The coastal wetland GIS data layer, referred to in this document as the "matrix", was developed through aerial photography interpretation by the Natural Resources Assessment Group, University of Massachusetts working with the Narragansett Bay Estuary Program and the U.S. Fish and Wildlife Service. This photo–interpretation effort resulted in delineation of wetland "sites" and "complexes" (groups of sites). A report by Irene Huber documenting this effort (Photointerpretation of Buffer Zones, Coastal Wetland Potential Restoration Sites, and Hardened Shorelines in the Narragansett Bay Estuary) is available on CD–ROM (Rhode Island Habitat Restoration Site Selection Tools: Seagrass and Salt Marsh Habitats), which can be ordered on-line from www.edc.uri.edu/restoration/html/spatial/modlsalt.htm. These data were used in a habitat restoration site selection tool, and full metadata describing their development is available on that CD–ROM.
These wetland data were augmented with attribute information on habitat impairment and spatial analyses by the University of Rhode Island (URI) Environmental Data Center working with the Narragansett Bay Estuary Program and Save The Bay. The assignment of each site to a complex was completed through the expert opinion of Helen Cottrell, R.I. Dept of Environmental Management Narragansett Bay Estuary Program, and Andy Lipsky of the U.S. Department of Agriculture, Natural Resources Conservation Service (formerly of Save the Bay).
Metadata for the Matrix
The matrix attributes were developed through spatial analysis of the photo–interpreted wetlands and two datasets that document Narragansett Bay’s externally impacted and internally impacted wetlands. External impacts refer to off–site sources of degradation, such as golf courses; internal impacts refer to on–site impairments, such as tidal restrictions. These analyses resulted in an enhanced wetland dataset containing all impacted wetlands (internal and/or external). The URI Environmental Data Center then joined this dataset with the Juris, Towns, and Rarespecies coverages available though the Rhode Island Geographic Information System (RIGIS). This completed the development of the matrix.
The following metadata records document the components used to build the matrix.
coastal.met – describes the baseline coastal wetland data for Narragansett Bay
degraded.met – describes the internally impacted wetlands for Narragansett Bay
externals.met – describes the external impacts on freshwater and coastal wetlands in Narragansett Bay
lulc–500.met – describes the 500–foot buffer delineation of land use, which is where the freshwater wetlands were obtained
Summary of the Wetland Matrix Attributes
Summary of Field Names in the Wetland Matrix File
Field Name Descriptive Name Description Site__ Site Number This is a unique identifier for each polygon that was mapped from the original Matrix file. This ID is used in all of the reporting functions of the tool. Acres Size of Site Areal extent (size) of the site in acres. Restcode Wetland Classification Code These codes are based on the U.S. Fish and Wildlife Service's Classification of Wetlands and Deepwater Habitats of the United States (Cowardin and others, 1979) see below for full description Internal Internal Impairments Impairments which are internal to the wetland site (e.g., tidal restriction). See below for a full description. External External Land Use Impacts Potential impacts from land uses outside of the sites in a 500 meter buffer (e.g., golf course). Complex_nu Complex Number Individual wetland polygons (sites) were grouped into potential restoration project areas or "complexes" based on their location, type of impairment, ecology, field conditions, and other variables. See below for a full description of the complex codes. Town Town The town that the site falls within. Sub_basin Watershed Subbasin The watershed subbasin that the site falls in. Basin Watershed Basin The watershed basin that the site falls in. Rare_sp Rare Species If Y = yes then rare species are known to be present on the site. Blank cell means unknown rare species status.
Wetland Classification Code Descriptions (Field name = "Restcode")
These codes are based on the U.S. Fish and Wildlife Service's Classification of Wetlands and Deepwater Habitats of the United States (Cowardin and others, 1979) which is described below.
E2EM1Pd6 = Estuarine Intertidal Emergent Persistent Ditched Brackish
The first character is the system:
E = Estuarine
M = Marine
The second number is the subsystem:
1 = Subtidal
2 = Intertidal
The third and fourth characters comprise the Class
AB = Aquatic Bed
UB = Unconsolidated Bottom
EM = Emergent
RF = Reef
RS = Rocky Shore
SS = Scrub–Shrub
US = Unconsolidated Shore
SB = Streambed
The fifth number is the sub–class:
AB1 = Aquatic Bed, Algal
AB3 = Aquatic Bed, Rooted Vascular
AB4 = Aquatic Bed, Floating Vascular
UB = Has no subclasses
EM1 = Emergent, Persistent
EM5 = Emergent, Phragmites australis
RF2 = Reef, Mollusc
RS1 = Rocky Shore, Bedrock
RS2 = Rocky Shore, Rubble
SS1 = Scrub Shrub, Broad Leaved Deciduous
US1 = Unconsolidated Shore, Cobble–Gravel
US2 = Unconsolidated Shore, Sand
US3 = Unconsolidated Shore, Mud
The sixth character is the water regime:
L = Subtidal
N = Tidal, Regularly Flooded
P = Tidal, Irregularly Flooded
M = Tidal, Irregularly Exposed
If the CODE is E1AB3L or M1AB3L, then the seventh character is a special modifier for percent cover:
e = percent cover cannot be determined; eelgrass signature is present, but there is
d = 70% to 100% cover
c = 40% to 69% cover
b = 10% to 39% cover
a = < 10% cover
If the CODE is NOT E1AB3L or M1AB3L, then the 7th character is a special modifier for human impact:
d = ditched
h = diked / impounded
r = artificial substrate
x = excavated
The eigth character is the water chemistry:
1–6 = Brackish
1 = Hyperhaline
2 = Euhaline
3 = Mixohaline
4 = Polyhaline
5 = Mesohaline
6 = Oligohaline
Complex Number (Field Name = "complex_nu")
To identify focus areas for restoration efforts, potential coastal wetland restoration sites were grouped according to complexes by the University of Rhode Island Environmental Data Center, Narragansett Bay Ecosystem Program, and Save the Bay. A new classification for complex was created by selecting all potential wetland restoration polygons, including all former coastal wetland polygons (Type 1 sites), coastal wetland polygons with internal sources of degradation (Type 2 sites), and coastal wetland polygons with potential external sources of degradation. These individual wetland polygons were then grouped into potential restoration project areas or "complexes" based on their location, type of impairment, ecology, field conditions, and other variables. The wetland polygons were then coded with the complex number, so that all potential restoration sites within one complex have the same complex code. This process identified 236 wetland restoration complexes for the Narragansett Bay Estuary (Helen Cottrell, Narragansett Bay Estuary Program, pers. comm. 2003).
Narragansett Bay Wetland Complexes
Code Definition nwp West Passage nwr Warren River ris Rhode Island Sound (Newport) nsk Sakonnet River nsr Seekonk River ntr Taunton River nkr Kicamuit River nlm Long Meadow, Warwick nlr Lee River nmc Mill Creek nmg Mill Gut, Bristol nmh Mount Hope Bay nnr Narrow River npr Palmer River npv Providence River nep East Passage ngb Greenwich Bay nhc Hundred Acre Cove nar Assonet River nbb Barrington Beach nbh Bristol Harbor nbn Bristol Narrows nbr Barrington River ncc Church Cove, Bristol ncr Cole River
On–Site / Internal Impacts
The "1" in the code designates Type 1 wetland sites, which are former estuarine wetlands that are now changed in some way that makes them not connected to the original saltwater source. The "2" in the code designates Type 2 sites, which are existing estuarine wetlands but are functionally impaired. Blanks in this field represent sites that are not internally impacted.
Internal Wetland Impacts
Code Definition 1f Filled 1fph Filled/Phragmites–dominated 1fsp Filled/Dredge spoil 1d Effectively drained 1su Submerged 1w Palustrine wetland 1x Excavated palustrine wetland 2r Tidally restricted 2rs Severely tidally restricted (Phragmites >30% cover) 2d Significant ditching 2h Diked/impounded 2f Minor filling 2fs Minor filling/Dredge spoil 2v Vegetation change/Phragmites–dominated 2vi Vegetation change/Iva–dominated 2x Excavation < blank> None
Restoration Actions Needed
For the Type 2 sites, the restoration action that is needed can be interpreted from the type of internal impact that is in place at the site.
Code Definition 2r Reduce tidal constriction 2rs Reduce constriction and remove Phragmites 2d Remove large ditches 2h Remove dike 2f Remove minor fill 2fs Remove dredge spoil 2v Remove Phragmites 2vi Restore sheet flow 2x Fill and re–contour excavation < blank> None
Off–Site / External Impacts
Surrounding land use/land cover was analyzed within a 500–foot buffer around each site to determine possible off–site impacts.
Definition of Off–Site / External Impact Codes
Code Definition Eis Impervious surfaces Ela Lawns Egc Golf courses Ein Industrial plants Ejk Junkyards Edf Dairy farms Ecr Cropland Esg Sand and gravel operations Ees Erosion and sedimentation (as from earthwork or bank erosion) < blank> None
For further details on the data, please see the metadata records referenced above. These are available through RIGIS (www.edc.uri.edu/rigis) and on the Salt Marsh Site Selection Tool CD-ROM, which can be requested from www.edc.uri.edu/restoration/html/spatial/modlsalt.htm.