Recommended Actions Summary Town of South Kingstown, RI

Wood-Pawcatuck Watershed Flood Resiliency Management Plan August 2017 Recommended Actions Summary Town of South Kingstown, RI

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - South Kingstown damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 46% of town within watershed • Includes portions of the Pawcatuck, the watershed municipalities and partner agencies, has developed Chickasheen, Chipuxet, Usquepaug, a watershed-based management plan to enhance the resiliency and Queen Rivers and their of the watershed communities to future flooding and protect river watersheds and stream ecosystems, including water quality and habitat. The • 44 stream crossings assessed following is a summary of key findings and recommendations of • 6 dams assessed the watershed plan for the Town of South Kingstown.

Road Stream Crossings Dams • 18 crossings are hydraulically undersized • 1 significant hazard dam and 5 low hazard dams • 16 crossings have high geomorphic vulnerability • All of the dams are deteriorating or in disrepair • 5 crossings have high flood impact potential • Glen Rock Reservoir Dam, the downstream-most • 27 crossings limit or restrict aquatic passage dam on the Usquepaug River, completely prevents fish passage to the Usquepaug River Recommendations: Recommendations: • Replace and upgrade priority crossings (see table below) to meet flood resilience and aquatic Glen Rock Reservoir Dam (Usquepaug River) organism passage (AOP) goals • Repair deteriorating structure • Consider other upstream and downstream • Install aquatic organism passage structure to crossings and dams on the same river system permit fish passage to the Usquepaug • In general, replace downstream crossings first Glen Rock Upper, Middle, and Lower Pond Dams • Perform site-specific data collection, geotechnical (Glen Rock Brook) evaluation, hydrologic and hydraulic evaluation, • Consider removal if supported by the owner and structure type evaluation to support design Great Swamp Goose Marsh Dam (Pawcatuck Priority Stream Crossings River) Road Stream Crossing Type • Repair dam • Maintain impoundment within Great Swamp 36” Concrete Liberty Road Unnamed Circular Conduit Management Area (provides bird habitat) South County Double 28” Concrete Unnamed Yawgoo Pond Dam (Chickasheen River) Trail Circular Conduit Worden Pond • Construct a small rock ramp or nature-like fishway Triple 12” HDPE Family Alewife Brook up the spillway to allow for fish passage Circular Conduit Campground 24” CMP Circular Ministerial Road Alewife Brook Conduit 12” Concrete Ministerial Road Mink Brook Circular Conduit Peckham Farm 20” Concrete Unnamed Road Circular Conduit Triple 36”H x 48”W Walking Path Unnamed Concrete Box Culvert 24” Concrete Plains Road Unnamed Circular Conduit 24” Concrete Flagg Road Unnamed Circular Conduit 30” Concrete Glen Rock Road Unnamed Circular Conduit Curtis Corner White Horn No data Road Brook Glen Rock Reservoir Dam

Project funding was provided by the National Fish and Wildlife Foundation Hurricane Sandy Coastal Resiliency Competitive Grant Program Wood-Pawcatuck Watershed Flood Resiliency Management Plan August 2017

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed field geomorphic assessment was infrastructure (GI) retrofit sites was performed performed for approximately 40 miles of rivers and within the Wood-Pawcatuck watershed. When streams in the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. While field geomorphic assessments Sites Identified for GI Retrofits: were not conducted within South Kingstown, these • Tennis Courts at Boss Arena, URI recommendations apply in the town and throughout o Install rain gardens in the lawn between the the watershed. arena and tennis courts Recommendations: o Cost: $44,000 • Parking lot at Boss Arena, URI • Protect existing wetlands as well as stream o Underground infiltration in main parking lot connections to wetlands and floodplains o Cost: $557,000 • Remove floodplain constraints, such as levees or berms, where possible Courthouse Center for the Arts • • Protect and enhance riparian buffers Retrofit drainage swale and parking lot with o • Install log jams in select locations along the stream bioretention basins corridor to protect banks, create habitat, and re- Cost: $121,000 o form meanders (where human conflicts with • Tuckertown Park meander formation are not present) o Bioretention • Avoid or limit alterations that will straighten or o Cost: $169,000 channelize stream channels • West Kingston Elementary School • Consider removing bank armoring where possible o Bioretention and underground infiltration once a protected river corridor is established o Cost: $122,000

View of a typical bioretention cell with mature plantings. Conceptual view of a typical floodplain cross section.

Land Use Policy and Regulations • Consider adopting a No Adverse Impact (NAI) Floodplain Management policy Municipal land use policies and regulations can help • Amend zoning ordinance to strengthen flood communities become more resilient to flooding by: management standards • Preserving undeveloped land • Consider implementing fluvial erosion hazard zoning Siting development in locations less vulnerable to • to address riverine erosion hazards flooding, and • Amend zoning ordinance and subdivision regulations Promoting designs that reduce runoff and are less • to require all development projects to comply with LID likely to be damaged in a flood standards and the Rhode Island Stormwater Design and Installation Standards Manual Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts – Charlestown damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 66% of town within watershed • Includes portions of the Pawcatuck the watershed municipalities and partner agencies, has developed River (Charlestown’s northern a watershed-based management plan to enhance the resiliency boundary), smaller tributaries, of the watershed communities to future flooding and protect river freshwater ponds, and their and stream ecosystems, including water quality and habitat. The associated watersheds following is a summary of key findings and recommendations of • 27 stream crossings assessed • 1 dam assessed the watershed plan for the Town of Charlestown.

Road Stream Crossings Dams • 7 crossings are hydraulically undersized • A single low hazard dam – Burdickville Dam – was • 12 crossings have high geomorphic vulnerability assessed in Charlestown, on the Charlestown/ • 11 crossings have high flood impact potential Hopkinton border • 9 crossings limit or restrict aquatic passage Recommendations: Recommendations: Burdickville Dam (Pawcatuck River) • Replace and upgrade priority crossings (see table • Consider dam removal below) to meet flood resilience and aquatic • Burdickville Dam has been partially breached but organism passage (AOP) goals may currently prevent passage of some fish • Consider other upstream and downstream species, such as shad crossings and dams on the same river system • The impoundment does not appear to support • In general, replace downstream crossings first any active uses • Perform site-specific data collection, geotechnical evaluation, hydrologic and hydraulic evaluation, and structure type evaluation to support design Priority Stream Crossings (Sorted in Order of Priority) Road Stream Crossing Type Burlingame State Double 24” Park- Unnamed Concrete Circular Management Area Conduit Burlingame State 12” Concrete Park- Unnamed Circular Conduit Management Area 12” Concrete Narragansett Trail Unnamed Circular Conduit Burdickville Dam 38” and 12” Buckeye Brook Poquiant Concrete Circular Road Brook Conduit (2 total) Shumankanuac 36” Concrete Unnamed Hill Road Circular Conduit 12” Concrete Saw Mill Road Unnamed Circular Conduit Kings Factory Pawcatuck 57’W x 9’H Concrete Road River Bridge 67.5’W Concrete Pawcatuck Shannock Road Bridge; openings River 3.3’H 7.8’H Old Shannock Pawcatuck 48’W X 9.4’H Dual concrete culverts at a high priority stream Road River Concrete Bridge crossing in Burlingame State Park Management Area

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Vin Gormley Trailhead Parking o Retrofit parking lot with underground • Remove granite blocks confining channel infiltration and a bioretention basin downstream of Route 112 to allow floodplain o Cost: $123,000 access; use granite blocks to build in-stream • St. Mary’s Catholic Church habitat structures o Install a bioretention practice in the grassed • Protect wetlands, including Indian Cedar Swamp, island at the Carolina Back Road and Old as well as stream connections to wetlands and Carolina Back Road intersection floodplains o Cost: $143,000 • Install log jams in select locations along the stream corridor to protect banks, create habitat, and re- form meanders

Typical installation of underground infiltration system below an existing parking lot.

Granite-lined, straightened mill-race channel with restricted floodplain access, located downstream of Route 112. View of a typical bioretention cell with mature plantings.

Land Use Policy and Regulations • Consider adopting a No Adverse Impact (NAI) Floodplain Management policy Municipal land use policies and regulations can help • Amend zoning ordinance to strengthen flood communities become more resilient to flooding by: management standards • Preserving undeveloped land,land • Consider implementing fluvial erosion hazard zoning Siting development in locations less vulnerable to • to address riverine erosion hazards flooding, and • Consider amendments to the existing Promoting designs that reduce runoff and are less • conservation/cluster development provisions in the likely to be damaged in a flood.flood zoning ordinance and subdivision regulations to strengthen flood management provisions Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Exeter damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 91% of town within watershed • Includes portions of the Chipuxet, the watershed municipalities and partner agencies, has developed Chickasheen, Beaver, Usquepaug, a watershed-based management plan to enhance the resiliency Wood, and Queen Rivers and their of the watershed communities to future flooding and protect river watersheds and stream ecosystems, including water quality and habitat. The • 63 stream crossings assessed following is a summary of key findings and recommendations of • 11 dams assessed the watershed plan for the Town of Exeter.

Road Stream Crossings Dams • 25 crossings are hydraulically undersized • 5 high hazard dams, 1 significant hazard dam, and • 30 crossings have high geomorphic vulnerability 5 low hazard dams • 6 crossings have high flood impact potential • Several dams provide recreational or other uses • 9 crossings limit or restrict aquatic passage and are undergoing or were recently repaired • Several dams are recommended for repair or Recommendations: removal due to poor condition and lack of • Replace and upgrade priority crossings (see table maintenance below) to meet flood resilience and aquatic Recommendations: organism passage (AOP) goals • Consider other upstream and downstream Breakheart Pond Dam (Breakheart Brook) crossings and dams on the same river system • Located within Arcadia Management Area • In general, replace downstream crossings first • Downstream watercourse has obstructions to fish • Perform site-specific data collection, geotechnical passage evaluation, hydrologic and hydraulic evaluation, • Dam is in poor condition and repairs are therefore and structure type evaluation to support design recommended Priority Stream Crossings Browning Mill Pond Dam (Roaring Brook) • RIDEM owns the dam and operates a hatchery Road Stream Crossing Type downstream 36” Concrete Deer Brook Lane Unnamed • Browning Mill Pond has significant public Circular Conduit 48” and 24”” recreational value Queens Fort Tarbox Drive Concrete Circular • Repairs are recommended for this deteriorating Brook Conduit (Total 2) dam 12” Concrete Mail Road Unnamed Circular Conduit Edward’s Pond Dam (Queen River) 24” Concrete • Owned by Exeter Country Club Purgatory Road Unnamed Circular Conduit • No apparent active uses of impoundment Chipuxet 5.3’ x 5.9’ Concrete Wolf Rocks Road • Consider dam removal River Box Culvert Yawgoo Valley Chipuxet Triple 48” Concrete Road River Circular Conduit William Reynolds 12” HDPE Circular Unnamed Road Conduit Triple 18” HDPE Liberty Road Unnamed Circular Conduit Chickasheen South Country Brook, Mud Multiple crossings Trail* Brook, Unnamed Roaring Triple 48” Concrete Summit Road* Brook Circular Conduit Breakheart *These crossings were not scored as high priority, but flooding has been reported at these locations. Pond Dam

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Exeter Town Animal Shelter o Install bioretention along the northern Arcadia Management Area south of Ten Rod Road roadside of South Country Trail to treat (Upper Wood River) approximately one quarter mile of roadway • Add wood cover structures along river banks o Cost: $107,000 (a.k.a. marginal wood cover) and wood to river to encourage meander formation and sediment Exeter Town Hall • storage within artificially straightened channel Bioretention and rain garden at parking lot o • Area is popular for fly fishing Cost: $103,000 o • Area is owned and managed by the Wood- • Browning Mill Pond Parking Access Pawcatuck Watershed Association o Bioretention and forested buffer to protect adjacent Browning Mill Pond o Regrade and till parking lot to alleviate some erosional issues and improve infiltration o Cost: $32,000

Typical rain garden detail. Straightened river channel and old bridge abutments

Land Use Policy and Regulations • The Hazard Mitigation Plan is due to be updated and should address flood-prone areas identified during the Municipal land use policies and regulations can help 2010 flood and subsequent flood events, including communities become more resilient to flooding by: street flooding identified as an issue in 2010 • Preserving undeveloped land • Consider adopting a No Adverse Impact (NAI) Siting development in locations less vulnerable to • Floodplain Management policy flooding, and • Amend zoning ordinance to strengthen flood Promoting designs that reduce runoff and are less • management standards likely to be damaged in a flood • Consider implementing fluvial erosion hazard zoning to address riverine erosion hazards Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Hopkinton damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 100% of town within watershed • Includes portions of the Wood, the watershed municipalities and partner agencies, has developed Ashaway, and Pawcatuck Rivers a watershed-based management plan to enhance the resiliency and their watersheds of the watershed communities to future flooding and protect river • 83 stream crossings assessed and stream ecosystems, including water quality and habitat. The • 19 dams assessed within the Town; following is a summary of key findings and recommendations of 6 dams assessed that lie on the border between Hopkinton and the watershed plan for the Town of Hopkinton. adjacent towns (25 dams total)

Road Stream Crossings Dams • 21 crossings are hydraulically undersized • 3 high hazard dams, 8 significant hazard dams, • 35 crossings have high geomorphic vulnerability and 14 low hazard dams • 32 crossings have high flood impact potential • 8 dams are considered high priority • 47 crossings limit or restrict aquatic passage • 6 of the dams assessed lie on the border of Hopkinton and either Richmond or Charlestown Recommendations: • Condition, purpose, and level of community use • Replace and upgrade priority crossings (see table vary widely between dams below) to meet flood resilience and aquatic Recommendations: organism passage (AOP) goals • Consider other upstream and downstream Consider Dam Repair– High Priority: crossings and dams on the same river system • Harris Pond Dam (Tomaquag Brook Tributary) • In general, replace downstream crossings first • Wyoming Pond Upper Dam (Wood River) • Perform site-specific data collection, geotechnical Consider Dam Removal – High Priority: evaluation, hydrologic and hydraulic evaluation, • Alton Pond Dam (Wood River) and structure type evaluation to support design • Ashaway Line Pond Dam (Ashaway River), Ashaway Mill Pond Dam (Ashaway River), and Priority Stream Crossings Bethel Pond Dam (Ashaway River) (collectively Road Stream Crossing Type consider removal of all 3 dams) 36” HDPE Circular Vuono Road Unnamed • Ashville Pond Dam (Blue Pond Brook) Conduit • Potter Hill Dam (Pawcatuck River) 12” Concrete Woodville Road Unnamed Circular Conduit 18” Concrete Woodville Alton Circular Conduit and Unnamed Road 18” CMP Circular Conduit 30”W x 24”H Stone Nooseneck Hill Unnamed Masonry Box Road Culvert 48”W x 48”H Tomaquag Road Unnamed Concrete Box Culvert Parmenter Four (4) 24” CMP Clarks Falls Road Brook Circular Conduits Harningstuns Double 24” Concrete Unnamed Crossing Circular Conduit 123’W x 8’H Woodville Road Wood River Concrete Bridge Triple 36” Concrete Sawmill Road Brushy Brook Circular Conduit Concrete Bridge – Woodville Road Unnamed No Dimension Data Potter Hill Dam

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Hopkinton Recreation Department o Linear bioretention practice along roadway • Protect dynamic reaches with high quality habitat, o Cost: $72,000 located along the Ashaway River, from encroachment by future development Trinity Lutheran Church • • Enhance meander development in artificially Bioretention and rain gardens o straightened channels along the Lower Wood and Cost: $61,000 o Ashaway Rivers to slow flows, increase flood • U.S. Post Office (Ashaway, RI) storage, and conserve or improve habitat o Underground infiltration under public roads • Coordinate floodplain restoration along the Lower o Cost: $282,000 Wood River with site remediation of former • Chariho Little League Charbert Facility site o Rain gardens adjacent to parking areas • Breach and/or remove confining berm o Cost: $39,000 downstream of Bradford Dam to allow floodplain • Ashaway Elementary School access during high flows and thereby increase o Underground infiltration and bioretention flood storage and slow flood flows o Cost: $229,000

View of a typical bioretention cell or rain View of straightened channel along Ashaway River, with garden with mature plantings limited habitat or flood storage

Land Use Policy and Regulations • Consider adopting a No Adverse Impact (NAI) Floodplain Management policy Municipal land use policies and regulations can help • Amend zoning ordinance to strengthen flood communities become more resilient to flooding by: management standards • Preserving undeveloped land • Consider implementing fluvial erosion hazard zoning Siting development in locations less vulnerable to • to address riverine erosion hazards flooding, and • Consider amendments to the existing Promoting designs that reduce runoff and are less • conservation/cluster development provisions in the likely to be damaged in a flood zoning ordinance and subdivision regulations to strengthen flood management provisions Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - North damages, as evidenced by the devastating flooding that occurred in Kingstown 2010. The Wood-Pawcatuck Watershed Association, working with the watershed municipalities and partner agencies, has developed • 7.3% of town within watershed a watershed-based management plan to enhance the resiliency • Includes portions of the Chipuxet River and its watershed of the watershed communities to future flooding and protect river • 6 stream crossings assessed and stream ecosystems, including water quality and habitat. The • 2 dams assessed following is a summary of key findings and recommendations of the watershed plan for the Town of North Kingstown.

Road Stream Crossings Dams • 1 crossing is hydraulically undersized • 2 high hazard dams • 1 crossing has high geomorphic vulnerability • All 6 crossings have medium flood impact Recommendations: potential Slocum Road Upper Dam (Chipuxet River • 4 crossings limit or restrict aquatic passage Tributary) Recommendations: • NOVs were issued in 2011 and 2012; owner indicated that repairs were made but DEM has not • Replace and upgrade priority crossings (see table confirmed below) to meet flood resilience and aquatic • Impoundment supports limited recreational use organism passage (AOP) goals • Dam removal should be considered if owner is • Consider other upstream and downstream amenable crossings and dams on the same river system • Maintain if owner is not amenable to removal In general, replace downstream crossings first • Slocum Woods Dam (Chipuxet River Tributary) • Perform site-specific data collection, geotechnical • Dam was in good condition in 2013 (last evaluation, hydrologic and hydraulic evaluation, documented inspection) and structure type evaluation to support design • Dam is owned by Slocum Woods Homeowners Association and is used for recreational purposes Priority Stream Crossings • The impoundment appears to be used for (Sorted in Order of Priority) irrigation for turf farming operations (Sodco) • No action beyond maintenance is recommended Road Stream Crossing Type for this dam; this recommendation is low priority

Drainage 24” Concrete Kayla Ricci Way Ditch Circular Conduit 3.5’W x 1.5’H Sylvan Court Unnamed Concrete Box Culvert

Five (5) 24” Concrete Explorer Drive Unnamed Circular Conduits

Double 6’W x 3’H Indian Corner Chipuxet Concrete Box Road River Culvert 24” Concrete Glen Hill Road Unnamed Circular Conduit 10.5’W x 2.5’H Slocum Road Unnamed Concrete Box Culvert Slocum Road Upper Dam

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. No site-specific GI retrofit concepts were developed Recommendations: for North Kingstown due to the town’s small land area within the Wood-Pawcatuck watershed and the Between Slocum Reservoir Dam and area limited scope of the GI assessment. The Town downstream of Railroad Road (Chipuxet River) should incorporate GI approaches into municipal • Encourage riparian plantings along the left bank of stormwater infrastructure planning and capital the river where residential properties abut the improvement plans to address drainage, flooding, channel, to reduce risk of erosion and promote and water quality priorities including MS4 Permit high quality habitat requirements, both within and outside of the Wood- Pawcatuck watershed. GI can be implemented on General Recommendation: Protect and enhance public sites including municipal parking lots and floodplains, wetlands, and riparian buffers in order to within the public right-of-way. reduce flood impacts and improve habitat.

Proposed area of riparian plantings where residential Rendering of a typical bioretention area properties are located on the left bank of the Chipuxet River

Land Use Policy and Regulations total watershed area and less than 10 percent of the community’s land area is within the Wood-Pawcatuck Municipal land use policies and regulations can help watershed. General recommendations that apply to communities become more resilient to flooding by: North Kingstown include: • Preserving undeveloped land • Siting development in locations less vulnerable to • Consider adopting a No Adverse Impact (NAI) flooding, and Floodplain Management policy • Promoting designs that reduce runoff and are less • Amend zoning ordinance to strengthen flood likely to be damaged in a flood management standards • Consider implementing fluvial erosion hazard zoning Recommendations: to address riverine erosion hazards • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. North Kingstown was excluded from • Implement road stream crossing standards for new the review since it comprises 1 percent or less of the and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - North damages, as evidenced by the devastating flooding that occurred in Stonington 2010. The Wood-Pawcatuck Watershed Association, working with the watershed municipalities and partner agencies, has developed • 70% of town within watershed a watershed-based management plan to enhance the resiliency • Includes portions of the Green Fall/Ashaway, Shunock, Pawcatuck of the watershed communities to future flooding and protect river Rivers, Wyassup Brook, and their and stream ecosystems, including water quality and habitat. The watersheds following is a summary of key findings and recommendations of • 63 stream crossings assessed the watershed plan for the Town of North Stonington. • 3 dams assessed

Road Stream Crossings Dams • 27 crossings are hydraulically undersized • 1 significant hazard dam and 2 low hazard dams • 29 crossings have high geomorphic vulnerability • 11 crossings have high flood impact potential Recommendations: • 43 crossings limit or restrict aquatic passage Green River Pond Dam (Green Fall River Recommendations: Tributary) • Consider formalizing breach and replacing • Replace and upgrade priority crossings (see table downstream culvert below) to meet flood resilience and aquatic • The dam has not been maintained and is partially organism passage (AOP) goals breached; current uses are unknown • Consider other upstream and downstream • The culvert downstream of this impoundment is crossings and dams on the same river system likely undersized and contributing to backwater • In general, replace downstream crossings first flooding Perform site-specific data collection, geotechnical • Lewis Pond Dam (Pawcatuck River Tributary) evaluation, hydrologic and hydraulic evaluation, • Consider dam removal and structure type evaluation to support design • Current uses are unknown; owner may use impoundment as a cattle watering hole Priority Stream Crossings Spaulding Pond Dam (Wyassup Brook) Road Stream Crossing Type • Consider dam removal 24” CMP Circular • The impoundment supports recreational uses State Highway 49 Unnamed Conduit • Once the dams on the Ashaway River are 12” HDPE Circular Loin Hill Road Unnamed removed, removal of this dam would become a Conduit higher priority Shunnock 11’W x 7’H Stone Main Street River Masonry Bridge 18” Concrete Mains Crossing Unnamed Circular Conduit Chester Main 42” CMP Circular Unnamed Road Conduit 30” CMP Circular Wyassup Road Unnamed Conduit Double 24” CMP Wyassup Road Unnamed Circular Conduits Grindstone Hill Wyassup Double 42” CMP Road Brook Circular Conduit Yawbux Valley 24” CMP Circular Unnamed Road Conduit Double 24” Concrete Pine Woods Glade Brook Circular Conduit + Road Single 5’W X3’H CMP *These crossings were not scored as high priority but flooding has Reutemann Double 24” Concrete been reported at these locationsUnnamed Road Circular Conduit Spaulding Pond Dam

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Wheeler High School o Install two bioretention basins at the front of Upstream of Puttker Road to confluence with the building Shingle Mill Pond Brook (Green Fall River) o Cost: $81,000 • Protect corridor from encroachment by development to protect valuable archaeological Wheeler Library • sites and areas with good habitat potential Install two bioretention basins to treat runoff o • Install log jams along channel margins to from the parking area, roof, and driveway encourage meander formation downstream of Cost: $53,000 o Puttker Road and thereby reduce flood impacts • North Stonington Elementary and Administration o Install multiple bioretention areas within parking lot islands and adjacent to administration building o Cost: $212,000

Typical rain garden detail. Straightened channel downstream of Puttker Road

Land Use Policy and Regulations • Consider adopting a No Adverse Impact (NAI) Floodplain Management policy Municipal land use policies and regulations can help • Amend zoning regulations to strengthen flood communities become more resilient to flooding by: management standards • Preserving undeveloped land • Consider implementing fluvial erosion hazard zoning Siting development in locations less vulnerable to • to address riverine erosion hazards flooding, and • Consider amendments to the existing Promoting designs that reduce runoff and are less • conservation/cluster development provisions in the likely to be damaged in a flood zoning and subdivision regulations to strengthen flood management provisions Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Richmond damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 100% of town within watershed • Includes portions of the Wood, the watershed municipalities and partner agencies, has developed Beaver, Pawcatuck, Usquepaug, a watershed-based management plan to enhance the resiliency and Queen Rivers and their of the watershed communities to future flooding and protect river watersheds and stream ecosystems, including water quality and habitat. The • 61 stream crossings assessed following is a summary of key findings and recommendations of • 10 dams assessed, 5 of which lie on the border between Richmond and the watershed plan for the Town of Richmond. Hopkinton

Road Stream Crossings Dams • 21 crossings are hydraulically undersized • 2 high hazard dams, 3 significant hazard dams, • 31 crossings have high geomorphic vulnerability and 5 low hazard dams • 24 crossings have high flood impact potential • 8 of the 10 dams are considered High or • 22 crossings limit or restrict aquatic passage Intermediate priority for recommended actions Recommendations: Recommendations: • Replace and upgrade priority crossings (see table Alton Pond Dam (Wood River) below) to meet flood resilience and aquatic • Consider dam removal organism passage (AOP) goals • Downstream-most dam on the Wood River, • Consider other upstream and downstream restricting aquatic passage to the river crossings and dams on the same river system • Replacement or reconfiguration of the Church • In general, replace downstream crossings first Street Bridge would be required to accommodate • Perform site-specific data collection, geotechnical dam removal evaluation, hydrologic and hydraulic evaluation, DeCoppett Pond Dam (Beaver River) and structure type evaluation to support design • Consider dam removal • The dam is located on the Beaver River, which is Priority Stream Crossings one of the most valued cold water streams in RI Road Stream Crossing Type and has a known population of Brook Trout New London Double 24” CMP • The impoundment does not appear to support Unnamed Turnpike Circular Conduit any active uses; dam is deteriorating Buttonwood 36” Concrete Unnamed Road Circular Conduit Wood River Junction Dam (Meadow Brook) New London 42” CMP Circular Unnamed • Consider dam removal Turnpike Conduit • Dam in generally poor condition and not Double 36” CMP maintained Hillsdale Road Beaver River Circular Conduit + Overflow Conduit Tug Hollow Pond Dam (Beaver River) Shannock Hill 12’W x 4’H Concrete Beaver River • Consider dam removal to restore connectivity and Road Bridge water quality to this high-value stream Schoolhouse 8’W x 4’H Concrete Beaver River Road Box Culvert New London 46” CMP Circular Beaver River Turnpike Conduit 13’W x 4’H Concrete Unnamed Beaver River Bridge Meadow 7’W x 3’HConcrete Pine Hill Road Brook Box Culvert Old Mountain Double 36” Concrete Beaver River Road Circular Conduit 6.6’W x 7.7’H Meadow Church Street Concrete Box DeCoppett Pond Brook Culvert Dam

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Richmond Elementary School o Install bioretention basins in school lawn Downstream of undersized culvert at Route 138 o Cost: $188,000 (Meadow Brook) • Replace undersized culvert at Rte. 138 (Kingstown Richmond Police Department • Road) with larger bottomless arch culvert that Underground infiltration under parking lots o spans full channel width Cost: $41,000 o • Add roughness elements in channel to encourage • Rhode Island State Police Barracks aggradation and reduce incision o Install bioretention basin next to barracks o Cost: $39,000 Village of Carolina along Route 112 (Upper • Wyoming Dam Fishing Access Pawcatuck River o Bioretention and Pervious Pavers to promote • Breach granite bank/berm that confines the infiltration and prevent erosion channel and cuts off side channel access to allow o Modify boat ramp with articulated concrete access to floodplain block matting to prevent erosion and • Use granite from berm to construct instream sediment transport to river structures o Cost: $161,000

Typical rain garden detail. Bermed, straightened reach of Pawcatuck River along Route 112

Land Use Policy and Regulations • Consider adopting a No Adverse Impact (NAI) Floodplain Management policy Municipal land use policies and regulations can help • Amend zoning ordinance to strengthen flood communities become more resilient to flooding by: management standards • Preserving undeveloped land • Consider implementing fluvial erosion hazard zoning Siting development in locations less vulnerable to • to address riverine erosion hazards flooding, and • Consider amendments to the existing Promoting designs that reduce runoff and are less • conservation/cluster development provisions in the likely to be damaged in a flood zoning ordinance and subdivision regulations to strengthen flood management provisions Recommendations: • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new include: and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Sterling damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 22% of town within watershed the watershed municipalities and partner agencies, has developed • Includes portions of the Wood a watershed-based management plan to enhance the resiliency River and its watershed • 6 stream crossings assessed of the watershed communities to future flooding and protect river • 1 dam assessed and stream ecosystems, including water quality and habitat. The following is a summary of key findings and recommendations of the watershed plan for the Town of Sterling.

Road Stream Crossings Dams • All 6 crossings are hydraulically undersized • 1 significant hazard dam assessed • All 6 crossings have high geomorphic vulnerability • Only a portion of Sterling was assessed; other • 3 crossings limit or restrict aquatic passage dams outside the Wood-Pawcatuck watershed may impact flooding in other parts of the town Recommendations: Recommendations: • Replace and upgrade priority crossings (see table below) to meet flood resilience and aquatic Porter Pond Dam (Wood River) organism passage (AOP) goals • Consider dam removal • Consider other upstream and downstream • Dam is not being maintained and is in disrepair crossings and dams on the same river system • Owner of dam could not be identified • In general, replace downstream crossings first • Impoundment supports limited recreational uses • Perform site-specific data collection, geotechnical evaluation, hydrologic and hydraulic evaluation, and structure type evaluation to support design

Priority Stream Crossings (Sorted in Order of Priority) Road Stream Crossing Type 5’W x 4’H Stone Cedar Swamp Wood River Masonry Box Road Culvert

3’W x 1.5’H Stone Newport Road Carson Brook Masonry Box Porter Pond Dam Culvert

Gallup 20” Concrete Homestead Unnamed Circular Conduit Road

Gallup 12” Concrete Homestead Unnamed Circular Conduit Road

9’W x 3’H Timber Pachaug Trail Wood River Bridge

8’W x 6’H Stone Brown Road Wood River Masonry Bridge

Stream Crossing over Carson Brook at Newport Road

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed field geomorphic assessment was infrastructure (GI) retrofit sites was performed performed for approximately 40 miles of rivers and within the Wood-Pawcatuck watershed. When streams in the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. While field geomorphic assessments No site-specific GI retrofit concepts were developed were not conducted within Sterling, these for Sterling due to the town’s small land area and recommendations apply in the town and throughout limited development within the Wood-Pawcatuck the watershed. watershed and the limited scope of the GI Recommendations: assessment. The Town should incorporate GI approaches into municipal stormwater • Protect existing wetlands as well as stream infrastructure planning and capital improvement connections to wetlands and floodplains plans to address drainage, flooding, and water • Remove floodplain constraints, such as levees or quality priorities including MS4 Permit requirements, berms, where possible both within and outside of the Wood-Pawcatuck • Protect and enhance riparian buffers watershed. GI can be implemented on public sites • Install log jams in select locations along the stream including municipal parking lots and within the corridor to protect banks, create habitat, and re- public right-of-way. form meanders (where human conflicts with meander formation are not present) • Avoid or limit alterations that will straighten or channelize stream channels • Consider removing bank armoring where possible once a protected river corridor is established

View of a typical bioretention cell with mature plantings.

Rendering of a typical bioretention area. Conceptual view of a typical floodplain cross section.

Land Use Policy and Regulations • Amend zoning and subdivision regulations to require that all new development and redevelopment projects Municipal land use policies and regulations can help comply with LID standards consistent with the communities become more resilient to flooding by: Connecticut Stormwater Quality Manual • Preserving undeveloped land • Consider amendments to the zoning and subdivision Siting development in locations less vulnerable to • regulations to promote reduction of impervious flooding, and surfaces and remove barriers to use of LID • Promoting designs that reduce runoff and are less • Consider adopting a No Adverse Impact (NAI) likely to be damaged in a flood Floodplain Management policy • Amend Floodplain Management Ordinance to Recommendations: strengthen flood management standards A review was conducted of the land use policies, • Consider implementing fluvial erosion hazard zoning plans, and regulations of the watershed to address riverine erosion hazards municipalities. Key recommendations of this review • Update design storm precipitation amounts include: • Implement road stream crossing standards for new and replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Voluntown damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 21% of town within watershed • Includes portions of the Ashaway the watershed municipalities and partner agencies, has developed and Wood River watersheds a watershed-based management plan to enhance the resiliency • 7 stream crossings assessed of the watershed communities to future flooding and protect river • 1 dam assessed and stream ecosystems, including water quality and habitat. The following is a summary of key findings and recommendations of the watershed plan for the Town of Voluntown.

Road Stream Crossings Dams • 4 crossings are hydraulically undersized • 1 significant hazard dam • 4 crossings have high geomorphic vulnerability • 1 crossing has high flood impact potential Recommendations: • 2 crossings limit or restrict aquatic passage Green Falls Reservoir Dam (Green Fall River) Recommendations: • Recommended action is to maintain dam in its current state; this dam is considered a low priority • Replace and upgrade priority crossings (see table • Impoundment is located in the Pachaug State below) to meet flood resilience and aquatic Forest and has significant public recreational value organism passage (AOP) goals • Dam is in fair condition • Consider other upstream and downstream crossings and dams on the same river system • In general, replace downstream crossings first • Perform site-specific data collection, geotechnical evaluation, hydrologic and hydraulic evaluation, and structure type evaluation to support design

Priority Stream Crossings (Sorted in Order of Priority)

Road Stream Crossing Type

Bailey Pond Double 30” CMP Carson Brook Road Circular Conduit

12” CMP Circular Sand Hill Road Unnamed Conduit Green Falls Reservoir Dam Tom Wheeler 24” Concrete Unnamed Road Circular Conduit

Green Fall 36” Stone Masonry Sand Hill Road River Box Culvert

36” Concrete Green Fall Road Unnamed Circular Conduit

6’W x 7’H Stone Peg Mill Sand Hill Road Masonry Box Brook Culvert 10’W x 4.4’W Stone Green Fall Road Unnamed Masonry Box Culvert Stream Crossing over an unnamed stream at Tom Wheeler Road

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed field geomorphic assessment was infrastructure (GI) retrofit sites was performed performed for approximately 40 miles of rivers and within the Wood-Pawcatuck watershed. When streams in the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. While field geomorphic assessments No site-specific GI retrofit concepts were developed were not conducted within Voluntown, these for Voluntown due to the limited development and recommendations apply in the town and throughout protected nature of the land within the Wood- the watershed. Pawcatuck watershed and the limited scope of the GI Recommendations: assessment. The Town should incorporate GI approaches into municipal stormwater • Protect existing wetlands as well as stream infrastructure planning and capital improvement connections to wetlands and floodplains plans to address drainage, flooding, and water • Remove floodplain constraints, such as levees or quality priorities including MS4 Permit requirements, berms, where possible both within and outside of the Wood-Pawcatuck • Protect and enhance riparian buffers watershed. GI can be implemented on public sites • Install log jams in select locations along the stream including municipal parking lots and within the corridor to protect banks, create habitat, and re- public right-of-way. form meanders (where human conflicts with meander formation are not present) • Avoid or limit alterations that will straighten or channelize stream channels • Consider removing bank armoring where possible once a protected river corridor is established

Rendering of a typical bioretention area. Conceptual view of a typical floodplain cross section.

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts – West damages, as evidenced by the devastating flooding that occurred in Greenwich 2010. The Wood-Pawcatuck Watershed Association, working with the watershed municipalities and partner agencies, has developed • 51% of town within watershed a watershed-based management plan to enhance the resiliency • Includes portions of the Wood, Usquepaug, and Queen Rivers and of the watershed communities to future flooding and protect river their watersheds and stream ecosystems, including water quality and habitat. The • 21 stream crossings assessed following is a summary of key findings and recommendations of • 2 dams assessed the watershed plan for the Town of West Greenwich.

Road Stream Crossings Dams • 10 crossings are hydraulically undersized • 2 low hazard dams • 12 crossings have high geomorphic vulnerability • Both dams are considered low priority dams • 14 crossings limit or restrict aquatic passage Recommendations: Recommendations: Hazard Pond Dam (Falls River) • Replace and upgrade priority crossings (see table • Consider dam removal below) to meet flood resilience and aquatic • There are no known uses of the impoundment organism passage (AOP) goals • Next dam downstream on the Wood River • Consider other upstream and downstream (Barberville Pond Dam) should be considered for crossings and dams on the same river system removal In general, replace downstream crossings first • Kasella Farm Pond Dam (Breakheart Brook) • Perform site-specific data collection, geotechnical • Current use of the impoundment is unknown evaluation, hydrologic and hydraulic evaluation, • Dam recently reconstructed to build a road across and structure type evaluation to support design crest, but needs repair (crest is not compacted) • Removal should be considered and could be Priority Stream Crossings achieved by enlarging the culverts beneath the (Sorted in Order of Priority) roadway to sufficiently drain the impoundment, Road Stream Crossing Type thereby maintaining the roadway Shetucket 2’W x 1’H Stone Unnamed Kasella Pond Dam Turnpike Conduit 4’ W x 2’H Stone Tillinghast Pond Coney Brook Masonry Box Road Culvert Triple 36” CMP Hazard Road Wood River Circular Conduit 10.5’W x 6.5’H Stone Falls River Road Wood River Masonry Bridge Shetucket 24” Concrete Unnamed Turnpike Circular Conduit Henry Brown Fisherville 48” CMP Circular Road Brook Conduit Plain Meeting 36” Concrete Phillips Brook House Road Circular Conduit Shetucket Factory Double 60” Concrete Turnpike Brook Circular Conduit Henry Brown 36” Concrete Unnamed Road Circular Conduit Stream Crossing over an Plain Meeting Breakheart Double 30” CMP unnamed stream at House Road Brook Circular Conduit Shetucket Turnpike

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed field geomorphic assessment was infrastructure (GI) retrofit sites was performed performed for approximately 40 miles of rivers and within the Wood-Pawcatuck watershed. When streams in the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. While field geomorphic assessments No site-specific GI retrofit concepts were developed were not conducted within West Greenwich, these for West Greenwich due to the limited scope of the recommendations apply in the town and throughout GI assessment. The Town should incorporate GI the watershed. approaches into municipal stormwater Recommendations: infrastructure planning and capital improvement plans to address drainage, flooding, and water • Protect existing wetlands as well as stream quality priorities including MS4 Permit requirements, connections to wetlands and floodplains both within and outside of the Wood-Pawcatuck • Remove floodplain constraints, such as levees or watershed. GI can be implemented on public sites berms, where possible including municipal parking lots and within the • Protect and enhance riparian buffers. public right-of-way. • Install log jams in select locations along the stream corridor to protect banks, create habitat, and re- form meanders (where human conflicts with meander formation are not present) RW56 • Avoid or limit alterations that will straighten or channelize stream channels • Consider removing bank armoring where possible once a protected river corridor is established

Rendering of a typical bioretention area. Conceptual view of a typical floodplain cross section.

Land Use Policy and Regulations • Update and integrate the Town hazard mitigation plan and comprehensive plan to address flood-prone areas Municipal land use policies and regulations can help • Consider adopting a No Adverse Impact (NAI) Floodplain communities become more resilient to flooding by: Management policy • Preserving undeveloped land • Amend zoning ordinance to strengthen flood • Siting development in locations less vulnerable to management standards flooding, and • Consider implementing fluvial erosion hazard zoning to • Promoting designs that reduce runoff and are less address riverine erosion hazards likely to be damaged in a flood • Consider amendments to the existing conservation/cluster development provisions in the Recommendations: zoning ordinance and subdivision regulations to strengthen flood management provisions A review was conducted of the land use policies, • Amend street and parking lot design standards to plans, and regulations of the watershed reduce impervious cover and remove barriers to LID municipalities. Key recommendations of this review • Implement road stream crossing standards for new and include: replacement culverts and bridges

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Westerly damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 77% of town within watershed • Includes portions of the lower the watershed municipalities and partner agencies, has developed Pawcatuck River, smaller a watershed-based management plan to enhance the resiliency tributaries, and associated of the watershed communities to future flooding and protect river watersheds and stream ecosystems, including water quality and habitat. The • 40 stream crossings assessed following is a summary of key findings and recommendations of • 2 dams assessed, one of which lies on the Connecticut border the watershed plan for the Town of Westerly.

Road Stream Crossings Dams • 15 crossings are hydraulically undersized • 2 low hazard dams • 21 crossings have high geomorphic vulnerability • Both dams are deteriorating or in disrepair but • 19 crossings have high flood impact potential are considered low priority dams • 18 crossings limit or restrict aquatic passage Recommendations: Recommendations: Stillmanville Dam (Pawcatuck River) • Replace and upgrade priority crossings (see table • The concrete structure does not prevent fish below) to meet flood resilience and aquatic passage or have a significant impact on flow organism passage (AOP) goals regime • Consider other upstream and downstream • Consider removal to provide river restoration crossings and dams on the same river system benefits In general, replace downstream crossings first • Olaf Farm Pond Dam (Cedar Swamp Brook) • Perform site-specific data collection, geotechnical • Repairs are recommended at this dam. Dense evaluation, hydrologic and hydraulic evaluation, vegetation should be removed and erosion that and structure type evaluation to support design has occurred at the informal secondary spillway should be addressed. Priority Stream Crossings • The owner is currently maintaining the dam and Road Stream Crossing Type wishes to maintain the impoundment Double 32” Concrete • The owner is opposed to removal. Forrestal Drive Unnamed Circular Conduit • If the owner would agree to removal in the future, Westerly- McGowan 24” CMP Circular removal should be considered (low priority) Bradford Road Brook Conduit Pawcatuck 74’W x 14.5’H Broad Street River Concrete Bridge 6” CMP Circular Potter Hill Road Unnamed Conduit Triple 24” Concrete White Rock Road Unnamed Circular Conduit 18” Concrete West Arch Street Unnamed Circular Conduit Perry Healy 12” CMP Circular Ross Hill Road Brook Conduit 32” Concrete Hiscox Road Unnamed Circular Conduit Pawcatuck 117”W X 11’H Stillman Avenue River Concrete Bridge Boom Bridge Pawcatuck 23.4’W x 9.6’H Road River Concrete Bridge Pawcatuck 4.3’W X 8.5’H Stone Post Office Lane River Masonry Bridge Pawcatuck Stone Masonry White Rock Road Stillmanville Dam River Bridge

Green Infrastructure River Corridor A screening-level assessment of potential green A detailed geomorphic assessment was performed infrastructure (GI) retrofit sites was performed for approximately 40 miles of rivers and streams in within the Wood-Pawcatuck watershed. When the watershed. Based on the results of the applied throughout the watershed, GI can help geomorphic assessment, river corridor planning mitigate flood risk resulting from outdated and recommendations were developed to identify undersized storm drainage systems and increase restoration projects that will reduce flood hazards flood resiliency, as well as improve water quality. and downstream sediment loading and improve aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • Grace United Methodist Church o Bioretention adjacent to parking lot Downstream of Bradford Dam; Downstream of o Cost: $36,000 Boom Bridge to top of former White Rock Dam impoundment (Pawcatuck River) Bradford School • • Remove berm on left bank to restore floodplain Underground infiltration and green roof o connection and reduce flood impacts demonstration project Cost: $219,000 ($56,000 for underground o Downstream of Potter Hill Dam in Ashaway infiltration) (Pawcatuck River) • State Street School • Install instream structures to narrow channel, sort o Bioretention and rain gardens and store sediment, and provide cover for aquatic o Cost: $83,000 organisms • Westerly High School o Underground infiltration under parking area At former location of White Rock Dam to o Cost: $29,000 Route 78 Bridge (Pawcatuck River) • Tower Street School and Community Center • Install riparian plantings on right bank near gravel o Bioretention along parking area perimeter pit to slow or halt bank erosion o Cost: $18,000

Typical installation of underground infiltration system below an existing parking lot. Berm confining Pawcatuck River downstream of Bradford Dam Land Use Policy and Regulations • Consider developing a coastal resiliency plan to better protect public infrastructure from coastal flooding and Municipal land use policies and regulations can help sea level rise communities become more resilient to flooding by: • Consider adopting a No Adverse Impact (NAI) Floodplain • Preserving undeveloped land Management policy • Siting development in locations less vulnerable to • Amend zoning ordinance to strengthen flood flooding, and management standards • Promoting designs that reduce runoff and are less • Consider implementing fluvial erosion hazard zoning to likely to be damaged in a flood address riverine erosion hazards • Amend street and parking lot design standards to Recommendations: reduce impervious cover and remove barriers to LID • Update design storm precipitation amounts A review was conducted of the land use policies, • Implement road stream crossing standards for new and plans, and regulations of the watershed replacement culverts and bridges municipalities. Key recommendations of this review • Reference the Wood-Pawcatuck Flood Resiliency include: Management Plan in municipal planning documents

The Wood-Pawcatuck watershed is vulnerable to flood-related Quick Facts - Stonington damages, as evidenced by the devastating flooding that occurred in 2010. The Wood-Pawcatuck Watershed Association, working with • 11% of town within watershed • Includes portions of the Pawcatuck the watershed municipalities and partner agencies, has developed and Shunock Rivers and their a watershed-based management plan to enhance the resiliency watersheds of the watershed communities to future flooding and protect river • 12 stream crossings assessed and stream ecosystems, including water quality and habitat. The • 2 dams assessed following is a summary of key findings and recommendations of the watershed plan for the Town of Stonington.

Road Stream Crossings Dams • 4 crossings are hydraulically undersized • 1 significant hazard dam, 1 low hazard dam • 4 crossings have high geomorphic vulnerability • 5 crossings have high flood impact potential Recommendations: • 7 crossings limit or restrict aquatic passage Liepold Pond Dam (Pawcatuck River) Recommendations: • The dam is being maintained. Ongoing maintenance is recommended. • Replace and upgrade priority crossings (see table • The owner has indicated a desire to maintain the below) to meet flood resilience and aquatic impoundment for private uses organism passage (AOP) goals • Consider other upstream and downstream Stillmanville Dam (Pawcatuck River) crossings and dams on the same river system • The concrete structure does not prevent fish • In general, replace downstream crossings first passage or have a significant impact on flow • Perform site-specific data collection, geotechnical regime evaluation, hydrologic and hydraulic evaluation, • Consider removal to provide river restoration and structure type evaluation to support design benefits

Priority Stream Crossings Road Stream Crossing Type Circular Concrete West Arch Street Unnamed Culvert Pawcatuck Broad Street Concrete Bridge River Pawcatuck Stillman Avenue Concrete Bridge River Pawcatuck Stone Masonry White Rock Road River Bridge Stone Masonry Box Elmridge Avenue Unnamed Culvert Circular Concrete Fairview Drive Unnamed Culvert Circular Concrete Canterbury Lane Unnamed Culvert Circular Concrete Liepold Pond Dam Somersett Drive Unnamed Culvert Timber Ridge Circular Concrete Unnamed Drive Culvert Voluntown Road Circular Concrete Unnamed (Rt. 49) Culvert

River Corridor Green Infrastructure A detailed geomorphic assessment was performed A screening-level assessment of potential green for approximately 40 miles of rivers and streams in infrastructure (GI) retrofit sites was performed the watershed. Based on the results of the within the Wood-Pawcatuck watershed. When geomorphic assessment, river corridor planning applied throughout the watershed, GI can help recommendations were developed to identify mitigate flood risk resulting from outdated and restoration projects that will reduce flood hazards undersized storm drainage systems and increase and downstream sediment loading and improve flood resiliency, as well as improve water quality. aquatic habitat. Sites Identified for GI Retrofits: Recommendations: • West Vine Street School • Protect existing wetlands as well as stream o Install rain gardens near the school building connections to wetlands and floodplains and around the bus loop • Remove floodplain constraints, such as levees or o Cost: $22,000 berms, where possible • Protect and enhance riparian buffers • Install log jams in select locations along the stream corridor to protect banks, create habitat, and re- form meanders (where human conflicts with meander formation are not present) • Avoid or limit alterations that will straighten or channelize stream channels • Consider removing bank armoring where possible once a protected river corridor is established

Typical rain garden detail.

View of a typical bioretention cell or Conceptual view of a typical floodplain cross section. rain garden with mature plantings.

Land Use Policy and Regulations • Implement the recommendations of the Town’s Community Coastal Resiliency Plan, when complete Municipal land use policies and regulations can help • Update the regional hazard mitigation plan annex, and communities become more resilient to flooding by: reference the Wood-Pawcatuck Flood Resiliency • Preserving undeveloped land, Management Plan in municipal planning documents • Siting development in locations less vulnerable to • Consider adopting a No Adverse Impact (NAI) Floodplain flooding, and Management policy • Promoting designs that reduce runoff and are less • Consider amendments to zoning regulations to further likely to be damaged in a flood. strengthen flood management standards • Consider implementing fluvial erosion hazard zoning to Recommendations: address riverine erosion hazards • Amend street and parking lot design standards to A review was conducted of the land use policies, reduce impervious cover and remove barriers to LID plans, and regulations of the watershed • Update design storm precipitation amounts municipalities. Key recommendations of this review • Implement road stream crossing standards for new and include: replacement culverts and bridges

Project funding was provided by the National Fish and Wildlife Foundation Hurricane Sandy Coastal Resiliency Competitive Grant Program