A. Section 210.3 – Coastal Wetlands

A. Definitions

1. Coastal wetlands include salt marshes and freshwater or brackish wetlands contiguous to salt marshes or physiographical features. Areas of open water within coastal wetlands are considered a part of the wetland. In addition, coastal wetlands also include freshwater and/or brackish wetlands that are directly associated with non-tidal coastal ponds and freshwater or brackish wetlands that occur on a barrier beach or are separated from tidal waters by a barrier beach.

2. Salt marshes are areas regularly inundated by salt water through either natural or artificial water courses and where one or more of the following species predominate: smooth cordgrass (Spartina alterniflora), salt meadow grass (Spartina patens), spike grass (Distichlis spicata), black rush (Juncus gerardi), saltworts (Salicornia spp.), sea lavender (Limonium carolinianum), saltmarsh bulrush (Scirpus spp.), high tide bush (Iva frutescens).

3. Contiguous freshwater wetlands are those wetlands which border directly on salt marshes or brackish wetlands or physiographical features and which, except for size limitations, meet the definition of bog, marsh, swamp, or pond under the Rhode Island Freshwater Wetlands Act (R.I.G.L. § 2-1-18 et seq.). All contiguous freshwater wetlands are protected under this Program, regardless of their size.

4. Contiguous brackish wetlands are those wetlands which border directly on salt marshes and where one or more of the following species predominate: tall reed (Phragmites communis), tall cordgrass (Spartina pectinata), broadleaf cattail (Typha latifolia), narrowleaf cattail (Typha angustifolia), spike rush (eleocharis rostellata), chairmaker's rush (Scirpus americana), creeping bentgrass (Agrostis palustris) sweet grass (Hierochloe odorata), wild rye (elymus virginicus).

5. High salt marsh is defined as that portion of the salt marsh that typically is flooded by spring, moon, or other flooding tides but otherwise is not flooded on a daily basis. The vegetative composition of high salt marsh typically consists of one or more of the following: salt meadow grass (Spartina patens); spike grass (Distichlis spicata); black rush (Juncus gerardi); tall reed (Phragmites communis); Sea Lavender (Limonium carolinianum); tall cordgrass (Spartina pectinata); saltmarsh bulrushes (Scirpus spp.); and high tide bush (Iva frutescens).

6. Low salt marsh is defined as that portion of the salt marsh that is flooded daily. The vegetative composition of the low salt marsh typically consists predominantly of smooth cordgrass (Spartina alterniflora).

7. Alterations to coastal wetlands are defined in Section 300.12.

8. Sea Level Affecting Marshes Model (SLAMM) is a model that simulates the dominant processes involved in wetland conversion and shoreline modifications during long-term sea level rise. The model projects the likely wetland conditions for selected sea level rise scenarios and the extent of landward wetland migration.

B. Findings

1. Coastal wetlands are important for a variety of reasons. They provide food and shelter for large populations of juvenile fish and are nurseries for several species of fish. The mud flats and creeks associated with many coastal wetlands are rich in shellfish, particularly soft-shelled clams. Coastal wetlands also provide important habitat for shore birds and waterfowl, and many are among the most scenic features of the Rhode Island shore. Coastal wetlands are effective in slowing erosion along protected shores.

2. Much of the original acreage of coastal wetlands in Rhode Island has been destroyed, and the pressures to fill coastal wetlands continue. Downtown Providence, much of Quonset, and many other low-lying coastal communities are built on what was once coastal wetland. We do not know how much coastal wetland has been destroyed by development, but some 10 percent of our coastal wetlands of 40 acres or more is reported to have been filled between 1955 and 1964. Since coastal wetlands are found in sheltered waters, they frequently coincide with attractive sites for marinas and waterfront homes. The pressures to fill or otherwise alter coastal wetlands therefore remain. According to a 1975 survey, there are some 3,700 acres of salt marsh in the state, of which some 10 percent were fringe marshes less than five yards wide. Approximately 90 percent of the state's salt marshes abut Type 1 and 2 waters.

3. Many of Rhode Island's wetlands are small and, when viewed in isolation, may appear to be of insignificant value. However, these wetlands serve important ecological functions. The Council has sponsored research to investigate the feasibility of rating the relative value of individual coastal wetlands and two years of research revealed that it is not possible to rate coastal wetlands if all ecological considerations are given equal weight. The study also showed that there is little if any correlation between the perceived scenic value of a coastal wetland and its ecological characteristics.

4. Land uses and activities abutting coastal wetlands may have a strong impact upon the wetland itself and wildlife that use the wetland. Nearby drainage patterns which affect sedimentation processes and the salinity of waters may easily be altered, with detrimental effects. The construction of new shoreline protection structures and the bulkheading and filling along the inland perimeter of a marsh prevents inland migration of wetland vegetation as sea level rises, and will very likely result in the eventual permanent loss of coastal wetlands in these circumstances.

5. A study by Hancock (2009¹) using the Sea Level Affecting Marsh Model estimated that a combined 43.6%, or approximately 3300 acres, of existing salt marsh in Winnapaug, Quonochontaug and Ninigret Ponds would be lost in a 1 meter sea level rise scenario by 2100. SLAMM has been used world wide to model the response of coastal wetlands to sea level rise and refined since first developed in 1986.A new CRMC led study (2014) using SLAMM to assess all 21 Rhode Island coastal communities found that approximately 50% of the State’s current 4000 acres of saltmarsh would be inundated and lost under a 3-foot sea level rise and about 75% would be lost under 5-feet of sea level rise. Even considering potential marsh migration and transformation of abutting inland wetlands, there will be an overall net loss of saltmarsh as a result of sea level rise inundation throughout the State.

6. To ensure the long-term viability and ecological functions of salt marshes and other coastal wetlands, it is important to provide unobstructed pathways for these coastal wetlands to migrate landward as sea levels rise. Coastal Buffer Zones (Section 150) abutting coastal wetlands provide protected vegetated upland areas where coastal wetlands may migrate landward over time as sea levels rise.

7. In light of continuing pressures to alter coastal wetlands, and in accordance with the Council's policy of "no net loss", avoidance and minimization of impacts and mitigation for unavoidable losses are necessary tools for retaining and restoring Rhode Island's coastal wetlands.

C. Policies

1. The Council's goal is to preserve and, where possible, restore all coastal wetlands.

2. To offset past losses in coastal wetlands and unavoidable alterations to surviving coastal wetlands: (a) disturbed wetlands should be restored as directed by the Council or enhanced when possible; and (b) in areas selected on the basis of competent ecological study, the Council will encourage the building of new wetlands.

3. The Council’s policy is that all alterations to salt marshes and contiguous freshwater or brackish wetlands abutting Type 1 waters are prohibited except for minimal alterations required by the repair of an approved structural shoreline protection facility (see Section 300.7), or when associated with a Council-approved restoration activity. In Type 1 waters, structural shoreline protection may be permitted only when used for Council-approved coastal habitat restoration projects.

4. It is the Council’s policy that alterations to salt marshes and contiguous freshwater or brackish wetlands abutting Type 2 waters are prohibited except for minor disturbances associated with (a) residential docks and wetland walkover structures approved pursuant to the standards set forth in Sections 300.4 and 300.17, respectively; (b) approved repair of structural shoreline protection facilities pursuant to Section 300.14; or, (c) Council-approved restoration activities.

5. Coastal wetlands designated for preservation adjacent to Type 3, 4, 5, and 6 waters are identified on maps available for inspection at the Council's offices and at the town halls of coastal cities and towns. In these designated wetlands only the following alterations may be permitted: minor disturbances associated with (a) residential docks and wetland walkover structures approved pursuant to the standards set forth in Sections 300.4 and 300.17, respectively; (b) approved repair of structural shoreline protection facilities pursuant to Section 300.14; (c) Council-approved restoration activities; or (d) Council-approved limited view restoration projects for existing hospitality industry businesses. Approval of limited view restoration projects requires a public access plan consistent with Section 335 subject to CRMC approval and requires that wetlands and other shoreline natural resource areas be placed in a conservation easement at a ratio of 5:1 (e.g., 5 times the area to be restored for a view must be preserved). The area to be restored for a view shall also be included in the conservation easement along with a long-term management plan for the view restoration area. All view restoration projects must demonstrate through aerial photographic evidence that a view which supported an existing hospitality industry business has been lost over time by the growth of forested wetland vegetation. Limited view restoration projects are prohibited bordering Type 1 and 2 waters and for all existing and proposed residential projects bordering all water types. Dredging and filling in these designated coastal wetlands are prohibited. The maps of designated coastal wetlands serve to identify individual wetlands; in all cases precise boundaries shall be determined through a field inspection when proposals that could impact these features are being considered. In support of this goal, the Council supports a policy of "no net loss" of coastal wetland acreage and functions as a result of coastal development.

6. Salt marshes adjacent to Type 3, 4, 5, and 6 waters that are not designated for preservation may be altered if: (a) the alteration is made to accommodate a designated priority use for that water area; (b) the applicant has examined all reasonable alternatives and the Council has determined that the selected alternative is the most reasonable; and (c) only the minimum alteration necessary to support the priority use is made.

7. Any alteration of coastal wetlands shall be consistent with Section 300.12.

8. It is the Council’s goal to provide for maximum Coastal Buffer Zone widths for projects abutting coastal wetlands that are adjacent to Type 1 and 2 waters and for coastal wetlands designated for preservation adjacent to Type 3, 4, 5, and 6 waters. In those cases where the Council may grant a variance on small lots the minimum Coastal Buffer Zone width should be no less than 25 feet.

9. It is the Council’s goal to provide maximum Coastal Buffer Zone widths for projects abutting coastal wetlands that are likely, based on site conditions and best available information, to migrate landward with sea level rise. These coastal wetlands do not abut seawalls, bulkheads or other structural shoreline protection facilities or elevated landforms such as bluffs, cliffs, or rocky shorelines, among others. These unobstructed coastal wetlands will migrate landward as sea level rises and Coastal Buffer Zones provide protected upland areas that may transition to coastal wetlands in the future.

10. The Council adopts the Sea Level Affecting Marshes Model (SLAMM) maps for all 21 Rhode Island coastal communities for coastal wetland restoration and adaptation planning purposes. The use of the SLAMM maps is intended to inform the public, state and local authorities of the likely condition of coastal wetlands and their landward extent under future sea level rise scenarios and to assist in adaptive ecosystem management and planning. The Council’s SLAMM maps are hereby incorporated by reference and are available on the CRMC web site at: www.crmc.ri.gov.

D. Prohibitions

1. Alterations to salt marshes and contiguous freshwater or brackish wetlands abutting Type 1 waters are prohibited except for minimal alterations required by the repair of an approved structural shoreline protection facility, or when associated with a Council-approved restoration activity. In Type 1 waters, structural shoreline protection may be permitted only when used for Council-approved coastal habitat restoration projects.

2. Alterations to salt marshes and contiguous freshwater or brackish wetlands abutting Type 2 waters are prohibited except as may be permitted in C.4 above.

3. Alterations to coastal wetlands designated for preservation adjacent to Type 3, 4, 5, and 6 are prohibited except for the activities listed in C.5 above. Dredging and filling in these designated coastal wetlands are prohibited.

4. Limited view restoration projects are prohibited bordering Type 1 and 2 waters and for all existing and proposed residential projects bordering all water types

5. Any limited view restoration project which does not strictly adhere to the Council’s policies and standards as stated in Sections C and E herein are prohibited. Should the hospitality use be discontinued the subject property will no longer qualify for this provision and the limited view restoration Assent will become null and void.

E. Standards

1. Limited View Restoration:

¹ Hancock, Robert. 2009. Using GIS and simulation modeling to assess the impact of sea level rise on coastal marshes. http://nrs.uri.edu/docs/nrs600/2009/AbstractsPDF/Hancock_Abstract_2009.pdf

The Rhode Island Coastal Resources Management Council (CRMC) and its partners have developed Sea Level Affecting Marshes Model (SLAMM) Maps for the coastal wetlands of all 21 Rhode Island coastal communities. The purpose of these SLAMM maps is to show how coastal wetlands will likely transition and migrate onto adjacent upland areas under projected sea level rise scenarios of 1, 3 and 5 feet in the coming decades. These maps are intended to support state and local community planning efforts and to help decision makers prepare for and adapt to future coastal wetland conditions despite the inherent uncertainties associated with future rates of sea level rise.

The SLAMM maps were developed using a digital wetlands coverage derived from the 2010 National Wetlands Inventory for Rhode Island. The elevation data used in the model was developed from the 2011 USGS LIDAR elevation dataset. These maps were developed using the “protection off” mode for the model simulations, thereby depicting the highest potential for marsh migration despite current limitations such as parking lots, roads or other development. In this way the maps illustrate opportunities for conservation and potential land modification to enhance wetland migration and restoration. The SLAMM data do not consider natural processes such as coastal erosion or the impacts of coastal storms that can have significant influence on shoreline location and sediment dynamics. Despite these limitations the data still provide a valuable tool to identify those places that provide the best opportunity for future saltmarsh habitat and conservation priorities, and provide valuable information to help plan for new development and infrastructure. Additional map parameters, data sources and caveats can also be found at www.crmc.ri.gov

These SLAMM maps are Geographic Information System (GIS)-based map images exported as PDF files to reduce file size and ease of access. In total there are 149 map panels that cover the entire Rhode Island shoreline and each panel has four maps showing the initial (current) wetland condition followed by 1, 3, and 5-foot of sea level rise scenarios.

No warranty is expressed or implied by the CRMC and its SLAMM project partners related to the spatial accuracy of these maps and promote no other use of these maps and data other than as a planning tool. These maps should not be used for, and are not intended for, survey and engineering purposes. The data do not take the place of a legal survey or other primary source documentation. They were created for general reference, informational, planning, and guidance use. They are not a legally authoritative source as to the exact location of natural or manmade features.

These maps are herein incorporated under Section 210.3 of the RICRMP. They can be examined at the Council’s office in Wakefield, at the Secretary of State’s office, and on-line at the Council’s website: www.crmc.ri.gov.