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2011 Rhode Island Soil Survey Update

2011 Rhode Island Soil Survey Update: First Official Subaqueous Soil Survey in the U.S.

In recent years, the Rhode Island Natural Resources Conservation Service has been at the forefront of soil survey mapping efforts in the shallow sub-tidal environment (subaqueous soils), and along the coastal zone (Coastal Zone Soil Survey).  Until recently, the National Cooperative Soil Survey only mapped soils to the edge of the land\water divide.  In 1999, the definition of soils was extended to include areas covered by shallow (~<5m) water, the general limit of rooted submersed aquatic vegetation.  For the Rhode Island (the Ocean State), this significantly expanded our mapping area.  With the expansion of shellfish aquaculture farming, eelgrass and coastal restoration efforts, and increased pressure from development in Rhode Island’s coastal areas, the addition of soils information for shallow water areas and the coastal zone was determined to be a priority for coastal and marine spatial planning efforts.  After six years of research by the RI Natural Resources Conservation Service (NRCS) in association with the University of Rhode Island and the Rhode Island Mapping Partnership for Coastal Soils and Sediment (www.MapCoast.org), Rhode Island has become the first state to have an officially published coastal zone soil survey. 

Phase I (see map right) of the update to the Rhode Island Soil Survey includes new subaqueous soil mapping and data and a re-map of the coastal areas (dunes, marshes, beaches, and urban areas) for the southern coast of Washington County, including the major coastal ponds (Trustom, Cards, and the smaller ponds will be completed in 2011).  Ten new subaqueous soil series and six coastal series were established describing sandy soils, highly fluid soils, bouldery soils, and soils with significant amount of sulfides.  Thirty seven new soil map units were established to re-map the submerged soils, dunes, marshes, and beaches along the south shore coastal zone. In addition to the soil polygons, new soil spot and line symbols were also developed to provide additional data such as the location of shoreline protection structures, and vernal pools (see Table 1). The update also included joining the soils data to adjacent states to complete a seamless survey and fixing some errors identified in the existing digital data.  Figure 1 below is a comparison of the old vs. new RI soils data.

Phase II of the Rhode Island Subaqueous Soil Survey is planned to include Point Judith north to Greenwich Bay, also several large fresh water ponds will also be mapped. Phase II is scheduled to be completed in 2011. From there it is hoped the remainder of the Rhode Island coastal zone can be completed. 

Use of this data:

In 2004 the RI NRCS adopted a “Working Waters” element into their strategic plan and began to expand their work and technical expertise to address coastal issues in the Ocean State including declining sea-grass in the bays and salt ponds, eutrophication and anoxia causing fish kills, tidal marsh degradation due to improperly engineered structures, and numerous other issues that could be tied to the terrestrial landscape. When the NRCS began to focus work in the coastal zone, a gap in the key dataset that the NRCS uses for land-use planning was identified: the soil survey did not include information for coastal or shallow water soils. The RI Soil Survey Program responded to this data gap by setting a coastal zone soil survey as a top priority and the formation of MapCoast followed.

Because costs associated with coastal restoration, aquaculture, and benthic habitat restoration are often very high compared with terrestrial projects, the need for accurate maps and data is especially important to identify areas for restoration and preservation. Marine spatial planning is currently a priority for other agencies in deeper marine waters, however marine studies often do not include detailed information on shallow and coastal areas. It is hoped this new type of soil spatial maps and data will fill this data gap and be used for projects just as the soil survey is currently used on land. Research is currently underway to build soil interpretations for various subaqueous needs. Potential interpretations and uses of this new data include:

  • Marine Spatial Planning - requires detailed and accurate seamless maps
  • Seagrass (Eelgrass) Restoration Potential
  • Oyster and Shellfish Restoration Potential
  • Aquaculture Farming Suitability
  • Dredge disposal concerns (acid sulfate weathering potential)
  • Estuarine Health Analysis
  • Beach and dune stabilization and replenishment
  • Standard soil interpretations for septic systems (coastal soils), hydric soils, hydrologic soil groups, etc.
  • Numerous other interpretations are being studied.
Accessing the New Rhode Island Soil Data:

The new RI soil data is available in multiple formats via:
Web Soil Survey: http://websoilsurvey.nrcs.usda.gov/ (online mapping of specified areas including interpretive maps)
Soil Data Mart: http://soildatamart.nrcs.usda.gov/ (download complete RI soils tabular and spatial data)
RIGIS: www.edc.uri.edu/rigis/ (Rhode Island Geographic Information Systems)
MapCoast: www.mapcoast.org (includes additional shallow water data such as bathymetry, geology, and habitat data) data not available yet check back.

For more information about subaqueous soils visit: http://nesoil.com/sas
Contact: Jim Turenne 401-822-8830 or jim.turenne@ri.usda.gov

Figure 1: Comparison of the New 2011 RI Soils and the 1996 soils

Table 1: List of new soil series and map units added to the new RI Soil Survey Data

Subaqueous Soils: soils permanently covered with saline water for more than 21 hours per day (Note: phases of each series defined by average water depth, dredge phases, and surface rock fragments).

Soil Series

Map Unit Names (phases)

Brief Description

Anguilla

Anguilla mucky sand, 0 to 1 meter water depth
Anguilla mucky sand, 1 to 2 meter water depth
Anguilla mucky sand, 2 to 3 meter water depth

Subaqueous soils formed in sandy marine deposits over sandy and gravelly outwash.

Billington

Billington silt loam, 0 to 1 meter water depth

Subaqueous soils formed in highly fluid silt loam surface underlain by organic material.

Fort Neck

Fort Neck mucky silt loam, 0 to 1 meter water depth
Fort Neck mucky silt loam, 1 to 2 meter water depth
Fort Neck mucky silt loam, 2 to 3 meter water depth

Subaqueous soils formed in highly fluid silt loam surface underlain by sandy marine deposits.

Marshneck

Marshneck loam, 1 to 2 meter water depth

Subaqueous soils formed in sandy marine sediments on flood tidal delta slopes.

Massapog

Massapog fine sand, 0 to 1 meter water depth
Massapog fine sand, 1 to 2 meter water depth
Massapog fine sand, 2 to 5 meter water depth, dredged
Massapog fine sand, intertidal

Subaqueous soils formed in fine sandy marine sediments on flood tidal deltas.

Nagunt

Nagunt sand, 0 to 1 meter water depth
Nagunt sand, 2 to 5 meter water depth, dredged
Nagunt sand, sloping, 1 to 2 meter water depth

Subaqueous soils formed in sandy marine deposits on washover fans and storm surge platforms.

Napatree

Napatree sand, 0 to 1 meter water depth, bouldery
Napatree sand, 0 to 1 meter water depth, extremely bouldery

Subaqueous soils formed in fluid loamy marine sediments underlain by till.

Pishagqua

Pishagqua mucky silt loam, 0 to 1 meter water depth
Pishagqua mucky silt loam, 1 to 2 meter water depth
Pishagqua mucky silt loam, 2 to 3 meter water depth
Pishagqua mucky silt loam, 2 to 5 meter water depth, dredged

Subaqueous soils formed in thick highly fluid silt loam marine sediments in low energy basins.

Rhodesfolly

Rhodesfolly fine sand, 0 to 1 meter water depth
Rhodesfolly fine sand, 1 to 2 meter water depth

Subaqueous soils formed in coarse sandy marine deposits in open bays and inlets.

 Coastal Soils mapped on the dunes, marshes, beaches and human made land.

Soil Series

Map Unit Names (phases)

Brief Description

Beach Phases

Beaches, bouldery surface

Beaches, cobbly surface

Beaches, Sandy Surface

Non-soil beach deposits, phases defined by dominant surface texture and fragment class.

Bigapple

Bigapple sand, 0 to 8 percent slopes

Well drained soils formed in sandy dredge material

Fortress

Fortress sand, 0 to 3 percent slopes

Moderately well drained soils formed in dredge matieral.

Hooksan

Hooksan sand, 3 to 8 percent slopes

Hooksan sand, 8 to 15 percent slopes

Excessively drained soils formed in eolian and/or washover material

Matunuck

Matunuck Mucky Peat

Tidal marsh soil formed in 8-16 inches of peat underlain by sand.

Pawcatuck

Pawcatuck mucky peat

Tidal marsh soil formed in 16-51 inches of peat underlain by sand.

Sandyhook

Sandyhook mucky peat, 0 to 3 percent slopes

Tidal marsh soil formed in 0-8 inches of peat underlain by sand.

Succotash

Succotash sand, 0 to 3 percent slopes

Moderately well drained soil formed in eolian and/or washover sands on back barriers.

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