HomeMy WebLinkAbout260219_Yarmouth_Grove_ PPT (final)_22108A (2)Yarmouth Stormwater Project
Grove Street
Permit Hearing – February 19, 2026
April Wobst and Hannah Brown, APCC
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The Problem
Impaired Water Quality: Freshwater and Coastal
Untreated Stormwater Contributing Source to Problem
Nutrient impairment
Bacterial contamination
Why Grove Street?
Water quality improvement to Lewis Bay and Hyannis Harbor
Pavement reduction
Improve public access
Public education
Template for other ways to water
Nutrient impairment: High nutrients cause algal and cyanobacteria blooms, which leads to unsafe conditions for aquatic species and humans.
Bacterial contamination: Leads to closures of shellfish areas and public beaches
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Project Overview
Short-term Goals:
Identify locations across Yarmouth for stormwater management improvement
Advance plans for five priority sites through design and permitting to align for construction
Long-term Goals:
Improve water quality
Reduce shellfish bed closures
Funded By:
10:05-10:20
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Project Timeline
Completed 2023
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Yarmouth Stormwater Project Improving Water Quality
Presenter Name
Grove Street
Stormwater Retrofit
Public Hearing
Yarmouth Conservation Commission
MassDEP File No. SE-83-2521
February 19, 2026
*Funding for this work has been provided by Massachusetts Office of Coastal Zone Management Coastal Habitat and Water Quality Grants.
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agenda
Project Goal
Existing Conditions/Resource Areas
Proposed Conditions
Resource Area Impacts
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Project Goal
To improve coastal water quality by reducing or eliminating pollution (bacteria and nitrogen in particular) from stormwater runoff
Stormwater runoff can pick up and transfer many different kinds of pollutants. With this project we aim to address and reduce all of these but of particular concern is nitrogen and bacteria.
The treatment systems we plan to install will be specifically selected to maximize the amount of nutrients and bacteria removed from runoff. And through education and activities with
the public we aim to also reduce the amount of pollution at the source through better stormwater management practices across the community and encouraging reduction in use of fertilizers.
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10 Original
Priority Sites
Advanced 5 Sites:
HIH-3 Grove Street
MC-3 Standish Way-BUILT
MC-5 Baker Ave
PR-3/4 Lake Rd West
UBR-4 Curve Hill Road-BUILT
Optional – maybe something APCC should cover
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10 Priority Sites
2 more sets in Concept Phase:
OM-2 & OM-7 Old Main
LBPR-1 Wings Grove Beach
Optional – maybe something APCC should cover
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Site Location
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Existing Conditions
Grove Street - public way to water
Bordered by residential properties to the east and west
Evidence of erosion/accumulated sediment at end of road.
Existing Stormwater Infrastructure: a clogged leaching basin
Discharges to Hyannis Inner Harbor/Lewis Bay
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Overall Existing Conditions
Total Drainage Area = 0.33 acres
Impervious Area = 0.18 ac (55% )
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Salt Marsh (blue)
Coastal Beach (pink)
Coastal Dune (green)
35-ft, 50-ft and 100-ft Buffer Zones to Coastal Dune (yellow)
100-ft Riverfront Area (cyan)
Land Subject to Coastal Storm Flowage (LSCSF):
Flood Zone VE, EL – 13 (below red)
Flood Zone AE, EL – 11 (between red and purple)
Resource Areas
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FEMA
FIRMette
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HIH-3 Grove Street Proposed Conditions
DA1A:
Total Drainage Area = 0.32 acres
Impervious area = 0.17 ac (52% )
Proposed GSI Practice: Bioretention Area
DA1B:
Total Drainage Area = 0.01 acres
No Impervious Area
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Stormwater Design Components
Paved Drainage Flume with Embedded Stone Apron for velocity control
Sediment Forebay for pretreatment
Forebay Boulder Spillway
Bioretention Area
Overflow Boulder Spillway directing runoff towards beach
Describe how it works, and all the components – and the importance of the weirs (level surface)
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Bioretention
Paved Drainage Flume
Sediment forebay pretreatment
Forebay Spillway with boulders
Bioretention with soil and plants
Large storm runoff to Overflow Spillway with boulders
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Site Amenity Components
Educational signage
Bike rack
Reusing existing split rail fence
Sand fence
Native vegetation planting
Invasive Species Removal
Maintain access to water
Re-using split rail fencing (within the Velocity Zone)
ROMU & CEOR to remove
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Resource Areas
Salt Marsh (blue)
Coastal Beach (pink)
Coastal Dune (green)
35-ft, 50-ft and 100-ft Buffer Zones to Coastal Dune (yellow)
100-ft Riverfront Area (cyan)
Land Subject to Coastal Storm Flowage (LSCSF):
Flood Zone VE, EL – 13 (below red)
Flood Zone AE, EL – 11 (between red and purple)
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Coastal Resource Area Impacts
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Stormwater Design
Design Elements
Stormwater practice maintains low profile
Net reduction in pavement
Reusing existing split rail fencing
Discuss the velocity zone – change to design
Reusing split rail fence (repeat as necessary)
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Planting Plan
Planting Plan
Native, salt tolerant species
Dune enhancement plantings
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Resource Area Impacts
The proposed project will improve conditions:
Project components improve the ability of resource areas to perform their function to protect the interests of the state and local wetland regulations.
The project is restorative in nature and will provide an overriding public, environmental, and health benefit through the improvement of the water quality in Hyannis Inner Harbor/Lewis
Bay.
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Thank You!
Questions?
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