11-21-1977 Planning Packet - Laserfiche WebLink

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the fact that al to properly reaches ilts in fFe pres- lal inputs of ■acing of the louse. This cre- pose a health height of a iinepin County ^■e coloration ^ investigation Jld include a v'ith this back- development area Jiying soils ganic soils is e unsuitable olor on the either at or several months T^tion system ided separation ‘■atertables. 'w the surface i of any soil t blue color atertable in y betAx'een 1 and installation 3ttiing occuTs properly. ily have a mottling in- UTiended separ- table cannot system is not If the h then a :?rlay offers sonal \vater- installation lere is : coupled with 't, f y ••■■1 b : V .f IE. «K I w ^ the presence of the most premeable portions of this soil nearer tne surface, means that a shallow trench system will probably function better than the standard system on this soil. Lerdal soils, colored light red on the soils overlay, coimiionly have a seasonal watertable at a depth of 3 to 5 feet. In addition, percolati rates on these soils are often in excess of 60 minutes per inch. For this reason an innovative mound system will function more effectively i either a standard system or a shallow subsurface system. Erin soils indicated by the medium red color on the soils overlay have a high clay content in the subsoil. Tliis often results in percolation rates in excess of 60 minutes per inch. For this reason it is recommended that an innovative mound system be installed on these soils. These systems cannot be installed on slopes greater than 6 percent. 'Hus may represent a serious problem for the site plan as presently diafted. At thTies it is suggested that the watertable in areas of propsed waste treatment systems be lowered tiirough use of agricultural drainage tile to provide the proper separation distance between seepage trenches and a water table. Use of agricultural drainage tile for this pui*}iose is relatively difficult for several reasons: i) the tile :r-.talled must be properly placed to in sure that the watertable is sufficiently lowered not to interfer with the system; ii) the tile lines must be properly maintained by some party, this includes the policing of the tile lines to insure that they are not dis turbed in any manner by the homeowners or utility companies, ^ presence of these tile lines offer a convenient outlet for anyone in the future who has problems with their waste treatment system. M additional word of caution on using this type of arrangement, is that little research has been conducted on the functioning of these systems and there is some question as to how well they will operate. The area indicated as Borrow pit presents another problem for the location of an on-site waste treatment system. Tliese systems are designed on the basis of natural soil characteristics. Tliis means that these systems should not be constructed on filled areas. Tliere are primarily ^vo rea.^ns for this. First, it is difficult to deteimiine the penneability of the fill^ area, which makes sizing the system very difiicult. Second, if che f^ll set es, the distribution lines of the system iv'ill no longer be on grade which result in unequal distribution of the effluent, localized over-loading of the system and eventual failure of the syscem through lack of sufficient tieat- ment and surfacing of tlie effluent. For areas that have been graded it may be possible to have a soil absorp tion system installed if the minimum recommended distance can be mauiUrined between the seepage trenches and the watertable; and if the pcnncabili > (percolation rate) is rapid enough. Tlie chance of f,iiluie for tie s>stem is greatly increased however, since the more penmcaDle portions ot the soil have usually been removed by the grading; the separation dist^ce has been reduced nnd the likelihood of soil compaction during giading is hig • TO:FRilM: DATE: SbTJECT: Calvary Men prosierty wh area. Although th we generail so that pax regulations