Newport Comprehensive Land Use Plan - Existing Conditions | Page 148

Newport Comprehensive Land Use Plan

Coastal Marshland

Although not as extensive as in other coastal communities, Newport’s coastal wetlands play an important ecological
and aesthetic role. These resources are especially vulnerable to sea level rise. The Sea Level Affecting Marshes
Model (SLAMM) is a simulation of the process in which wetlands are converted and shorelines are modified during
consistent sea level rise. As expected, the impacts on wetlands and shorelines vary based on how extensive the sea
level rise is. SLAMM maps have been created for Newport’s wetlands and shorelines and can be seen on Maps 10-3,
10-4, and 10-5. Each of these depicts wetland and shoreline impacts based on rises in sea level of 1 foot, 3 feet, and
5 feet, respectively.
Sea level rise is having a significant impact on these resources, both in terms of inundation, but also by changing the
type and character of the ecological communities which depend upon these areas. Evidence has been developed to
show that in certain cases, these areas are migrating as saline water infiltrates the underlying soils. As this saltwater
“lens” pushes farther inland, it can also impact private potable and irrigation wells, particularly during dry periods
when excessive pumping can induce infiltration. Planning for these changes must include the potential to set aside
sufficient viable areas to accommodate migrating salt marsh areas.

Floodplains

A floodplain is an area of land that is prone to temporary inundation during times of high water, typically associated
with seasonal changes in rainfall and/or snow melt. Long considered waste areas to be filled, people are now
beginning to understand and appreciate their value and the need to protect these important natural resources. In
essence, floodplains are part of nature’s safety buffer, allowing ecosystems to manage the damage and stress caused
by severe storms and floods. Also, as a result of their unique characteristics, they have developed equally unique
communities of plants and fauna which typically do not thrive in other environments.
However, due to its geology, topography and glacial history, Newport does not contain extensive floodplain farmland.
In fact, for the most part, Newport’s floodplains are fairly localized. The Federal Emergency Management Agency
(FEMA) has established 100 and 500 year flood plains for virtually the entire country, including for Newport. These
maps are used as Flood Insurance Rate Maps (FIRMs) to indicate areas where property owners located in
communities which participate in the National Flood Insurance Program (NFIP) must meet certain construction and
design standards. More rigorous standards apply in coastal “V” zones, which are areas that are subject to high winds
and wave action during storms.
A 100-Year flood is a flood that has a 1% chance of occurring in the any 100 year period and a 500-Year flood is a flood
that has a .2% chance of occurring in any 500 year period. The 100-Year and 500-Year Flood Zones for Newport can be
seen on Map 14-1.
With some notable exceptions, most of Newport’s flood plains have been developed (or filled in) for many decades,
even centuries. The principal developed areas that are most at risk for flooding include the northern half of Goat
Island, the Harbor/Lower Thames area, portions of the Navy base, the area around 3rd Street / Training Station Road,
and the Price, Goose and Cherry Necks. “Undeveloped” flood plain areas include the large floodplain extending north
from Ocean Drive more or less through the Newport Country Club to Brenton Cove at Harrison Avenue; and Lily,
Almy, Easton and Green End Ponds. It is important to note that these ponds are also subject to saltwater wave
action. This is a serious threat with respect to Easton Pond in particular. More information about flooding can be
found in Chapter 14, Natural Hazards and Climate Change.

Page 10-6

Draft Existing Conditions (March 2016)