North Branch Park River Watershed Design Station Boards

WATERSHED CONTEXT

WATERSHED OVERVIEW

WATERSHED POPULATION

HOW MUCH OF THE WATERSHED DOES EACH MUNICIPALITY COMPRISE?

WHAT PERCENTAGE OF EACH MUNICIPALITY IS WITHIN THE NBPR WATERSHED?

STREAMS & SUBWATERSHEDS

WATERSHED AREA 28.6

BRANCH

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CONCEPT DEVELOPMENT

FLOODPLAIN & RIPARIAN CORRIDOR

The area along the North Branch Park River, which includes the floodplain, riparian area, and adjacent uplands, is a key integrating feature for green infrastructure.

Floodplain

A floodplain is the area of land next to a river or stream that is susceptible to being inundated by floodwaters. Floodplains provide important social, economic and ecological functions such as floodwater storage and movement, groundwater recharge, water quality protection (trapping of sediment and nutrients), and wildlife and fish habitat. Floodplains are also places where people, human structures, and critical transportation infrastructure can be vulnerable to disruption and damage.

The regulatory floodplain, also referred to as the flood hazard area or zone, is the flood prone area adjacent to a river or stream defined by the return period of its inundation. For example, the 100-year floodplain corresponds to the area inundated by the flood with a return period of 100 years or a 1 percent chance of occurring in any given year (1 percent Annual Exceedance Probability).

The adjacent figure shows the 100-year and 500-year regulatory floodplains, as mapped by the Federal Emergency Management Agency (FEMA), for the North Branch Park River subwatershed.

WOODED FLOODPLAIN AND RIPARIAN AREA WOODED FLOODPLAIN

CONCEPT DEVELOPMENT

FLOODPLAIN & RIPARIAN CORRIDOR

Riparian Area & Riparian Corridor

Riparian areas are the transition zone between terrestrial and aquatic systems and typically include streambanks, floodplains, wetlands and other systems adjacent to rivers and streams. Riparian areas characteristically have high water tables and are subject to periodic flooding. Healthy riparian areas (i.e., characterized by stable, healthy vegetation) have high ecological diversity, can maintain or improve water quality, and have both recreational and economic benefits.

The riparian corridor encompasses riparian areas, as well as adjacent upland areas needed to protect or restore riparian function. For example, steep erodible slopes that could adversely affect the riparian area or the stream are included in the riparian corridor (see adjacent figure for steep slope areas along the North Branch Park River).

The management goal for riparian corridors is to maintain or restore the area to a vegetated condition to help filter pollutants and to protect riparian habitat and species. Mitigation measures can be located within the riparian corridor to protect water quality and riparian values.

GREEN INFRASTRUCTURE

What is Green Infrastructure?

Green Infrastructure (GI) refers to natural and man-made landscapes and practices that reduce stormwater runoff using vegetation, soils, and natural processes to manage water and create healthier urban and suburban environments. These practices capture, manage, and/or reuse rainfall close to where it falls, reducing stormwater runoff and keeping it out of drainage systems, combined sewer systems, and receiving waters.

Examples of natural green infrastructure include forests, meadows, and floodplains and land conservation strategies to preserve these features in a natural or undeveloped state. Examples of man-made green infrastructure include Green Stormwater Infrastructure (GSI) for managing

stormwater runoff at the site or neighborhood scale, such as bioswales, rain gardens, green roofs, and rainwater harvesting, as well as other types of designed green infrastructure such as urban tree canopy, floodplain and riparian corridor restoration and conservation, and urban rewilding.

The Benefits of Green Infrastructure

In addition to reducing runoff and improving water quality, green infrastructure has been shown to provide many other social and economic benefits as highlighted in the following graphic.

Other Natural and Designed Green Infrastructure

The multiple benefits of green infrastructure (Source: Carbon180).

Green Stormwater Infrastructure (GSI)

Infiltration basins

Bioretention systems

Bioretention Planters Parking Lot Bioretention

Bioretention & Walking Trails Rain Gardens

Roadside Bioswales Green Streets

Urban Tree CanopySmall Urban Forests & Urban Rewilding

Riparian & Floodplain Restoration

CONCEPT DEVELOPMENT

FLOODPLAIN & RIPARIAN CORRIDOR

DESIGN STRATEGIES

Riparian & Floodplain Restoration

Restore riparian areas and floodplains currently occupied by parking lots and other flood prone development to re-establish natural ecological system processes and functions (water quality, habitat, flood reduction, etc.). Restoration of these areas would involve converting portions of the existing parking lots to a more natural condition and function by removing the man-made infrastructure, removing non-native vegetation, amending the soils, and planting native trees and shrubs. Other modifications to the streambanks, riparian area, and floodplain may be warranted to re-connect the stream to its floodplain and restore lost hydrologic function and habitat.

Land Conservation

Protect or preserve land in a natural or undeveloped state through acquisition and/or conservation easement or other type of conservation restriction. Target existing undeveloped parcels along riparian corridors and in headwater areas, as well as areas proposed for riparian and floodplain restoration.

Challenges

• Loss of existing parking and future development potential

• Voluntary cooperation of property owners

• Strategies and incentives to reduce parking and other impervious cover such as shared parking, stormwater user fee and credit system, and structured parking

LAND CONSERVATION OF FLOODPLAIN, RIPARIAN CORRIDOR, AND WOODED STEEP SLOPES

FLOODPLAIN AND RIPARIAN CORRIDOR, INCLUDING WOODED STEEP SLOPES

RIPARIAN/FLOODPLAIN

FLOODPLAIN

RESTORATION OF EXISTING PARKING LOTS

RESTORATION OF EXISTING PARKING LOTS

CONCEPT DEVELOPMENT

IMPERVIOUS SURFACES & POLLUTED RUNOFF

DESIGN STRATEGIES

Green Stormwater Infrastructure

Retrofit existing impervious surfaces with bioswales, rain gardens, infiltration systems, green roofs, and other green stormwater infrastructure (GSI) practices. Numerous GSI retrofit opportunities exist on public and institutional properties within the North Branch Park River subwatershed including parking lots, schoolyards, and along roads (green streets). Opportunities also exist for installation of larger subsurface storage and infiltration systems below athletic fields and parking lots.

Several areas of the watershed with combined sewers are slated for future sewer separation (e.g., Granby Street and Blue Hills neighborhood), creating the opportunity to incorporate GSI into the right-of-way (green streets) as part of the sewer separation and GSI treatment of new separated stormwater discharges that will serve these areas.

Challenges

• Voluntary cooperation of property owners

• Combined sewers in a large portion of the subwatershed. MDC currently prohibits the use of open-bottom stormwater infiltration systems in combined sewer areas due to concerns about groundwater potentially entering the combined sewer system through stormwater infiltration systems.

• Portions of the watershed are underlain by soils with low infiltration capacity (clay soils) and a high groundwater table, which are challenging site conditions for implementation of infiltration-based GSI. This underscores the importance of careful GSI selection and design.

• Strategies and incentives to reduce impervious cover such as stormwater user fee and credit system

GREEN STREETS

GREEN STORMWATER INFRASTRUCTURE IN PARKING LOTS

CONCEPT DEVELOPMENT

IMPROVED ECOLOGICAL & RECREATIONAL CONNECTIVITY

DESIGN STRATEGIES

Walking Paths and Trails

Create walking paths and trails within restored riparian/floodplain areas to connect area schools, institutional facilities, and landscapes to the river corridor and to the proposed Hartline multi-use trail. Boardwalks could be used within the restored floodplain to elevate the walking paths above the flood elevation.

Existing sidewalks, as well as new side paths and bicycle lanes added along existing roads, could provide connections between the walking path/trail network and existing or proposed green spaces in the watershed. The proposed walking paths/trails and green streets can also serve as cooling corridors by providing shaded routes for walking and bicycling.

River & Stream Crossings

There are numerous road crossings (culverts and bridges) of the North Branch Park River and its tributaries. These crossings have the potential to restrict wildlife (terrestrial and aquatic) passage, restrict flood flows and act as choke points for trees and debris, and contribute to erosion and degraded water quality. The road-stream crossings in the watershed should be evaluated for potential upgrade/replacement and related stream restoration.

Challenges

• Voluntary cooperation of property owners

• Public concern over proposed walking paths/ trails

• Engineering and fluvial geomorphic evaluation of river and road-stream crossings

EVALUATE RIVER CROSSING FOR REPLACEMENT

WALKING PATHS IN RESTORATION AREAS

TRAIL CONNECTIONS

FOCUS AREA CONCEPTS

FARMINGTON AVENUE TO ASYLUM AVENUE

CONNECTICUT MUSEUM OF CULTURE AND HISTORY

CLASSICAL MAGNET SCHOOL

CONNECTICUT COMMUNITY COLLEGES

POLLINATOR GARDEN

FLOODPLAIN RESTORATION WITHIN EXISTING PARKING LOTS

SUBSURFACE STORMWATER STORAGE

HARTFORD INTERNATIONAL UNIVERSITY FOR RELIGION AND PEACE

GREEN STORMWATER INFRASTRUCTURE (TYP)

GREEN STREETS (TYP)

LAND CONSERVATION

CSO N-10

CSO N-9

FOCUS AREA CONCEPTS

ASYLUM AVENUE TO HOMESTEAD AVENUE

FLOODPLAIN RESTORATION WITHIN EXISTING PARKING LOTS

GOODWIN CIRCLE

WOODSIDE CIRCLE

SUBSURFACE

STORMWATER STORAGE

LAND CONSERVATION

CONNECTICUT MUSEUM OF CULTURE AND HISTORY

EVALUATE EXISTING STREAM CROSSING (TYP)

CLASSICAL MAGNET SCHOOL

CONNECTICUT COMMUNITY COLLEGES

CSO N-9

POLLINATOR GARDEN

CSO N-10

FOCUS AREA CONCEPTS

EVALUATE EXISTING STREAM CROSSING (TYP)

HOMESTEAD AVENUE & GOODWIN’S WILD

FLOODPLAIN RESTORATION

PROPOSED SIDE PATH

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

EVERSOURCE ELECTRICAL SUBSTATION

GREEN STORMWATER INFRASTRUCTURE WITH BROWNFIELD REDEVELOPMENT

FLOODPLAIN RESTORATION WITH FUTURE SITE REDEVELOPMENT

LAND CONSERVATION

FUTURE HARTLINE MULTIUSE TRAIL

GREEN STREET SCARBOROUGH STREET

GOODWIN’S WILD (OLD GROWTH FOREST)

FOCUS AREA CONCEPTS

UPPER ALBANY NEIGHBORHOOD

HANDEL PERFORMING ARTS CENTER AT UNIVERSITY OF HARTFORD

GSI WITHIN PARKING LOTS (TYP)

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

GREEN STORMWATER INFRASTRUCTURE WITH BROWNFIELD REDEVELOPMENT

FUTURE HARTLINE MULTIUSE TRAIL

GSI WITHIN PARKING LOTS (TYP)

ALBANY BRANCH

FOCUS AREA CONCEPTS

NORTH OF ALBANY AVENUE & MARK

TWAIN DRIVE

WALKING TRAIL

UNIVERSITY HIGH SCHOOL OF SCIENCE & ENGINEERING

UNIVERSITY OF HARTFORD MAGNET SCHOOL

GSI WITHIN PARKING LOTS (TYP)

LAND CONSERVATION

FISHER MONTESSORI MAGNET SCHOOL

GREEN STREET ALONG MARK TWAIN DRIVE ONGOING PHASED REDEVELOPMENT WITH LID/GSI

FUTURE HARTLINE MULTI-USE TRAIL

EVALUATE EXISTING RIVER CROSSING (TYP)

FOCUS AREA CONCEPTS

LAND CONSERVATION –RIPARIAN AREA OF TRIBUTARY TO NORTH BRANCH PARK RIVER

CRONIN PLAYGROUND & BLUE HILLS

NEIGHBORHOOD

GSI AT EXISTING STORM DRAIN OUTFALL (TYP)

GSI WITHIN PARKING LOTS (TYP)

GSI WITHIN PARKING LOT ISLANDS AND EDGES (TYP)

GREEN STREETS IN FUTURE SEWER SEPARATION AREA (TYP)

SUBSURFACE STORAGE SYSTEM BENEATH ATHLETIC FIELDS TO MANAGE STORMWATER FROM FUTURE SEPARATE STORM DRAINAGE SYSTEM

ST

LYME

FOCUS AREA CONCEPTS

UNIVERSITY OF HARTFORD –SOUTH

EVALUATE EXISTING STREAM CROSSING (TYP)

FLOODPLAIN RESTORATION OF UHART PARKING LOT

FOCUS AREA CONCEPTS

UNIVERSITY OF HARTFORD –NORTH

EVALUATE EXISTING STREAM CROSSING (TYP)

FUTURE HARTLINE MULTI-USE TRAIL

GSI WITHIN PARKING LOT (TYP)

GSI WITHIN PARKING LOT (TYP)

GREEN STREET (TYP)

FOCUS AREA CONCEPTS

ELIZABETH PARK

GSI ALONG PARK ROADS AND PARKING LOTS (TYP) ROADS AND IN

ENHANCED POND BUFFER

ELIZABETH PARK ROSE GARDEN

INTEGRATE GSI INTO FUTURE PARK IMPROVEMENTS CONSISTENT WITH UPDATED MASTER PLAN FOR ELIZABETH PARK EAST

ELIZABETH PARK EAST

ELIZABETH PARK POND

FOCUS AREA CONCEPTS

SOUTH OF FARMINGTON AVENUE

CLEMENS PLACE

SHEPHERD

HARRIET BEECHER STOWE CENTER GREEN STORMWATER INFRASTRUCTURE (TYP)

GREEN ROOF (TYP)

ROOF (TYP)

NORTH BRANCH

NORTH BRANCH

GREEN STREETS (TYP)