VILLAGE OF SCARSDALE WESTCHESTER COUNTY, NEW YORK COMPREHENSIVE STORM WATER MANAGEMENT SOUTH FOX MEADOW STORMWATER IMPROVEMENT PROJECT In association with WESTCHESTER COUNTY FLOOD MITIGATION PROGRAM Rob DeGiorgio, P.E., CPESC, CPSWQ The Bronx River Watershed Fox Meadow Brook Bronx River Watershed Area in Westchester 48.3 square miles (30,932 acres) 15 Sub-watersheds Percent of undeveloped land in the Watershed 3.3% (0.8 acres in Fox Meadow Brook (FMB) FMB watershed) 928 acres (5.7% of watershed) Bronx River Watershed Fox Meadow Brook George Field Park High School Duck Pond Project Philosophy and Goals •Provide flood mitigation within the Fox Meadow Brook Drainage Basin. •Reduce peak run off rates in the Bronx River Watershed through dry detention storage. •Rehabilitate and preserve natural landscapes and wetlands through invasive species management and re- construction. •Improve water quality. • Petition for and obtain County grant funding to subsidize the project. Village of Scarsdale Fox Meadow Brook Watershed SR-2 BR-4 SR-3 BR-7 BR-8 SR-5 Village of Scarsdale History •In 2009 the Village completed a Comprehensive Storm Water Management Plan. •Critical Bronx River sub drainage basin areas identified inclusive of Fox Meadow Brook (BR-4, BR-7, BR-8). •26 Capital Improvement Projects were identified, several of which comprise the Fox Meadow Detention Improvement Project. •Project included in Village’s Capital Budget. •Project has been reviewed by the NYS DEC. •NYS EFC has approved financing for the project granting Scarsdale a 50% subsidy for their local share of the costs. Village of Scarsdale Site Locations – 7 Segments 7 Project Segments 1. George Field Park Dry Detention Pond 2. Cambridge Road Clean, Televise, Line CMP pipe, add positive drainage 3. Cooper Green Dry Detention Pond 4. Open Stream Along Post Road De-silting/re-channelization 5. Murray Hill Dry Detention Pond 6. Gravel Parking Lot at the High School Raise the lot 7. Harcourt Woods De-silting/ re-channelization Segment No.1 - George Field Park (Overview) Post Rd 80 ft Dry Detention Basin Wetland Greendale Rd 800 ft Oxford Rd Oxford Segment No. 1 - George Field Park (Wetland) •Rehabilitated, re-constructed wetland •Enhances water quality •Improves bio-habitat •Eliminate invasive species (Japanese Knot Weed, Norway Maples…) •Dry detention – 7 acre feet of storage (2,300,000 gals) •1 to 3 feet overall depth Segment No. 1 - George Field Park (Pedestrian Bridge) •Stream bank stabilization •Passive recreation Segment No. 1 - George Field Park (Outlet) •Greendale Road side Grassy swale – water quality improvement •New trees and vegetation Segment No. 1 - George Field Park (Section View) Segment No. 2 - Cambridge Road • Cleaning, televising, and potentially lining the drain pipe from George Field Park to Cooper Green • Installing positive drainage in the low lying area WORK WILL BE COMPLETED ON PRIVATE PROPERTY AND AN AGREEMENT WILL HAVE TO BE REACHED WITH THE HOME OWNER(S) Village of Scarsdale Segment No. 3 - Cooper Green Post Road Dry Detention Pond Pervious walkway / rain garden Grey Twig Dogwood New England Aster Witch Hazel Cut leaf Cone Flower Native Rain Garden Plantings Wild Beramont Switch Grass Inkberry Holly Spotted Joe-Pye Weed Cardinal Flower Great Blue Lobelia Elderberry Red Milkweed Winterberry Segment No. 3 - Cooper Green (Section View) •2,900 square feet of Rain Garden along pervious walkway •One of largest Rain Gardens proposed in the Hudson Valley •2.5 acre-feet of run off storage (815,000 gals) Segment No. 4 - Open Watercourse Re-Channelization Along Post Road • The stream will be desilted to restore the optimal geometry of the stream. • Work to be completed on private property – requires access agreements. Village of Scarsdale Segment No. 5 - Murray Hill/Post Road FLOW FROM ALONG •2.5 acre feet of storage POST ROAD (UPPER FMB) (815,000 gals) FLOW FROM MURRAY HILL ROAD •Helps eliminate bottle neck at confluence at Murray Hill/Post CONFLUENCE Road more so than reducing POINT OF FLOWS overall peak flows •Involves Land Acquisition – to be determined by Board of Trustees •Not part of the project planned for bidding in December 2011 Segment No. 6 - High School Parking Lot Flood Mitigation • Chronic flooding at High School lot. •Identified Project in Village’s Comprehensive Plan. •Beneficial re-use of excavated soils. •20,000 cubic yards of soil to be un-earthed at George Filed Park and Cooper Green •About 12,000 – 14,000 cubic yards can be beneficially re-used to raise the lot. •Saves the Project over $300,000 in disposal costs. •Saves the Project over $250,000 in imported fill costs. •Green Solution – smart planning Village of Scarsdale Harcourt Woods Re-Channelization • Restore optimal stream geometry Village of Scarsdale Project Benefits Virtually no project within the 15 Bronx River watershed sub-basins reduces existing peak flow run off rates to any appreciable extent ………..until now. Fox Meadow Brook Project Benefits George Field NOW Park Revised Flood Plain (3- 4 inches precip) Cooper Green Project Benefits – Peak Flow Reductions* Peak Flow Reductions* George Field Park Sub-basin 70% reduction in peak flows Cooper Green 58% reduction in peak flows Murray Hill Major benefit is to DELAY the peak flow to the confluence point •For 3.5 inches of rain storm event (flash events and 24 –hr sustained events) Village of Scarsdale Project Benefits – Peak Flow Reductions* FMB Bronx River Sub-basin 50% (one of fifteen Bronx River sub basins) 30% reduction 25% in peak flows 0 % Peak Runoff ReductionsRunoff Peak (%) Bronx the River To 3.5” 4.5” 5.0” 6.0” 7.0” Storm Intensity (inches) Village of Scarsdale Project Benefits •If each of the fifteen Westchester County sub- watersheds that flow to the Bronx River could reduce peak flows for a 3 to 5 inch rain event by 30%, it would result in a significant reduction in flooding impacts. Fox Meadow Brook Project Benefits •Effective in reducing flooding in flash storm events as well as sustained events. •Eliminates invasive species & deteriorated trees and vegetation. •Introduces constructed wetland to George Field Park & Rain Gardens to Cooper Green. •Improves water quality. Village of Scarsdale Estimated Construction Costs Segment No. 1. George Field Park Wetland & Dry Detention $1,300,000 2. Cambridge Road Drainage Inlets, Cleaning, Televising & Lining $ 300,000 3. Cooper Green Rain Garden & Dry Detention $ 700,000 4. Open Watercourse re-channelization along Post Road $ 150,000 6. High School Parking Lot Flood Mitigation $ 600,000 7. Harcourt Woods re-channelization $ 100,000 TOTAL $3,150,000 6. Murray Hill Dry Detention Pond $ 600,000* * CONTINGENT ON LAND ACQUISITION AND DEMOLITION (ESTIMATED AT $2M-$3M) WHICH IS NOT INCLUDED IN THIS COST ESTIMATE Village of Scarsdale Project Schedule Public Bidding December 2011 Contract (s) Award February 2012 Start of Construction March/April 2012 Substantial Completion December 2012 Growing Seasons 2012-2014 Village of Scarsdale Questions? Village of Scarsdale Sheldrake Watershed 2009 Comprehensive Plan Summary SR2 Garden Rd Cushman Rd Sheldrake Rd SR- 2 – 199 acre watershed Cushman Road Culvert Fenway West Pond 2-yr flow = 124 cfs Fenway Irrigation Pond SR-3 – 271 acre watershed Murray Hill One of the most heavily flooded 3 Pond Area SR3 sub basins in the Village Cayuga Pond Fenway Irrigation pond replaced SR4 with groundwater pond Middle School 2-yr flow = 418 cfs SR-4 – 50 acre watershed Scarsdale SR5 Medical Group Outflow to New Rochelle SR-5 – 173 acre watershed 2-yr flow = 515 cfs Sheldrake FEMA Designated Flood Zones N Fenway Golf Club Fox Cayuga Meadow Pond Heathcote Bypass Source: FEMA Issued Sheldrake Flood Maps Sheldrake Watershed Aerial Fenway West Pond Murray Hill Fenway Irrigation Ponds Pond Cayuga Pond Middle School Sheldrake – SR3 Area SR-5 Murray Hill SR-3 Ponds SR-2 Middle School Fenway Irrigation Pond Cayuga Pond SR-5 SR-4 Sheldrake – Conceptual Improvements 1 SR-5 SR-3 SR-2 Middle School 2 Fenway Irrigation Pond 1 3 Cayuga Pond 3 Segment #3 – Cayuga Pond Segment #1 – Culvert improvements Segment #2 - Murray Hill 3 Pond enlargement, de-silting, fore bay on Sheldrake, Cushman and Garden de-silting to increase storage installation and improvements to Roads, Pipe/watercourse cleaning on SRcapacity.-5 Creation of fore bay in spillway withSR control-4 gate with control Garden/Cushman/Sheldrake Roads. Pond No.1 and spillway/control outlet. Cleaning/ Improvements to Greater detention capacity at Fenway gate modification for outlet. culverts and open watercourse at West Pond to increase pond storage Cleaning of open watercourse to Catherine, Cayuga, Seneca to Middle detention capacity. Cayuga Pond. School/.Quaker Center. .