Description: Septic tank absorption fields are areas in which effluent from a septic tank is
distributed into the soil through subsurface tiles or perforated pipe. Only that
part of the soil between depths of 24 and 60 inches is evaluated. The ratings
are based on the soil properties that affect absorption of the effluent,
construction and maintenance of the system, and public health. Saturated
hydraulic conductivity (Ksat), depth to a water table, ponding, depth to
bedrock or a cemented pan, and flooding affect absorption of the effluent.
Stones and boulders, ice, and bedrock or a cemented pan interfere with
installation. Subsidence interferes with installation and maintenance.
Excessive slope may cause lateral seepage and surfacing of the effluent in
downslope areas.
Some soils are underlain by loose sand and gravel or fractured bedrock at a
depth of less than 4 feet below the distribution lines. In these soils the
absorption field may not adequately filter the effluent, particularly when the
system is new. As a result, the ground water may become contaminated.
Rating class terms indicate the extent to which the soils are limited by all of
the soil features that affect the specified use. "Not limited" indicates that the
soil has features that are very favorable for the specified use. Good
performance and very low maintenance can be expected. "Somewhat
limited" indicates that the soil has features that are moderately favorable for
the specified use. The limitations can be overcome or minimized by special
planning, design, or installation. Fair performance and moderate
maintenance can be expected. "Very limited" indicates that the soil has one
or more features that are unfavorable for the specified use. The limitations
generally cannot be overcome without major soil reclamation, special design,
or expensive installation procedures. Poor performance and high
maintenance can be expected.
An aggregated rating class is shown for each map unit. Other components
with different ratings may be present in each map unit. The ratings for all
components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil
Survey. Onsite investigation may be needed to validate these interpretations
and to confirm the identity of the soil on a given site.
Copyright Text: Great Smoky Mountains National Park