding before they are approved. Â
As part of the flood abatement effort, Mulligan said county officials also want to amend the county”™s stream control law to broaden the county”™s review authority over development projects proposed at the municipal level.
