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

cwoodbury@cambridgema.gov617 349 4818

24-Hour Emergency ReportingCambridge DPW at 617-349-4800

DCR Primary Contact: Dan DriscollDan.Driscoll@state.ma.us617 626 1438

Web site Informationwww.cambridgema.gov/theworks/cityprojects.aspx, underCambridgePark Drive Area Drainage Improvements andStormwater Wetland Project

Questions?