The following is a map unit description from the "Soil Survey of Norfolk and Suffolk Counties, Massachusetts (Peragallo, 1989)"
Ue-Udorthents, wet substratum. This map unit consists of filled areas that were previously tidal marshes, river flood plains, bays, harbors, and swamps (fig. 10). The fill consists of rubble, refuse, and mixed soil material, typically, sand, gravel, and channel dredgings. Depth of the fill ranges from 2 to 20 feet or more. Areas of these soils are most extensive along Boston, Dorchester, and Quincy Bays and adjacent to the Charles and Neponset Rivers. Smaller areas are scattered throughout the survey area. Areas of these soils are irregular in shape and range from 6 to 600 acres.
Typically, the surface layer is very dark gray fine sandy loam about 14 inches thick. The substratum in the upper part is dark grayish brown fine sandy loam and in the lower part is very dark gray silt mixed with oyster shells and other debris. It extends to a depth of 82 inches. Below that, it is underlain by a preexisting tidal mud flat. A distinct sulfide odor emanates from the lower part of the substratum. In some areas the original surface layer has been removed.
Included with this map unit are small areas of Urban land and Ipswich soils. These areas are typically less than 2 acres in size, and make up about 5 percent of the map unit.
Permeability: Moderate or slow.
Available water capacity: Low or moderate.
Runoff is slow, and water tends to pond on the surface after intensive rain. The seasonal high water table is in the lower part of the substratum, commonly within 3 to 5 feet of the surface.
If these areas are used as building sites, extensive onsite investigation is needed and pilings are typically used in preparing foundations. Vegetable gardens generally can be planted if individual areas are tested for reaction, nutrients, and metal content.
Onsite investigation is needed to determine the suitability of these soils for any use.
These soils have not been assigned to a capability subclass.
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