Mamaroneck & Sheldrake Rivers Basin Village of Mamaroneck Flood Risk Management Study

Transcription

1 Mamaroneck & Sheldrake Rivers Basin Village of Mamaroneck Flood Risk Management Study Mamaroneck & Sheldrake Rivers Coastal Zone Consistency for the Harbor Coastal Zone Management Commission 20 July 2016 US US Army Army Corps Corps of of Engineers Engineers New York District BUILDING STRONG

2 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management Agenda Project Status Update Overview of Selected Plan Policies 7, 9, 17, 19, 23, 33, 38, and 44 Next Steps 2

3 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management Status Update Release of the Draft Report with Jan 29, 2016 Draft Environmental Impact Statement Public Meeting Feb 25, 2016 Public Review of Draft Report Ends Mar 31, 2016 Meeting with Village Representatives May 25, 2016 Response to Comments Posted July 11,

4 Overview of Selected Plan Channel Banks (Sloping Banks, Side Slopes, Trapezoidal) Channel Bottom (Natural, Riprap, Concrete) Walls (Retaining Wall vs. Flood Wall) Diversion Culvert Under the commuter parking lot 4

5 Channel Banks/Slopes (Trapezoidal) (East Branch Rahway River, S. Orange, NJ) 5

6 Channel Banks/Slopes (Construction) (East Branch Rahway River, S. Orange, NJ) 6

7 Channel Banks/Slopes Winter (Saw Mill River, Yonkers, NY) 7

8 Channel Bottom & Slope Riprap (Saw Mill River, Yonkers, NY) 8

9 No Flood Walls (Adams, Mass) 9

10 Only Retaining Walls (Green Brook, NJ) 10

11 Retaining Walls (Semi-trapezoidal) (Adams, Mass) 11

12 Steel Sheet Pile Retaining Wall During Construction 12

13 Retaining Walls (East Branch Rahway River, S. Orange, NJ) 13

14 Diversion Culvert (East Branch Rahway River, S. Orange, NJ) Similar to Station Plaza Culvert 14

15 Current Conditions, Poor Design (Valley Place, Mamaroneck, NY) 15

16 Current Deteriorated Walls (Hillside Ave, Village of Mamaroneck, NY) 16

17 Current Undermined Walls (Village of Mamaroneck, NY) 17

18 Current Retaining Walls (Hillside Ave, Mamaroneck River, NY) 18

19 Current Retaining Walls (Sheldrake River, NY) 19

20 Summary Channel Banks Will use sloping banks wherever possible Channel Bottom Over 90% of new bottom will remain natural Walls: No Flood Walls Most retaining walls are replacements Diversion Culvert Only 400 feet and entirely under the commuter parking lot 20

21 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 7 and Village of Mamaroneck Policy 7 State Policy 7 - Significant coastal fish and wildlife habitats would be protected, preserved, and where practical, restored so as to maintain their viability as habitats. Village of Mamaroneck Policy 7a - The following areas are identified in significant fish and wildlife habitats; and they will be protected, preserved, and where practical Delancey Cove Greacen Point Marsh Ginsberg Hill (Fusco property) Guion Creek Salt Marsh Kirstein Cove/Buttenweiser Is./Pops Rocks Magid Pond Otter Creek Salt Marsh Van Amringe Mill Pond 21

22 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 7 and Village of Mamaroneck Policy 7 HCZMC Determination Not Consistent USACE Determination N/A Project does not involve areas of significant or critical fish and wildlife habitat Project is not within any of the above identified significant areas USACE Fish and Wildlife Measures to be Conducted No in-stream work conducted from June 1- September 1 Vegetation clearing will occur August 1 April 1 USACE will revegetate the impacted streambanks with native vegetation Include rocks and riffles in stream Within the riverbank a low flow meandering channel 22

23 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 9 and Village of Mamaroneck Policy 9 Expand recreational use of fish and wildlife resources in coastal areas by increasing access to existing resources, supplementing existing stocks, and developing new resources. HCZMC Determination Not Consistent Design of observation and or fishing platforms can be added. USACE Determination Consistent Project not related to recreational uses of coastal fish and wildlife resources. Project will not impede the future expansion of recreational uses. Retaining walls will be level with the existing landward ground or no higher than 1 foot allowing access to the rivers. 23

24 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 17 and Village of Mamaroneck Policy 17 State Policy 17 Non-structural measures to minimize damage to natural resources and property from flooding and erosion shall be used whenever possible. Village of Mamaroneck Policy 17 Whenever possible, use nonstructural measures to minimize damage to natural resources and property from flooding and erosion. Such measures shall include: The setback of buildings and structures The planting of vegetation and the installation of sand fencing and draining The reshaping of bluffs The floodproofing of buildings or their elevation above the base flood level 24

25 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 17 and Village of Mamaroneck Policy 17 HCZMC Determination Not Consistent Recommends non structural storm water retention incentives in the entire watershed outside of the local jurisdiction Recommends dredging the Larchmont and Waterworks reservoirs USACE Determination Consistent The Selected Plan includes the implementation of non-structural measures for nine properties The District investigated the dredging of the reservoirs and determined that it was not technically nor economically feasible. 25

26 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 19 and Village of Mamaroneck Policy 19 State Policy 19 Protect, maintain, and increase the level and types of access to public water-related recreation resources and facilities. Village of Mamaroneck Policy 19 Protect, maintain and increase the levels and types of access to public water-related recreation resources and facilities Priority shall be given to public beaches, boating facilities, fishing areas and waterfront parks 26

27 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 19 and Village of Mamaroneck Policy 19 HCZMC Determination Not Consistent Opportunities to design footpaths USACE Determination Consistent The project will not impede access to the river for recreational uses. The project will continue to allow access to the rivers through Columbus Park. At least one footbridge in Columbus Park will be replaced. The constructed retaining walls will be level with the existing landward ground or no higher than 1 foot allowing access to the rivers. This will allow for future recreational development (walkways, fishing areas, etc.) along the riverbank. USACE is not authorized to improve public access such as designing new footpaths. 27

28 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 23 and Village of Mamaroneck Policy 23 Protect, enhance, and restore structures, districts, areas of sites that are of significance in history, architecture, archeology, or culture of the State, its communities, or the Nation. HCZMC Determination Not Consistent The discussed Memorandum of Agreement does not include the Village USACE Determination Consistent In coordination and consultation with the NYSHPO, the Village, Westchester County Historical Society, Mamaroneck Historical Society, federally-recognized Tribe, and other interested parties, USACE will negotiate and execute a Memorandum of Agreement to mitigate for the adverse affects to the eligible historic properties, including the Ward Avenue Bridge and the stone retaining walls thematic district. The Village will be invited to be a signatory to the Memorandum of Agreement 28

29 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 33 and Village of Mamaroneck Policy 33 Best management practices will be used to ensure the control of stormwater runoff and combined sewer overflows draining into coastal waters. HCZMC Determination Not Consistent Recommends non structural storm water retention incentives in the entire watershed. Recommends Dredging the Larchmont and Waterworks reservoirs. USACE Determination Consistent The Project is designed to attenuate stormwater flows to the Mamaroneck and Sheldrake rivers that could result in, or contribute to flooding. All construction activities will be conducted in accordance with applicable federal, state, and local regulations for erosion and sediment control. Requirement NYS Pollutant Discharge Elimination System General Permit for Stormwater Discharges from Construction Activity. Site-specific Storm Water Pollution Prevention Plan Erosion and Sediment Control Plan. Temporary measures that may be implemented during construction include stabilized construction entrances, stormwater inlet protection, silt fence, and erosion control blankets. The District investigated the dredging of the reservoirs and determined that it was not technically nor economically feasible. 29

30 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 38 and Village of Mamaroneck Policy 38 The quality and quantity of surface water and groundwater supplies will be conserved and protected, particularly where such waters constitute the primary or sole source of water supply. HCZMC Determination Not Consistent Can be satisfied with a discussion of the effects the project will have on the water budget of the aquifer underlying the Village USACE Determination Consistent The Project would not affect primary or sole source water supplies. Construction activities will be designed to reduce the potential for hazardous material spills Project-specific Storm Water Pollution Prevention Plan and Erosion and Sediment Control Plan All solid wastes and construction debris generated by the Project will be transported, stored, treated, and disposed of in accordance with applicable federal, New York, and local policies. This project is not designed to alleviate groundwater flooding USACE will evaluate the potential decrease of groundwater and the aquifer during the development of plans and specifications. 30

31 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management State Policy 44 and Village of Mamaroneck Policy 44 Preserve and protect tidal and freshwater wetlands and preserve the benefits derived from these areas. HCZMC Determination Not Consistent Must be evaluated on proposed mitigation projects approved by the Village Land use Boards USACE Determination Consistent No federal or state wetland permanently impacted. USACE will apply for Village of Mamaroneck wetland permit for the area along the Sheldrake River near Fenimore Road identified on the Village wetland map. Following construction, temporary workspaces would be stabilized and revegetated by planting native vegetation. 31

32 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management Next Steps Revise Draft Report Oct 2017 Final Report submitted to HQ Dec 2017 Includes Final EIS and Draft Record of Decision (ROD) Civil Works Review Board Jan 2017 State and Agency Review Mar 2017 Includes Public Final EIS and Draft ROD Chief s Report/Draft ROD Submitted Apr 2017 to Assistant Secretary of the Army for Civil Works (ASA) Chief s Report and Final ROD Signed Jun

33 Mamaroneck & Sheldrake Rivers Basin Flood Risk Management All study documents may be found at: nnewyork/mamaroneckandsheldrakerivers.aspx Comments provided will become part of the public record for this EIS. Comments submitted will be fully considered during the preparation of the final EIS. All written comments, including names and address, will be made a part of the administrative record, available to the public under the Freedom of Information Act (FOIA). The Administrative Record, or portions thereof, may also be posted on a Corps of Engineers internet web site. 33