Explore the Science

 

o

Our Region at a Glance

 

Get your bay and watershed facts — quick.

 

Little Narragansett Bay

Estuary Proper: 4.8 square miles
Salty Shoreline: 37 miles (including islands)
Watershed: 317 square miles
Max Elevation: 673 feet (in West Greenwich)
Residents: 78 thousand people
Towns & Cities: 4 in CT, 9 in RI
Major Tributaries: Wood River and Pawcatuck River
Streams & Rivers: 521 miles
Invisible Spacer

RI Coastal Ponds

Ponds: 8.7 square miles
Salty Shoreline (Ponds): 136 miles (including islands)
Salty Shoreline (South Coast): 32 miles
Watershed: 56 square miles
Max Elevation: 286 feet (in South Kingstown)
Residents: 28 thousand people
Towns & Cities: 3 in RI
Major Tributaries: Saugatucket River
Streams & Rivers: 49 miles

Narragansett Bay

Estuary Proper: 196 square miles
Max Depth: 194 feet (near Newport)
Salty Shoreline: 563 miles (including islands)
Watershed: 1,705 square miles
Max Elevation: 1,388 feet (near Worcester)
Residents: 1.95 million people
Towns & Cities: 71 in MA, 34 in RI
Major Tributaries: Blackstone River, Taunton River, and Pawtuxet River
Streams & Rivers: 3,578 miles

 
 

o

Narragansett Bay

 
 
NBW3.png
 

What has the latest bay science shown us?

In the Bay, salt marshes and sea grasses have declined considerably from historical extents. Fish communities are changing toward seasonal and mid-Atlantic species. Climate change has brought higher rainfall, temperatures, and sea levels. Still, nutrient reductions have resulted in recovery in the Bay, including visible recovery on the sea floor. Meanwhile, the bay continues to support many vibrant uses including shellfishing, swimming, and boating.

 

55% of nitrogen was reduced to the bay since 2000

Since 2000, sewage treatment facilities have dramatically reduced nutrient loadings—including -42% in total phosphorus—due to management policies and major upgrades. Excessive nutrients harm aquatic life by stimulating algae growth, which leads to depleted oxygen as algae die and decompose.

Half of the Bay is still unhealthy for aquatic wildlife

Just half of the estuarine waters assessed by states were determined to be in healthy condition for fish and other aquatic life as of 2014. The remainder was impacted by nutrient enrichment and depleted oxygen, including the Upper Estuary and Mount Hope Bay. However, about one quarter of the Bay remains unassessed.

Life on the seafloor has been recovering

Since 1988, benthic habitat has improved over 30 years of nutrient reductions. From 2008-2018, habitat at 80% of sampling sites improved or maintained good quality. Intermediate and mature communities were found at 71% of sites in 2018. Room for improvement remains in areas of the Upper Bay.

Rainfall has increased by 0.4 inches per decade

Average annual rainfall has increased 0.4 to 0.7 inches per decade since 1895, with volumes during intense storms increasing 71% since 1965. Local projections include increased volume, frequency, and intensity of rainfall events, and changing seasonality with increased winter volume and summer drought-like conditions.
 

Sea level rose 9 inches since 1930

Sea level rose by nine inches from 1930 to 2017 at the Newport tide gauge. Models of different greenhouse gas emissions scenarios indicate another nine to eleven feet by 2100. Already, some roads and other infrastructure in low-lying, coastal areas are inundated during extreme high tides.

3,371 acres of salt marsh were observed in 2012

Salt marshes provide nursery grounds, storm and flooding protections, and filter polluted runoff. From the 1800s to the 1970s, over 50% of salt marshes in the bay were lost. Of the 3,371 acres mapped in 2012, an estimated 13-87% may become submerged under 1- and 5-foot sea level rise projections, respectively.

Bay temperatures rose 3°F since 1960

Bay water and air temperatures have increased by 3°F since 1960 and air temperature is projected to increase another 5 to 10°F by 2100. Studies show that warming will become faster, causing ecosystem impacts and potentially affecting public health concerns such as bacterial contamination of shellfish beds.

Fish communities are changing

Seasonal migrant species such as scup, black sea bass, and butterfish have displaced demersal resident species such as winter flounder and red hake. As the bay and open ocean continue to warm, fish communities will trend from a southern New England temperate toward a Mid-Atlantic estuarine community.

 

Just 479 acres of seagrasses were observed in 2016

Prior to the 1930s, seagrasses were prevalent throughout the bay, including the Providence River Estuary and Mount Hope Bay. After a marked decline, seagrasses are now found predominantly in the Lower Bay. Warmer temperatures and sea level rise may impair seagrass growth and survival.

85% of the Bay is fit for recreation

Most of the estuarine waters assessed by states were found suitable for swimming, boating, and other such recreational uses as of 2014. Some exceptions include estuarine waters in the Providence River, Palmer River, Newport Harbor, lower Mount Hope Bay, and some embayments in Greenwich Bay. Only about 5% of the Bay remains unassessed.

63% of shellfishing areas were open in 2015

In the last two decades, dangerous bacterial inputs in the upper estuary have been reduced by wastewater treatment upgrades and management of combined sewer overflows in Providence and Fall River. Since in 2005, open shellfishing acreage began to increase, including 3,711 new acres in upper estuary in 2017.

There are 338 public access points to the shore

From the South Shore up to Providence, the public can access the shore through boat ramps, beaches, rights-of-way, town docks, overlooks, nature trails, and preserves. Only ~20%--70 public access points--have never been restricted or impaired for recreational uses such as swimming and shellfishing due to bacterial pollution. Those sites fall in the southern half of the bay, where tidal flushing is higher.
 

What does the science tell us about our watershed?

In the Narragansett Bay watershed, our population and the landscape has changed dramatically since the Industrial Revolution. As population and developed areas grow, forests continue to shrink. Loss of the natural protections by forests and wetlands impacts wildlife and the health of our inland and coastal waters. These impacts are felt particularly in our underserved communities, a legacy that has been shaped by the history of our landscape.

 

Our population grew by 8% since 1990

The number of people living in the watershed continues to grow. Notably, recent population growth and land development have been concentrated in previously rural, forested areas. The amount of developed land per capita is higher and increasing in rural and suburban areas, indicating sprawl.

We lost 6% of our forests and gained 10% developed lands since 2001

Our watershed is 42% forested and 34% developed (2016)—with coastal areas the most developed (up to 86%). From 2001-2016, forests declined by 6% and developed lands increased by 10%. Change around Taunton River has been particularly dramatic—with up to 21% developed land expansion in some areas since 2001.

The watershed is 14% impervious cover

“Impervious cover” refers to buildings, pavement, and other surfaces that do not absorb water when it rains. Impervious cover greater than 10% has known impacts to watershed health. The immediate coastal lands that drain to the Bay are 20% impervious. 36 of our 52 subwatersheds exceed 10% impervious.

43% of natural lands remain unprotected

We have protected over 17% (180,000 acres) of forest, wetland, saltmarsh, brushland, agricultural land, and some developed land area of the watershed. Still unprotected are 43% (nearly 455,000 acres) of undeveloped lands—that includes over 17% of the watershed lands that are high ecological integrity.
 

>50% of assessed streams/rivers are fit for aquatic wildlife

Nearly one quarter of freshwater streams and rivers assessed by states were found impacted by excess nutrients and oxygen depletion, including the entire Blackstone River. Another 25% was found unhealthy for fish and wildlife for other reasons. Nearly 40% remain unassessed for healthy aquatic wildlife conditions by the states.

25% of assessed ponds/lakes are fit for aquatic wildlife

75% of ponds and lakes assessed by states were found unhealthy for fish and aquatic wildlife. 25% were found impacted by excess nutrients and oxygen depletion, and 50% for other reasons. However, nearly 72% remain unassessed for healthy aquatic wildlife conditions by the states.

34% of assessed streams/rivers are fit for recreation

Over 60% of freshwater streams and rivers assessed by states across the watershed were found not suitable for swimming, boating, and other such recreational uses due to bacterial pollution. That includes up to 80% in the Taunton River watershed and coastal areas around the bay. Over 40% remain unassessed by the states for recreational use.

80% of assessed ponds/lakes are fit for recreation

Just 2% of freshwater ponds and lakes assessed by states across the watershed were found not suitable for swimming, boating, and other such recreational uses due to bacterial pollution. However, around 50% remain unassessed by the states for recreational use.
 

37 sewage treatment plants serve 62% of residents

The 37 wastewater treatment facilities in the Narragansett Bay watershed discharge approximately 203 million gallons per day of treated wastewater, based on monthly averages from 2013 to 2015. These plants serve approximately 62% of the population.

Higher-risk populations see greater burdens

Race, ethnicity, income, language, and education are core factors used by federal and state agencies to understand susceptibility to environmental burdens. 65% of towns in the region have populations above the 80th %ile of higher susceptibility. The legacy of environmental burdens on our underserved communities has been shaped by the history of our landscape.
 

 
 

o

Little Narragansett Bay

 
 
LNB.png
 

What has the latest science shown us?

Compared to the Narragansett Bay watershed, the Little Narragansett Bay watershed is more heavily forested and protected under conservation lands. Water quality impacts tend to be concentrated near developed areas. Within the bay proper, seagrasses remain scarce and shellfishing is typically restricted. The Barn Island Wildlife Management Area—the largest managed coastal habitat area in Connecticut—protects substantial areas of healthy salt marsh, deciduous forest, and avian habitat.

 

605 acres of salt marsh were observed in 2012

Salt marshes provide nursery grounds, storm and flooding protections, and filter polluted runoff. As of 2012, 605 acres of brackish and salt marsh were mapped in Little Narragansett Bay via aerial surveys, with much of it protected within the Barn Island Wildlife Management Area in Connecticut.

96 acres of seagrasses were observed in 2016

In Little Narragansett Bay, the largest seagrass area is bookended by the Sandy Point Nature Preserve and the Napatree Point Conservation Area. Seagrasses declined from 201 acres in 2012 to 96 in 2016. This may be tied to a broader pattern of decline across the region, or may simply reflect variable seasonal conditions.

100% of the bay is closed to shellfishing

Bacterial pollution from point and nonpoint sources to the Little Narragansett Bay continue to restrict ALL recreational shellfish harvesting within the bay proper as of 2019. However, nearby areas outside the bay are approved or conditionally approved for shellfishing.

There are 11 public access points to the shore

From the bay up the Pawcatuck River, the public can access the shore through a variety of boat ramps, beaches, and nature spaces. However, all 11 public access points have been variously restricted or impaired for select recreational uses—such as shellfish harvest—due to bacterial pollution.
 

>70% RI-assessed streams/rivers are fit for aquatic wildlife

Based on data from Rhode Island (RI) only, the majority of freshwater streams and rivers assessed by RI were found healthy for fish and aquatic wildlife. 28% exhibited impacted conditions and 11% of all streams and rivers remain unassessed for aquatic wildlife conditions in RI. Analysis pending for Connecticut.

73% RI-assessed ponds/lakes are fit for aquatic wildlife

Based on data from Rhode Island (RI) only, nearly three quarters of ponds and lakes assessed by RI were found healthy for fish and aquatic wildlife. Roughly 10% were found impacted by excess nutrients and oxygen depletion. Roughly 15% remain unassessed for aquatic wildlife conditions in RI. Analysis pending for Connecticut.

60% RI-assessed streams/rivers are fit for recreation

Based on data from Rhode Island (RI) only, 60% of freshwater streams and rivers assessed in the watershed by RI were found suitable for swimming, boating, and other such recreational uses. Roughly 40% were found impacted by bacterial pollution. Roughly 10% remain unassessed by RI for recreational use. Analysis pending for Connecticut.

100% RI-assessed ponds/lakes are fit for recreation

Based on data from Rhode Island (RI) only, ALL ponds and lakes assessed by RI were found suitable for recreational uses like swimming and boating. Just 4% remain unassessed for recreational use in the RI portion of the watershed. Analysis pending for Connecticut.
 

The population grew by 21.5% since 1990

The number of residents in the Little Narragansett Bay watershed continues to grow. With an over 20% increase since 1990, the largest growth occured between 1990-2000. We saw a 14% increase in the population during those years.

We lost 1.4% of forests and gained 3.5% developed lands since 2001

Little Narragansett Bay's watershed is 61% forested and just 11% developed (2016). The bulk of development in the watershed is in the Westerly-Stonington area. From 2001-2016, forests declined by 1.4% while developed lands increased by 3.5%.

The watershed is less than 5% impervious cover

“Impervious cover” refers to buildings, pavement, and other surfaces that do not absorb water when it rains. Impervious cover greater than 10% has known impacts to watershed health. Based on data in Rhode Island (RI) only, most of RI subwatersheds fall below 7% impervious cover--except for the Lower Pawcatuck River watershed which is 31% impervious.

Upper Wood River has the most protection in the watershed

Based on data in Rhode Island (RI) only, RI has protected 33% (nearly 60,000 acres) of watershed lands. The highest protections surround the Upper Wood River (over 18,000 acres). Still unprotected are nearly 50% of undeveloped lands in RI areas of the watershed, including >27% of high ecological integrity.

 
 

o

Coastal Ponds

 
 
SWCP.png
 

What has the latest science shown us?

The Rhode Island coastal salt ponds are a treasured coastal resource for Rhode Islanders and visitors alike. Each pond has a unique identity, and supports a range of wildlife and coastal habitats and well as many important commercial and recreational activities. The watershed is small with a growing population and expanding development in the last twenty years. Notable conservation efforts have contributed to keeping the many public access points, vibrant salt marshes, and shellfishing areas fit for use.

 

944 acres of salt marsh were observed in 2012

Salt marshes provide nursery grounds, storm and flooding protections, and filter polluted runoff. As of 2012, 944 acres or brackish and salt marsh were mapped in the coastal ponds via aerial surveys.

442 acres of seagrasses were observed in 2016

Warmer temperatures and sea level rise may impair seagrass growth and survival. In the Ponds, seagrasses declined from 603 acres in 2009, to 523 acres in 2012, and to 442 acres in 2016. This may be tied to a broader pattern of decline across the region, or may simply reflect variable conditions in the two sampling years.

78% of shellfishing area were open in 2015

Bacterial pollution from point and nonpoint sources continue to restrict 22% of recreational shellfish harvesting areas within the ponds. Still, the majority (78%) of the ponds were approved for shellfishing in 2015.

There are 63 public access points to the shore

From the South Shore beaches to the Coastal Ponds, the public have ample access the shoreline through Rhode Island’s renowned beaches, boat ramps, rights-of-way, and nature spaces. Only 15 of these public access points have been variously restricted or impaired for select recreational uses—such as shellfish harvest—due to bacterial pollution. These access points are all to the Coastal Ponds.
 

60% of assessed streams/rivers are fit for aquatic wildlife

Nearly 60% of freshwater streams and rivers assessed by states were found healthy for fish and aquatic wildlife. None exhibited impacted conditions; however, roughly 50% of all streams and rivers the Coastal Ponds watershed remain unassessed for aquatic wildlife conditions.

85% of assessed ponds/lakes are fit for aquatic wildlife

Just 15% of ponds and lakes assessed by states were found unhealthy for fish and aquatic wildlife. due to excess nutrients and oxygen depletion. 85% were classified as acceptable conditions. Roughly 20% remain unassessed for aquatic wildlife conditions.

No assessed streams/rivers are fit for recreation

All ~23 miles of freshwater streams and rivers assessed in the Coastal Ponds watershed by states were found unsuitable for swimming, boating, and other such recreational uses due to bacterial pollution. Roughly 45% of all streams and rivers remain unassessed for recreational use in the watershed.

100% of assessed ponds/lakes are fit for recreation

ALL ponds and lakes assessed by states were found suitable for recreational uses, such as swimming and boating. However, 20% remain unassessed for recreational use in the watershed.
 

The population grew by 23% since 1990

The number of residents in the Coastal Ponds watershed continues to grow. With a 23% increase since 1990, the largest growth occured between 1990-2000. We saw a 21% increase in the population during those years.

We lost 5.1% forests and gained 6.3% developed lands since 2001

The Coastal Ponds watershed is 40% forested and 30% developed (2016). The bulk of development in the watershed is clustered in coastal areas. From 2001-2016, forests declined by 5% while developed lands increased by 6%.

The watershed is 11% impervious cover

“Impervious cover” refers to buildings, pavement, and other surfaces that do not absorb water when it rains. Impervious cover greater than 10% has known impacts to watershed health. The Coastal Ponds watershed is 11% impervious cover--above the threshold considered acceptable.

Nearly 40% of undeveloped lands remain unprotected

25% (roughly 8,600 acres) of watershed lands are protected. Nearly 40% (roughly 13,000 acres) of undeveloped lands remain unprotected, including >17% of that are high ecological integrity lands in the watershed.