PLYMOUTH COUNTY, MASSACHUSETTS SOIL SURVEY UPDATE
Saco Soils: Very deep, level, very poorly drained soil formed in silty alluvial deposits. Saco soils are on the lowest lying parts of flood plains and are subject to frequent flooding.
to Official Series Description
Saco Pedon Description 2300501
Saco Pedon Description 2300502
Saco Pedon Description 2300503
Unit (s): 005A - Saco mucky silt loam, 0 to 2 percent slopes.
Taxonomic Classification: Coarse silty, mixed, nonacid, mesic, Fluvaquntic Humaquepts.
Drainage Class: Very poorly drained.
Parent Material: Recent alluvium, organic and silty mineral deposits.
Permeability: Moderately rapid in the organic surface layer, and slow to moderately slow in the substratum.
Available Water Holding Capacity: High.
Soil Reaction: Strongly acid to neutral to 30 inches, and moderately acid to neutral below.
Depth to Bedrock: Greater than 65 inches.
Seasonal High Watertable: Depth: + 3.0 to 0.5 feet below the surface. Type: Apparent.
Months: January to December.
Hydrologic Group: D.
Hydric Soil: Yes.
Flooding/Ponding Potential: Frequency and Type: Frequently flooded. Duration and Months: Long, December to April.
Potential Inclusions: Scarboro, Swansea and Freetown soils are similar inclusions. Poorly drained Limerick and Walpole soils are on higher elevations. Moderately well drained Winnoski and Eldridge soils are on upland areas.
Agriculture: Poorly suited for most agricultural uses mainly due to wetness and flooding.
Woodland: Poorly suited due to wetness.
Development: Poorly suited due to seasonal high watertables at or near the surface for prolong periods of time.
Plymouth County Map Unit Description:
5A - Saco mucky silt loam, 0 to 2 percent slopes.
This very deep, nearly level, very poorly drained soil formed in silty alluvial deposits. Saco soils are on the lowest lying parts of flood plains and are subject to frequent flooding.
Saco soils typically have a very dark gray mucky silt loam surface layer 12 inches thick. The substratum from 12 to 32 inches is mottled gray silt loam, from 32 to 48 inches is gray silt loam, and from 48 to 60 inches is gray, loose, stratified sand.
In many areas the sandy substratum is within 40 inches of the surface. Where mapped along the Taunton and Nemasket rivers, the substratum consists of varved silt-loam to silty clay loam textures, lacking sandy strata's and permeability is slow to very slow in the substratum.
Included with this soil in mapping are areas of Freetown and Swansea soils on similar landscape positions. Also included are narrow areas of Limerick and Winooski soils at slightly higher elevations.
Most areas of this soil are in sedges or wetland shrubs and grasses.
Due to the hazard of flooding and the seasonal high water table this soil is very poorly suited for crop production or pastureland.
This soil is very poorly suited for woodland productivity because of flooding, excess soil moisture, high seedling mortality and the hazard of windthrow. Optimum growth and survival is not expected. On site investigations may reveal that tree plantings are practical with special treatment.
Saco soils are hydric soils associated with wetlands. Wetlands are protected from disturbance by State and Federal regulations. Development activities within these areas typically require special permits prior to disturbance. This soil is not suited to development due to flooding and wetness. This soil is unsuitable for building sites and septic tank absorption fields because of the flooding hazard and seasonal high water table. Constructing roads on raised, coarse textured fill material and providing adequate side ditches and culverts will help protect them from flood damage. This soil is sufficiently wet under undrained conditions to support the growth and regeneration of wetland plants.
This soil is well suited to wetland wildlife. The native plant communities common to this soil provide adequate food and cover for wildlife communities.
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