Detailed Soil Survey of the Mount Revelstoke Summit Area.

TABLE 9 .GUIDES FOR ASSESSING LIMITATIONS FOR SEPTIC TANK SOIL ABSORPTION FIELDSThis guide applies to soils to be used as an absorption and filtering medium for effluent from septictank systems . A subsurface tile system laid in such a way that effluent from the septic tank isdistributed reasonably uniformly into the natural soil is assumed when applying this guide . A ratingof severe need not mean that a septic system should not be installed in the given soil, but rather maysuggest the difficulty, in terms of installation and maintenance, which can be expected,ItemsAffectingUse None to SlightDegree ofSoil LimitationModerateSeverePermeability Moderately rapid Moderate (approx. 1 - Slow (less than approx .class (approx . 1 - 5"/hr .) . 0.5"/hr .) . 0 .5"/hr .) .Percolation rate About 20 to 45 min ./ 45 to 60 min./inch . Slower than 60 min ./inch .(Auger hole inch .method3)Depth to seasonal More than 72 inchea .5 48 to 72 inches . Less than 48 inches .water table4Flooding hazard Not subject to flooding . Not subject to flooding . Subject to flooding .Slope 0 to 9% (AD) . 9 to 15% (E) . More than 15% (> E) .Depth to bedrock Over 72 inches .6 48 to 72 inches . 6 Less than 48 inches .or other imperviousmaterials .1. The limitation ratings should be related to the permeability of soil layers at and below depth ofthe tile line .2 .3 .4 .5 .Soils having a permeability rate greater than about 5 inches/hour or percolation rate less thanabout 20 min ./inch are likely to present a pollution hazard to adjacent waters . This hazard shouldbe noted but the degree of hazard must, in each case, be assessed by examining the proximity of theproposed installation to water bodies, water table and related features .Refer to Alberta Dept . of Manpower and Labour (1972) or U. S. Dept . of Health, Education and Welfare(1969) for details of this procedure.Seasonal means for more than one month . It may, with caution, be possible to make some adjustmentfor the severity of a water table limitation in those cases where seasonal use of the facility doesnot coincide with the period of high water table .A seasonal water table should be at least 4 feet below the bottom of the trench at all times forsoils having a slight limitation (U .S . Dept . of Health, Education and Welfare, 1969) . The depthsused to water table or bedrock are based on an assumed tile depth of 2 feet . Where relief permits,the effective depth above a water table or rock can be increased by adding appropriate amounts offill .6. Where slope is greater than 9% a depth to bedrock of 48 to 72 inches is a severe limitation .