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Anguilla

Soil Map Unit Description from the RI Soil Survey Report

WAa0 - Anguilla mucky sand, 0 to 1 meter water depth

This subaqueous soil occurs on shoals, coves, and submerged mainland beaches adjacent to the shoreline of coastal lagoons and bays. Areas are irregular in shape and range from 0.4 to 25 hectares (1 to 64 acres).

Typically, this soil has a slightly fluid, black mucky sand surface layer, 10 to 30 cm thick derived from sands eroded from the shoreline and re-deposited in the estuarine environment. The subsoil is olive brown loamy sand, 20 to 35 cm thick derived from marine or estuarine deposits. The substratum is olive brown, gravelly sand derived from outwash. The substratum often contains brown oxidized soils in coarse textured materials due to fresh groundwater inputs.

This soil is permanently submerged beneath up to 1 meter of salt or brackish water, though may be exposed in small areas at extreme low tides. All horizons have a neutral pH in place and a strongly acidic pH after oxidation.

These soils, when adjacent to the shoreline, may be a source of freshwater input into estuary waters and represent a connection between groundwater and marine waters due to coarse textures and high saturated conductivity. These soils may contain sulfidic materials in the soil profile that if drained or dredged and exposed to air will oxidize and create acid sulfate drainage.

Included with this soil in mapping are small areas of Fort Neck silt loam in low energy areas where marine silts and organic material accumulate on the soil surface. Billington soils may also be found in this map unit in areas where a bog or marsh has been submerged by sea level rise and covered with sands due to erosion from mainland beaches. Pishagqua soils may be found in this map unit in mainland coves and lagoon bottom landscapes. Napatree soils may also be found in this map unit adjacent to landscapes dominated by till material (mainland coves and mainland submerged beaches). The substratum may vary from extremely gravelly to non-gravelly in this map unit. Some areas (usually adjacent to beaches, cobble surface map units) have extremely cobbly and gravelly surfaces. Included areas make up about 15 percent of the map unit.

This soil supports submerged aquatic vegetation, approximately 6% of this map unit is covered with (2012) SAV. The area is used by recreational and commercial fishermen for shell fishing and harvesting of crabs. This map unit is well suited for bottom gear aquaculture. Oysters and other shellfish are commonly found in this map unit.
 

Link to Official Series Description - Anguilla | Soil Profile Photo of Anguilla Soil
 

WAa1: Anguilla mucky sand, 1 to 2 meter water depth 


This subaqueous soil occurs on shoals, coves, and submerged mainland beaches adjacent to the shoreline of coastal lagoons and bays. Mapped areas are irregular in shape and range from 0.4 to 29 hectares (1 to 72 acres).

Typically, this soil has a slightly fluid, black mucky sand surface layer, 10 to 30 cm thick derived from sands eroded from the shoreline and re-deposited in the estuarine environment. The subsoil is olive brown loamy sand, 20 to 35 cm thick derived from marine or estuarine deposits. The substratum is olive brown, gravelly sand derived from outwash. The substratum often contains brown oxidized soils in coarse textured materials due to fresh groundwater inputs.

This soil is permanently submerged beneath 1 to 2 meters of salt or brackish water. All horizons have a neutral pH in place and a strongly acidic pH after oxidation.

These soils, when adjacent to the shoreline, may be a source of freshwater input into estuary waters and represent a connection between groundwater and marine waters due to coarse textures and high saturated conductivity. These soils may contain sulfidic materials in the soil profile that if drained or dredged and exposed to air will oxidize and create acid sulfate drainage.

Included with this soil in mapping are small areas of Fort Neck silt loam in low energy areas where marine silts and organic material accumulate on the soil surface. Billington soils may also be found in this map unit in areas where a bog or marsh has been submerged by sea level rise and covered with sands due to erosion from mainland beaches. Pishagqua soils may be found in this map unit in mainland coves and lagoon bottom landscapes. Napatree soils may also be found in this map unit adjacent to landscapes dominated by till material (mainland coves and mainland submerged beaches). The substratum may vary from extremely gravelly to non-gravelly in this map unit. Some areas (usually adjacent to beaches, cobble surface map units) have extremely cobbly and gravelly surfaces. Included areas make up about 15 percent of the map unit.

This soil supports submerged aquatic vegetation (SAV) and benthic marine habitats. The area is used by recreational and commercial fishermen for shellfishing and harvesting of crabs. Some areas are vegetated with native algae and eelgrass (Zostera marina). SAV cover is generally less than 1 percent for this map unit (2012 data).

Link to Official Series Description - Anguilla | Soil Profile Photo of Anguilla Soil
 

WAa2: Anguilla mucky sand, 2 to 3 meter water depth
 

This subaqueous soil occurs on mid-lagoon channels in coastal lagoons and bays. Mapped areas are linear in shape and range from 1 to 6 hectares (5 to 16 acres).

Typically, this soil has a thin, slightly fluid, black mucky sand surface layer, 5 to 10 cm thick. The substratum is olive brown, gravelly sand derived from outwash. Tidal currents through these areas keep fine particles from settling to the bottom, often leaving a gravelly soil surface.

This soil is permanently submerged beneath greater than 2 meters of salt or brackish water. All horizons have a pH of neutral and a pH of ultra acid through strongly acid after 8 weeks incubation.

Included with this soil in mapping are small areas of Fort Neck silt loam in low energy areas where marine silts and organic material accumulate on the soil surface. Napatree may also be found in this map unit adjacent to landscapes dominated by till material (mainland coves and mainland submerged beaches). The substratum may vary from extremely gravelly to non-gravelly in this map unit. These areas often have extremely cobbly and gravelly surfaces. Included areas make up about 5 percent of the map unit.

Submerged aquatic vegetation (mostly Eelgrass) for this map unit is about 4% (2012 data). Some areas have thick macro-algae cover. This map unit is generally not suited for bottom gear aquaculture due to water depth.

Link to Official Series Description - Anguilla | Soil Profile Photo of Anguilla Soil
 

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