(A) Soil and site evaluations must be conducted for MSTS design. The evaluations must be conducted according to this section and § 52.09. Evaluations must identify and delineate an initial and replacement soil treatment and dispersal area with appropriate system boundaries.
(B) A preliminary evaluation for midsized subsurface sewage treatment systems shall consist of determining:
(1) The design flow and anticipated effluent concentrations of biochemical oxygen demand, total suspended solids, and fats, oils, and grease, and inputs of non-domestic waste.
(2) Whether the location of water supply wells impacts the location of the system due to setback constraints.
(3) Whether building improvements will be within 50 feet of the proposed soil treatment and dispersal area.
(4) Whether buried water supply pipes will be within 50 feet of the proposed system.
(5) Whether easements will be within 50 feet of the proposed system.
(6) Whether the ordinary high water level of public waters will be within 500 feet of the proposed soil treatment and dispersal area and if so, a preliminary assessment of phosphorus impacts to the surface water.
(7) Whether the system will be located in a floodplain and the system location in relation to the 100-year flooding elevation from published data if available or data that is acceptable to the Department or local unit of government.
(8) The required setbacks from the proposed soil treatment and dispersal system.
(9) The soil survey information on the proposed soil dispersal area, including the soil map, map units, landscape position,’parent material, flooding potential, slope range, periodically saturated soil level, depth to bedrock, texture, color, and structure of soil horizons, and permeability of soil horizons.
(10) A geocode or property identification number.
(11) The names of the property owners; and
(12) The location of the system on a United States Geological Survey quadrangle map of the proposed soil treatment and dispersal area and the area within one mile.
(C) Before conducting a field evaluation, the designer shall confer with the Department or 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 section must be met:
(1) Property lines must be confirmed in the field using the most recent document source. Site improvements, required setbacks, and easements must be identified, located, and marked.
(2) 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.
(3) 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.
(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.
(D) The required number of soil pits to adequately characterize the soil on the proposed site must be determined by the professional judgment of the designer as based on the size of the area, consistency of the soil, and approved by the Department or local unit of government.
(E) The qualifying soil observation pits to be used for the MSTS design must be located on or near the borders of the proposed soil treatment and dispersal area. Soil observation 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 observation pits are allowed to supplement the required soil observation pit information.
(F) Underground utilities must be located before soil observations are undertaken. Required safety precautions must be taken before entering soil observation pits.
(G) The following soil observations must be made:
(1) The soil properties and features described in items (F)(1)(a) to (m) must be described according to the Field Book for Describing and Sampling Soils, which is incorporated by reference under § 52.02.
(a) Matrix soil color.
(b) Soil features that have different colors from the matrix color, including, but not limited to, clay films, organic stains, silt coats, nodules, and concretions.
(c) Abundance, size, color, and contrast of redoximorphic features.
(d) Soil texture, with modifiers.
(e) Grade, size, and shape of soil structure.
(f) Moist soil consistence.
(g) Abundance and size of rock fragments.
(h) Abundance and size of roots.
(i) Horizon boundary conditions.
(j) Parent materials.
(k) Pores, quantity and size.
(l) Quantity of boulders and tree stumps affecting construction.
(m) Any other characteristics of feature that affects permeability of the soil or treatment of sewage effluent.
(2) The depth to bedrock, if encountered, must be determined by the requirements in § 52.02.
(3) The elevation of standing water evident in any soil pit must be identified.
(4) The soil must not be described when frozen, at improper moisture content, or under poor light conditions.
(H) 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 in the soil. The frequency of 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 Department or local unit of government.
(I) All field soil information gathered must be compared with soil survey information. Any discrepancies shall be identified.
(J) Site and soil information gathered in divisions (B) through (I) of this section must be interpreted for suitability for MSTS siting, design, and construction, with consideration of the following:
(1) Surface features impacts from precipitation, run-on, and interflow or any other item that could have potential to adversely impact the ability of the soil to accept water.
(2) Cultural features, including, but not limited to, setbacks and easements.
(3) Site conditions affecting system layout, distribution system requirements, and constructability.
(4) Layers of coarse soil textures that affect treatment.
(5) Disturbed, compacted, cut-filled, or other unnatural condition, if present.
(6) The uniformity of the soil over the site.
(7) Future surrounding land use changes.
(8) Soil sizing factor or loading rate.
(9) An approximation of the rise in groundwater from system operations as determined by a groundwater mounding assessment. A narrative evaluation of the accuracy of the approximation must be provided. The approximation must be related to the requirements in § 52.16(E)(7).
(K) Systems proposed to be located in flood fringes must determine feasibility of relocating the system outside the floodplain.
(M) The proposed soil treatment and dispersal areas shall be protected from disturbance, compaction, or other damage by use of stakes and silt fence or snow fence.
(N) All information gathered in divisions (B) through (L) of this section must be submitted for review and approved by the Department or local unit of government prior to final design. The submittal must also contain:
(1) A map of the proposed soil dispersal area, drawn to scale, showing:
(a) Features with a setback within 150 feet of the system.
(b) Easements within 50 feet of the system.
(c) Floodplains, wetlands, and surface waters, within 100 feet of the system.
(d) Location and elevation of all soil pits, borings, and hydraulic tests.
(e) Two-foot contour lines.
(2) Dates and weather conditions during the field evaluations.
(3) Elevations of the periodically saturated soil or bedrock.
(4) Proposed depths of the system bottom.
(5) Proposed soil loading rate.
(6) System site boundaries.
(7) Anticipated construction related issues.
(8) The name, address, telephone number, and certified statement of the individual conducting the site evaluation.
(9) A narrative explaining any difficulties encountered during the site evaluation, including, but not limited to, identifying and interpreting soil and landform features and how the difficulties were resolved.
(Ord. 2010-162, passed 5-17-2010)