Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Generally.
Before conducting a field evaluation, the designer shall confer
with the local unit of government to determine the requirements and scope of
the evaluation, dependent upon system size, soil conditions, and other
applicable factors. At a minimum, the requirements in this part must be
met.
Subp. 2.
Property marks.
Property lines must be identified as acceptable to the owner.
Site improvements, required setbacks, and easements must be identified,
located, and marked.
Subp.
3.
Site area.
A general evaluation and description of the proposed soil
dispersal area, including a general geomorphic description, current land use,
and past land use, if known, must be provided.
Subp. 4.
Surface features.
The following surface features must be identified and
described:
A. the dominant
vegetation;
B. evidence of
disturbed or compacted soil or flooding or run-on potential; and
C. landscape position, including landform,
slope gradient, slope direction, and surface morphometry as described in the
Field Book for Describing and Sampling Soils Version 2.0, September 2002,
developed by the National Soil Survey Center and Natural Resources Conservation
Service of the United States Department of Agriculture. The field book is
incorporated by reference, is not subject to frequent change, and is available
through the Minitex interlibrary loan system.
Subp. 5.
Soil pits.
A. Soil pits are required to investigate the
soil for MSTS design. The required number of soil pits to adequately define the
limiting layer and soil dispersal system sizing must be determined by
professional judgment based on the size of the area and consistency of the soil
and must be approved by the local unit of government.
B. The qualifying soil pits or borings to be
used for the MSTS design must be located on or near the borders of the proposed
soil treatment and dispersal area. Soil pits must be dug outside the soil
dispersal area if possible. The soil must be observed and described to a depth
of at least three feet below the proposed depth of the system. Other soil
observations are allowed to be made to supplement the required soil pit
information.
C. Underground
utilities must be located before soil observations are undertaken. Required
safety precautions must be taken before entering soil pits.
Subp. 6.
Soil
description.
A. The soil properties and
features in subitems (1) to (13) must be described according to Field Book for
Describing and Sampling Soil, version 2, Natural Resources Conservation
Service, United States Department of Agriculture (September 2002), for each
soil horizon at each qualifying soil pit. The field book is incorporated by
reference under subpart
4, item C.
(1) Matrix soil color.
(2) Soil features that have different colors
from the matrix color, including but not limited to clay films, organic stains,
silt coats, nodules, and concretions.
(3) Abundance, size, color, and contrast of
redoximorphic features.
(4) Soil
texture, with modifiers.
(5) Grade,
size, and shape of soil structure.
(6) Moist soil consistence.
(7) Abundance and size of rock
fragments.
(8) Abundance and size
of roots.
(9) Horizon boundary
conditions.
(10) Parent
materials.
(11) Pores, quantity and
size.
(12) Quantity of boulders and
tree stumps affecting construction.
(13) Any other characteristic or feature that
affects permeability of the soil or treatment of sewage effluent.
B. The depth of bedrock, if
encountered, must be determined by requirements of part
7080.1100, subpart
8.
C. The elevation of standing water evident in
any soil pit must be identified.
D.
The soil must not be described when frozen, at an improper moisture content, or
under poor light conditions.
Subp.
7.
Method.
Hydraulic conductivity testing of the soil must be employed,
along with a determination of the soil's texture, structure, and consistence,
to determine the loading rate of effluent to the soil. The frequency of the
observations and measurements must be determined by the professional judgment
of the designer, dependent on the variation in soil conditions and the system
size, with the frequency of the observations and measurements approved by the
local unit of government.
Subp.
8.
Comparison with soil survey.
All field soil information gathered must be compared with soil
survey information. Any discrepancies shall be identified.
Statutory Authority: MS s
115.03;
115.55
