18 Alaska Admin. Code § 72.265

Current through September 25, 2024

Section 18 AAC 72.265 - Soils analysis and report

The soils analysis and report must meet the following criteria:

(1) the number of test holes, minimum test hole depth, and percolation tests must be sufficient to adequately evaluate subsurface characteristics of the area for the type of system proposed;

(2) soils in the usable wastewater disposal area must be shown by percolation test to have an acceptable percolation rate for the type of system proposed; percolation tests must be

(A) performed by a registered engineer, or a person under the responsible charge of a registered engineer;

(B) be performed in accordance with standard sanitary engineering principles and practices;

(C) taken in each soil stratum to be included in an infiltrative surface area; and

(D) confirmed to be accurate by a correlation of the observed soil texture in the test hole with the range of soil texture types associated with percolation rates in 18 AAC 72.530(f)(3);

(3) soil borings and soil analysis must show the location and elevation of seasonal high water table and impermeable strata in relation to the wastewater system;

(4) seasonal high water table must be determined by

(A) monitoring test holes or soil borings taken between June 1 and September 30;

(B) soil mottling analysis;

(C) interpretation of levels of standing open water;

(D) the knowledge and experience of the engineer, based on past subsurface investigative work in the vicinity of the project; or

(E) a combination of these methods;

(5) the depth to seeps, if any, must be recorded; the department may require subsequent monitoring;

(6) in areas known or suspected to contain permafrost,

(A) a soil moisture content profile analysis derived from laboratory testing methods must show the soils are adequately drained throughout the usable wastewater disposal area; and

(B) the results of a geotechnical study must show that the area can successfully be used for the system proposed and will remain stable under the proposed design; and

(7) the report must be sealed by a registered engineer.

18 AAC 72.265

Eff. 4/1/99, Register 149; am 5/12/2016, Register 218, July 2016; am 10/1/2023, Register 247, October 2023

Authority:AS 44.46.020

AS 46.03.010

AS 46.03.020

AS 46.03.050

AS 46.03.100

AS 46.03.110