FLOOD STUDY Rockland County, NY FEMA REGION II April 13, 2011

Agenda Introductions and Roll Call Objectives Map Modernization (MapMod) Program Overview Rockland County MapMod Update Milestones Questions & Feedback

Introductions and Roll Call Local – Rockland County & Communities New York State Department of Environmental Conservation (NYSDEC) Floodplain Management Section Chief: William Nechamen, CFM Environmental Engineer: Kelli Higgins-Roche, CFM Project Engineer: Arvind Goswami, PE Mapping Partner (NY State Subcontractor) – URS Project Manager: John Dromsky-Reed, PE, CFM FEMA Region II Project Officer: Alan Springett Communications / Outreach Support: Adie Koby Floodplain Management and Insurance Lead: Richard Einhorn & Patricia Griggs RSC Deputy Coordinator: Tolga Yilmaz, CFM, GISP RSC Outreach Lead: Crystal Smith, CFM

Objectives Objectives To provide an overview of Rockland County’s flood hazard mapping project status To promote community engagement and enhance capability to effectively manage flood risk

Map Modernization (MapMod) Program Overview Prior to 2003, more than 70 percent of the nation’s flood maps were at least 10 years old. In Rockland County, with few exceptions, the communities' flood maps dated back to the 1980s Congress appropriated funds in 2003 and directed FEMA to develop and implement the MapMod program, which: Created county-wide digital maps Utilized more current data to update maps Developed a new platform to convert from paper to digital format

Rockland County MapMod Update Scope of Rockland County study County-wide DFIRM (64 panels), including 24 incorporated communities 51 miles of new detailed riverine study Re-delineation of 74 miles of detailed studies (Rivers & Lakes) Re-delineation: Previously identified floodplains and associated detailed flood elevations paired with updated topographic data (LIDAR) that retains the integrity of the existing Engineering analysis Analysis of 33 approximate stream miles Approximate Stream: The discharges for the approximate study streams were calculated using the 2006 New York regression equations for drainage points with basins >2.0 square miles. The equations were adjusted for urbanization using the USGS/Sauer method, utilizing ortho-imagery, MRLS data, and USGS mapping. For smaller basins, the rational method was used. The DFIRM and FIS report produced in the FEMA Countywide format in the North American Vertical Datum of 1988 (NAVD88) NAVD 88 = NGVD 29 – 0.9 (average) Preliminary DFIRMs delivered on March 31, 2011 894.0’ NAVD 88 894.9’ NGVD 29 Elevation in NGVD 29 Elevation in NAVD 88 896.0’ 896.9’ Datum Conversion of Rockland County

Vertical Datum Conversion Factors FLOODING SOURCE   CONVERSION FACTOR (NGVD 29 TO NAVD 88) (FT) Antrim Creek -0.90 Brian Brook -0.89 Cedar Pond Brook -0.98 Crumm Creek -0.96 Demarest Kill -0.97 East Branch Hackensack River East Branch Saddle River -0.93 Golf Course Brook -0.91 Hackensack River Hudson River -0.99 Hungry Hollow Brook -0.94 Lake Deforest Mahwah River -0.88 Mill Creek Minisceongo Creek Montebello Creek Muddy Creek Nakoma Brook -0.83 Nauraushaun Brook North Branch Pascack Brook Pascack Brook -0.95 Pine Brook FLOODING SOURCE   CONVERSION FACTOR (NGVD 29 TO NAVD 88) (FT) Ramapo River -0.85 South Branch Minisceongo Creek -1.08 Sparkill Creek -0.99 Spook Rock Brook -0.91 Spook Rock Brook Left Channel Stony Brook -0.84 Tributary 1 to Hudson River -0.98 Tributary 1 to Nakoma Brook -0.81 Tributary 1 to Ramapo River -0.87 Tributary 1 to West Branch Saddle River -0.93 Tributary 2 to Ramapo River Tributary to Cedar Pond Brook -0.97 West Branch Hackensack River West Branch Saddle River Willow Tree Brook -0.90

Rockland County-wide Paneling Scheme Some of the communities that did not have maps might get new maps with special flood hazard zones Some of the communities may be covered with more than one panel Paneling scheme created from 1:24,000 USGS quads Town of Stony Point

Local Communities Roles & Responsibilities of Local Communities: On March 31, 2011 each community received: Preliminary Flood Insurance Study (FIS) report Preliminary Paper Flood Insurance Rate Maps (FIRMs) DVD containing digital FIRM & FIS & fact-sheet and geographic information system (GIS) data: GIS viewer and preliminary shapefiles Roles & Responsibilities of Local Communities: Review & Comment on these preliminary FIRMs & FIS FEMA & NYSDEC will be conducting CCO meetings early summer Flood Risk communications with residents

Milestones December 2005: Rockland County scoping meetings Fall 2006: Rockland County-wide Flood Insurance Study/Flood Insurance Rate Maps funded March 31, 2011: Preliminary Rockland County Flood Maps delivered Early Summer 2011: CCO meetings with the community officials followed by Open House meetings Summer 2012: Letter of Final Determination (LFD) Early 2013: Effective Flood Maps delivered

Post-Preliminary Process

Mitigation Plan in NY Update

Resources New York State - NFIP Coordinator: http://www.dec.ny.gov/ New York State Office of Emergency Management: http://www.semo.state.ny.us/ FEMA: www.fema.gov Floodsmart, the official site of the National Flood Insurance Program (NFIP): www.floodsmart.gov Risk Assessment, Mapping and Planning Partners: www.RAMPP-team.com NFIP Reform: www.fema.gov/business/nfip/nfip_reform.shtm

Questions & Feedback www.RAMPP-TEAM.com/ny.htm: PowerPoint Presentation & fact sheet & FIS & FIRMs & additional information will be posted Contact Information New York State Department of Environmental Conservation (NYSDEC) William Nechamen, CFM Kelli Higgins-Roche, CFM Arvind Goswami, PE 518-402-8185 518-402-8185 518-402-8185 Wsnecham@gw.dec.state.ny.us Kahiggin@gw.dec.state.ny.us Aggoswam@gw.dec.state.ny.us URS - Mapping Partner John Dromsky-Reed, PE, CFM 973-785-8013 x 350 John_Dromsky-Reed@urscorp.com FEMA Region II Alan Springett Richard Einhorn 26 Federal Plaza, 212-680-8503 New York, NY 10278 Richard.Einhorn@dhs.gov 212-680-8557 Alan.Springett@dhs.gov