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Governments Plan for Development of Land Vulnerable to Rising Sea Level: Southeastern Connecticut


The Southeastern Connecticut Planning Region comprises roughly 560 square miles and 18 towns, stretching along the Long Island Sound coastline from the Rhode Island border to East Lyme. The region contains both the Thames and Niantic rivers and numerous bays, inlets, and populated islands. In contrast with the western parts of the state, southeastern Connecticut remains largely undeveloped. In 2000, forests, wetlands, and water bodies constituted 55.5 percent of the regional land area, and urban areas only 11.3 percent. Agricultural and recreational lands and committed open space accounted for another 19.5 percent of the land area. Since 1990, when 61 percent of the regional land area was undeveloped, about 1 percent of the region has been developed every two years.

Southeastern Connecticut has seen substantial growth in low-density residential development since 1990. Rural communities that cover large areas of open land in proximity to I-95, such as Lisbon, are experiencing major residential and commercial growth while urban centers like Norwich and New London are not growing at all. Until recently, the region received large amounts of defense funding for submarine manufacturing at Electric Boat, located in Groton. With the end of the Cold War, the demand for submarines has decreased, and gaming, tourism, and pharmaceuticals have become the principal employers in the region. The very large Foxwoods Casino is located roughly 6 miles from the Thames River, and the slightly smaller Mohegan Sun gaming facility is closer to the river. The 115 square miles of Southeastern Connecticut that are intensely developed are primarily concentrated along the Long Island Sound coastline and the Thames River. Several of these areas, including Mason's Island in Stonington, Waterford, and Groton, have very high property values. The population with homes immediately along the coast is far wealthier than the population of the region living farther inland from the shore.

The absence of public water and sewer systems is a major factor in the dispersed development patterns seen in the region. East of the Thames River, only Pawcatuck (Stonington), Groton, and Mystic have sewage treatment facilities. Several municipalities west of the Thames, including New London, Montville, and Griswold, are also served by sewer, but on-site subsurface septic systems remain the primary disposal system in the region. On Black Point in East Lyme and Mason's Island in Stonington, where traditionally seasonal residences are now being occupied year-round, septic systems are becoming overwhelmed more often than before.

As in the Connecticut River Estuary Region, septic systems that serve most of the low-density, seasonal residences on the coast discourage further development. Thus, the presence of sewers and water systems can serve as a predictor of growth patterns in rural and suburban areas along the coast; where sewers are built, development follows.

Although sewer construction is a local decision, it is sometimes opposed by residents who want to maintain the rural character of their communities. The lack of sewer systems was cited as a reason for the East Lyme Zoning Commission's denial of the application to build 894 housing units on the 220-acre Oswegatchie Hills area bordering the Niantic River and the Inner Niantic Bay. Some community interests, however, favor economic growth because of the associated increase in the property tax base. Once a municipality has constructed a sewage treatment facility and other development infrastructure, they will define outlying areas to which services are likely to be expanded in the future. These decisions can reveal the policy of a municipality toward growth. According to regional planners at SCCOG, the town of Montville may have plans to expand sewer lines as a means to spur development along the Route 32 corridor.

Likelihood of Shore Protection

Shore protection is almost certain for most of the Southeastern Planning Region. Nevertheless, our map shows a number of undeveloped areas that may be open for wetland migration. Sections of the shoreline in Waterford are sparsely developed and are currently unarmored; lands on the ocean side of Old Black Point Road in East Lyme are marshy and undeveloped; Griswold Island in East Lyme does not contain any structures; and the Connecticut College Arboretum and Natural Area is a privately protected conservation area (see #8 on Figure 7).

The general approach of the study originally identified some other areas of undeveloped or intermediate lands where we might normally expect shore protection to be less likely, but the staff of the Southeastern Connecticut Council of Governments suggested that that shore protection was likely or almost certain. The Council of Governments suggested the following changes compared with our general approach:
1. Change areas interior of the major roadways in East Lyme and Waterford to shore protection almost certain (brown). Development pressure, which is already significant, is likely to proceed in these areas over the long term. The two casinos, which employ about 10,000 people each, have been a large reason for the continued residential development patterns in the region. Additional areas inland of Interstate 95 and Route 1 in Groton and Lyme were also changed to brown (see #1 on Figure 7).
2. Change Naval Submarine Base lands from brown to red. This follows the general procedure in other states in which we have conducted this study to show military installations as shore protection likely. The base, located on about 285 acres in Groton, was once slated to be closed but was later removed from this list. If the base were to be closed at some point in the future, the region would most likely seek to convert it to some water-based use. Although some retired bases in the Northeast have quickly been redeveloped for other uses, others have taken 20 or more years to be utilized. Environmental problems at the Groton site would most likely require significant remediation efforts. Given the long-term uncertainty of the site's use, the region suggested we continue to show these lands as protection likely but not certain (red).
3. Change areas in Pawcatuck from blue to protection likely (red). Given the uncertainty of future development in this area and the high property value of coastal lands, planning staff suggested we depict it as protection likely.

On the other hand, the SCCOG explicitly agreed with many of close cases as depicted in the maps.
1. The New London/Groton Airport is shore protection almost certain (brown).
2. The Oswegatchie Hills area in East Lyme has not been developed. It is appearing more likely that this land will be put into preserve. Therefore, staff suggested we continue to depict this area as protection unlikely (blue).
3. As the only residential area built on sand in the Southeastern Region, lands in Groton Long Point are most vulnerable to sea level rise. Given the existing development in this area and the high property value, staff suggested we leave this area as shore protection almost certain (brown).
4. Land on the east bank of the Thames River in Preston might be purchased by the state to turn into low cost housing and is currently depicted on the map as shore protection likely. Given this uncertainty, staff suggested we continue to show this area as red.
5. The small off-shore islands near Stonington are state-owned and uninhabited. These are are unlikely to be protected (blue).
6. Since most tidal wetlands are hemmed in by existing development, it is unlikely that any tidal wetlands in the Stonington area would remain if there were a rise in sea level of the magnitude of 3.5 feet or more (e.g., on Barnes Island).

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Governments Plan for Development of Most Land Vulnerable to Rising Sea (PDF, 7 pp., 1.3 MB) was originally published in Environmental Research Letters , Issue 3, Volume 4 (2009).

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