07-12-1993 Council Packet - Laserfiche WebLink

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Ntemo - 2700 White Oak Circle July 7, 1993 Page 2 All of this was occurring during a transition with the City septic ordinances. In early 1978 the City hired a full time septic system inspector and adopted a new septic system ordinance and design manual. The design manual (Resolution i^^894. Section 2. Item ID) indicated that "for proper functioning of (a trench) system the minimum depth of the ground water or seasonally saturated conditions shall be more than 5*." Section 6 (B-1) indicated that "the bottom of fenches and beds shall be at least 4’ above the water table or bed rock". The procedure for soil borings (Section 3) indicated that "soil borings at least 8' deep (5* below the bottom of proposed drainfield trench) shall be taken to determine soil types and water table information ..." The system installed in 1978 based on information submitted by the builder and accepted bv the Citv, met the code standards for a system built in 1978. • 1979 Code Revision in Januar>' 1979 the soil boring section of the design manual was amended to include :he wording "soil borings shall identify depth at which soil is mottled, indicating the depth of seasonal water table." Funher. the required separation between the bottom of the filter rock and the seasonal high water table was reduced to 3’, :o match the State recommended standards at that time. It was not the intent of the 1979 code changes to require that all existing systems not meeting the 3’ separation be upgraded. Although all new systems were required to meet the 3 separation, no attempt was mad^c to determine whether existing systems met the 3’ separation. • 1992 Code Revision This policy changed in February 1992 when the City adopted the new MPCA Chapter 7080 standards which specifically defined existing systems not meeting the 3 separation, as nonconforming. MPCA took this position on the oasis that effective sewage treatment stops when the effluent reaches a saturated zone, and 3' of unsaturated soil is required ♦or adequate treatment. We adopted those standards because Met Council required it as pan of our sewer plan update, and because DNR required it as pan of the Shoreland Regulations. As Council is aware, staff did not stan doing soil borings to determine conformity ot existing systems until spring of 1993. • Mound not necessarily required Neaton indicates that "Weekman is proposing" installation of a mound system. Weekman is merely advising the property owner that the drainfield repairs likely will involve consintction of a mound, but that the pro|Kny owner must hire a site evaluator to design and construct a system that meets the code requirements. The City does not -propose” specific repairs but