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FortNeck Subaqueous Soils

Soil Map Unit Description from the RI Soil Survey Report (2010 Update)

WFn0: Fort Neck silt loam, 0 to 1 meter water depth (2010 Update for the RI Coastal Zone Soil Survey Phase I - please download the latest copy of the spatial data).

This subaqueous soil is found in low energy basins and mainland coves of coastal lagoons and bays. Areas are irregular in shape and range in size from 0.5 to 73 hectares (1 to 180 acres). Slope ranges from 0 to 2 percent.

Typically, the surface layer is fluid, black silt loam, 25 to 50 cm thick, derived from marine and\or estuarine silts. The substratum is olive gray sandy loam derived from submerged Pleistocene-aged glacial outwash or till or estuarine sands to a depth of 200 cm or more.

This soil is permanently submerged beneath 0 to 1 meter of salt or brackish water that undergoes minimal currents and wave action. All horizons have a slightly alkaline pH in place, and may have an acidic pH after oxidation. Sulfidic materials occur within 50 cm of the soil surface, and are typically confined to the estuarine silts. These highly sulfidic materials, if drained or dredged and exposed to air, will oxidize and create acid sulfate drainage.

Included with this map unit are small areas of Pishagqua soils found in depressions or at a greater distance from the shoreline. Small areas of Anguilla and Napatree soils are found in this unit close to the shoreline. Small inclusions of Billington soils are also found on lagoon bottoms and in coves where soils are underlain by organic material. Included areas make up about 15 percent of the map unit.

Fort Neck soils provide important eelgrass (Zostera marina) habitat as well as habitat for fish and shellfish. This soil is also used for the harvest of crabs and aquaculture.

Link to Official Series Description - Fort Neck | Soil Profile of Fort Neck Series

UPDATE: The Coastal Zone of Rhode Island is currently being updated and re-mapped, for more information on this update visit: www.mapcoast.org

 

WFn1: Fort Neck silt loam, 1 to 2 meter water depth

This subaqueous soil is found in low energy basins and mainland coves of coastal lagoons and bays. Areas are irregular in shape and range in size from 0.5 to 36 hectares (1 to 90 acres). Slope ranges from 0 to 2 percent.

Typically, the surface layer is fluid, black silt loam, 25 to 50 cm thick, derived from marine and\or estuarine silts. The substratum is olive gray sandy loam derived from submerged Pleistocene-aged glacial outwash or till or estuarine sands to a depth of 200 cm or more.

This soil is permanently submerged beneath 1 to 2 meters of salt or brackish water that undergoes minimal currents and wave action. All horizons have a slightly alkaline pH in place, and may have an acidic pH after oxidation. Sulfidic materials occur within 50 cm of the soil surface, and are typically confined to the estuarine silts. These highly sulfidic materials, if drained or dredged and exposed to air, will oxidize and create acid sulfate drainage.

Included with this map unit are small areas of Pishagqua soils found in depressions or at a greater distance from the shoreline. Small areas of Anguilla and Napatree soils are found in this unit close to the shoreline. Small inclusions of Billington soils are also found on lagoon bottoms and in coves where soils are underlain by organic material. Included areas make up about 15 percent of the map unit.

Fort Neck soils provide important eelgrass (Zostera marina) habitat as well as habitat for fish and shellfish. This soil is also often used for the harvest of crabs and aquaculture.

Link to Official Series Description - Fort Neck | Soil Profile of Fort Neck Series

UPDATE: The Coastal Zone of Rhode Island is currently being updated and re-mapped, for more information on this update visit: www.mapcoast.org

 

WFn2: Fort Neck silt loam, 2 to 3 meter water depth

This subaqueous soil is found in low energy basins and mid lagoon channels of coastal lagoons and bays. Areas are irregular in shape and range in size from 2 to 12 hectares (5 to 30 acres). Slope ranges from 0 to 2 percent.

Typically, the surface layer is fluid, black silt loam, 25 to 50 cm thick, derived from marine and\or estuarine silts. The substratum is olive gray sandy loam derived from submerged Pleistocene-aged glacial outwash or till or estuarine sands to a depth of 200 cm or more.

This soil is permanently submerged beneath 2 to 3 meters of salt or brackish water. All horizons have a slightly alkaline pH in place, and may have an acidic pH after oxidation. Sulfidic materials occur within 50 cm of the soil surface, and are typically confined to the estuarine silts. These highly sulfidic materials, if drained or dredged and exposed to air, will oxidize and create acid sulfate drainage.

Included with this map unit are small areas of Pishagqua soils found in depressions or at a greater distance from the shoreline. Small areas of Anguilla and Napatree soils are found in this unit. Included areas make up about 15 percent of the map unit.

This soil generally does not support rooted vegetation. Some areas have native algae cover. Vegetative cover is less than 10 percent.

Link to Official Series Description - Fort Neck | Soil Profile of Fort Neck Series

 

UPDATE: The Coastal Zone of Rhode Island is currently being updated and re-mapped, for more information on this update visit: www.mapcoast.org