September 7, 2011
Welcome – Catherine Daly Woodbury
DCR Coordination – Dan Driscoll
Project Background – Catherine Daly Woodbury
Stormwater Wetland Design and Construction Mitigation – DukeBitsko
Construction Activities, Schedule and Sequence – Tom Ritchie
Post Construction Activities and Project Benefits – Duke Bitsko
Questions
Department of Conservation and Recreation
Dan Driscoll
Cambridge DPW
Catherine Daly Woodbury
Engineering
Kleinfelder/S E A and MWH: Vin Spada, Tom Ritchie
Bioengineering Group: Duke Bitsko, Phil Rury
Construction
P. Gioioso & Sons: Joe Gioioso
Project is part of the MWRA Long-Term CSO Control Plan forAlewife Brook
LTCP will reduce CSO volume to Alewife Brook by 85%
Designed to meet the goals and objectives of DCR’s Master Planfor Alewife Reservation
CambridgePark Drive Area DrainageImprovement and StormwaterWetland Project
Part of the MWRA’s Long TermControl Plan (LTCP)for CSO ControlWill allow the sewer separation ofCAM004 (Huron A, Huron B andConcord Ave)Will result in the closure of theCAM004 CSO regulatorLTCP will reduce volume andfrequency of CSOs to the AlewifeBrook
50mg annually 7.3mg63 activations per year 7 activations
Relocate/lower existing utilitiesWetland reflaggingSurvey of Limit of Work (LOW) areaInstallation of LOW fence and erosion controlWildlife assessment
Final “polish” of stormwater before discharge intoLittle River:
Sedimentation (in forebay)Adsorption to sedimentsPhysical filtration by plantsMicrobial breakdown & plant uptake
Treatment wetlands are effective at removingsuspended solids, heavy metals and nutrients fromurban stormwaterRetains up to 10.3 acre-feet of stormwater to reducepeak flows to Little River during major storm events
Habitat Creation
Deep, emergent and high marshWet meadow, broadleaf floodplain and open waterScrub/shrub and riparian woodlandOver 115,000 new wetland plantsOver 3,800 new upland plants
Multi-use connector path (Mass DOT)Trails and boardwalks (1,600 linear feet)Overlooks (3)AmphitheatreBenches and bike racksDCR Kiosk and interpretive signage
Site Amenities
Erosion and sedimentation control
Wildlife impacts
Multi-Use Path detour and signage
BMP Devices (temporary)Sediment control basinsFlood protection bermCover crop seed mix and/or mattingCompost filter socksTurbidity curtain (Little River)
Turbidity Curtain
CompostFilterSocks
Wildlife Impact/Risk Assessment Conclusions:October start maximizes use of food resourceMinimal breeding season/migratory bird risksAvoid Little River disturbance during Alewife run
American WoodcockLicensed Wildlife Trappers were consulted:
Predicted resident wildlifewill leave work area whenclearing and grubbingcommenceRelocate wildlife outside ofthe work area
Preconstruction Wildlife ReconnaissanceSearch work area for burrows, dens, nest sitesProvide “gaps” in construction fencingSite monitoring to detect any fauna at risk
Preconstruction Rare Plant ReconnaissanceBotanist will search entire impact area
Pre Wetland ActivitiesUtilities relocation (ongoing)Species identificationErosion control and impactmitigationClearing – begins October 1Species relocation
Wetland ConstructionGrubbingEarthwork: soil excavationand bermsCover crop plantingBoardwalk andamphitheater constructionWetland soils, plantingsand seedingFinal path paving
ClearingMowerSkidder
EarthworkBulldozerExcavatorDump Trailer
Wetland Construction Start – October 2011Fall/Winter 2011-2012
Species identification/relocation; erosion controlSite clearingInstall berms and French drainsExcavate and shape Oxbow, Main Outlet and Forebay elements
Spring 2012Install timber overlook, piping and plantingsExcavate and install plantings for central area east of access road
Fall 2012Excavate remaining central area; install boardwalk and plantingsInstall amphitheaterRemove outlet barriers after vegetation is established
Spring 2013Any remaining planting
Anticipated Completion – April 2013
Fall/Winter 2011-2012Species identification and relocationErosion control and site clearingInstall berms and French drainsExcavate Oxbow, Main Outlet and Forebay areas
OXBOW
MAIN OUTLET
FOREBAY
Spring 2012Install timber overlookPlanting of Forebay, Oxbow and Main Outlet areasExcavate central wetland and begin planting
OVERLOOK
CENTRALUPLANDS/WETLANDS
Fall 2012Construct amphitheaterInstall boardwalksComplete planting of central wetland and upland areaComplete Multi Use Path
Spring 2013Completeplantings
AMPHITHEATER
BOARDWALKS
Observe plant growthReplace vegetation as neededIdentify invasive species for removal
Exclusion Fencing
Fully integrated with DCR Alewife Reservation andGreenway Master Plan:
Alewife Reservation Project Benefits
Water Quality Improvements: 3.4 acre treatment wetland, andfuture closure of the CAM004 regulatorEcological enhancements of fish and wildlife habitat qualityMitigation of invasive plant speciesImproved site amenitiesEducational and recreational opportunities
Contact InformationPrimary Contact: Catherine Daly Woodbury
[email protected] 349 4818
24-Hour Emergency ReportingCambridge DPW at 617-349-4800
DCR Primary Contact: Dan [email protected] 626 1438
Web site Informationwww.cambridgema.gov/theworks/cityprojects.aspx, underCambridgePark Drive Area Drainage Improvements andStormwater Wetland Project
Questions?