Erosion and sedimentation control Wildlife impacts Wildlife - - PowerPoint PPT Presentation

• Erosion and sedimentation control
• Wildlife impacts
• Wildlife impacts
• Multi‐Use Path detour and signage

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MWRA’s LTCP for CSO Control

• Sewer separation of CAM004

b l d b b 20 To be completed by December 2015.

• Closure of the CAM004 regulator
• Reduces volume and frequency of CSOs

to the Alewife Brook ▪ 50mg annually  7 3mg ▪ 50mg annually  7.3mg ▪ 63 activations per year  7

BMP Devices (temporary) BMP Devices (temporary) Sediment control basins Flood protection berm Cover crop seed mix and/or matting Alewife Reservation Compost filter socks/silt fences Turbidity curtain

Stormwater Stormwater wetlands provide water quality t t t th h treatment through the interaction of the water, soil and , plants.

 Sedimentation  Adsorption to Sediments  Physical filtration  Microbial breakdown  Plant Uptake

Volatilization NH3 Volatile organics

CO2, CH4

Decomposition

N2

Denitrification

Plant storage

 Plant Uptake  Extra Detention and/or

Plant uptake

Organic C

Inflow

NO3

‐

Sedimentation

xtra etention and/or Retention

Soil storage (peat) Burial

Adsorption ‐ NH4

+, metals, P, organics

(to clays, Fe / Al hydroxides,

• rganic matter)

Precipitation ‐ P (with Fe, Al, Ca) ‐ Metals (with sulfides) Metals (with sulfides)

Source: K.R. Reddy

Habitat Creation

• Deep, emergent and high marsh
• Wet meadow, broadleaf floodplain and open water
• Scrub/shrub and riparian woodland

O 115 000 tl d l t

• Over 115,000 new wetland plants
• Over 3,800 new upland plants

DCR Reservation Features

• Multi‐use connector path (Mass DOT)
• Trails and boardwalks (1,600 linear feet)
• Overlooks (3)
• Amphitheatre

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• Benches and bike racks
• DCR Kiosk and interpretive signage

b Forebay = 0.27 acres (50ft x 170ft)

Stormwater Wetland Stormwater Wetland Footprint = 3.4 acres Primary Wetland = 2.8 ac. y Peninsula = 0.2 acres Habitat Diversity Habitat Diversity High Marsh Low Marsh Low Marsh Open Water Upland Island p

• Erosion and sedimentation control
• Wildlife impacts
• Wildlife impacts
• Multi‐Use Path detour and signage

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Wildlife Impact/Risk Assessment Conclusions: Wildlife Impact/Risk Assessment Conclusions:



October start maximizes use of food resource



Minimal breeding season/migratory bird risks A id Littl Ri di t b d i Al if



Avoid Little River disturbance during Alewife run Licensed Wildlife Trappers were consulted:

American Woodcock

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• Predicted resident wildlife

will leave work area when clearing and grubbing commence

• Relocate wildlife outside of
• Relocate wildlife outside of

the work area

Preconstruction Wildlife Reconnaissance Preconstruction Wildlife Reconnaissance

 Search work area for burrows, dens, nest sites  Provide “gaps” in construction fencing  Site monitoring to detect any fauna at risk

Preconstruction Rare Plant Reconnaissance

 Botanist searched entire impact area

P W l d A i i i W tl d C t ti

 Pre Wetland Activities

• Utilities relocation
• Species identification

 Wetland Construction

• Grubbing

E h k il i

• Species identification
• Erosion control and impact

mitigation

• Earthwork: soil excavation

and berms

• Cover crop planting
• Clearing – began October 1

Cover crop planting

• Boardwalk and

amphitheater construction

• Wetland soils, plantings

and seeding Fi l th i

• Final path paving

• Fall/Winter 2011‐2012

Spring 2012 Fall 2012/Spring 2013

Alewife Reservation

 Observe plant growth  Observe plant growth  Replace vegetation as needed

d if i i i f l

 Identify invasive species for removal

E l i F i Exclusion Fencing

Alewife Reservation Project Benefits

Fully integrated with DCR Alewife Reservation and

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Greenway Master Plan:

• Water Quality Improvements: 3.4 acre treatment wetland, and

future closure of the CAM004 regulator future closure of the CAM004 regulator

• Ecological enhancements of fish and wildlife habitat quality
• Mitigation of invasive plant species

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• Improved site amenities
• Educational and recreational opportunities

Cambridge in 1777