Ala. Admin. Code r. 420-3-1-.48
Current through Register Vol. 43, No. 1, October 31, 2024
Section 420-3-1-.48 - Soil Morphology Method(1) A professional soil classifier may evaluate a site using the soil morphology method.(2) A PHESS may evaluate sites for a Conventional OSS. The PHESS shall be currently employed by ADPH1 conduct these evaluations only in counties approved by ADPH for this program, and adhere to the requirements of these rules. This applies to Small-Flow Systems only.(3) The percolation test method may be used in combination with the soil morphology method to aid in evaluating a site.(4) The PHESS or professional soil classifier may determine that a lab analysis is necessary. However, in the case where the results from the soil morphology method conflict with an evaluation by a representative of the LHD or ADPH, the evaluation results of ADPH shall be final.(5) For Small-Flow single-family dwellings, a minimum of two observation pits or two soil borings shall be required for each EDF, and one observation pit and one soil boring shall be performed in the REDF for lots of less than 15,000 sq. ft. See Table 17 for exceptions. The test holes shall be located no closer than 30 feet apart. The pits or borings shall be evenly spaced to represent the EDF area.(6) For Large-Flow systems and establishments, a minimum of two observation pits or two soil borings shall be required for the initial 600 gpd. One observation pit or one soil boring shall be required for each additional 600 gpd of flow or portion thereof thereafter. The pits or borings shall be evenly spaced to represent the EDF area. The method by which each test is located shall be specified.(7) Soil borings shall be dug to a minimum depth of 48 inches to determine the limiting zone depth, unless prevented by bedrock or an additional 6 inches once ASHES is encountered. The soil boring or observation pit shall be deeper than the recommended trench depth by the required MVS. The minimum diameter of the soil boring shall be 2.5 inches.(8) When observation pits are used, they shall be a minimum of 60 inches deep unless prevented by hard bedrock and constructed in such a fashion as to be easily accessible and safe for the evaluator.(a) The vertical section of the observation pit wall shall be picked to a width of at least 12 inches, from the ground surface to the floor of the observation pit, for observations and note-taking.(b) The soil in the picked zone shall be moist so that the proper colors can be observed and noted. If additional moisture is needed, apply water with a spray bottle. All colors recorded shall be from moist and unmixed samples.(9) The upper and lower depths of each discernible horizon shall be recorded in inches from the surface of the ground. Each horizon shall be given a horizon designation as appropriate, Subscripts are helpful when applicable.(10) The color(s) and USDA textural class for each horizon shall be recorded. Any other pertinent information about the soil or the site, including percent slope and landform position shall be reported. From this information, the location, depth, and size of an EDF can be proposed to the LHD.(11) Soil colors shall be determined using a Munsell chart or equivalent and reported for each horizon. Soil colors may occur as:(b) One dominant color with secondary colors (mottles or redoximorphic features).(c) Several colors with approximate equal coverage (mottled). To the extent possible, all colors should be recorded, with the dominant color first.(12) The depth to the ASHES shall be determined by 420-3-1-.42 Soil Restriction Depth and Vertical Separation. EDF bottoms shall have a minimum separation distance above the ASHES or other restrictive layer, or horizon as established in Table 7. If there is uncertainty about whether a feature qualifies as a restrictive layer or horizon, the LHD shall be consulted.(13) Once the upper and lower depths of each layer are determined and colors are noted, the permeability can be assigned for each horizon. Use Table 21 to assign soil permeability classes based on the USDA System.(14) When soil borings are used to evaluate a site, a 2.5-inch minimum diameter hand operated soil bucket auger shall be used. However, a 2-inch minimum diameter soil probe may be used if the sample can be obtained with horizons in their natural condition with appropriate depths and can be left virtually intact for the LHD's inspection. If there is an indication that problems may exist which would not allow for the proper evaluation of the soil using soil borings, then observation pits or other appropriate testing methods may be required. Ala. Admin. Code r. 420-3-1-.48
Filed July 20, 1988. Amended: Filed June 19, 1992. Repealed and New Rule: Filed December 16, 1999; effective January 20, 2000. Repealed and New Rule: October 20, 2005; effective November 24, 2005; operative March 19, 2006.Adopted by Alabama Administrative Monthly Volume XXXV, Issue No. 04, January 31, 2017, eff. 3/5/2017.Adopted by Alabama Administrative Monthly Volume XLI, Issue No. 03, December 30, 2022, eff. 2/13/2023.Previous Rule .72 was renumbered .48 per certification published December 30, 2022; effective February 13, 2023.
Authors: David Gray, Boyd Rogers, Richard Smith
Statutory Authority:Code of Ala. 1975, §§ 22-2-2(4); 22-2-2(6); 22-10-1, et seq.; 22-26-1et seq.