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SANITARY FACILITIES Endnote -- SANITARY FACILITIES PAGE 2 DF 3 OB/8/00 This report shows the degree and kind of soil limitations that affect septic tank absorption fields, sewage lagoons, and sanitary landfills. The limitations are considered "Slight" if soil properties and site features generally are favorable for the indicated use and limitations are minor and easily overcome; "Moderate" if soi! properties or site features are not favorable for the indicated use and special planning, design, or maintenance is needed to overcome or minimize the limitations; and "Severe" if soil properties or site features are so unfavorable or so difficult to overcome that special design, significant increases in construction costs, and possibly increased maintenance are required. This report also shows the suitability of the soils for use as daily cover for lardfills. A rating of "Good" indicates that soil properties and site features are favorable for the use and good performance and low mai ntenante can be expected; "Fair" iMicates that soil properties and site features are moderately favorable for [he use and one or more soil properties or site features make the soil less desirable than the soils rated "Good"; and "Poor" iMitates that one or more soil properties or site features are unfavorable for the use and overcoming the unfavorable properties requires special design, extra maintenance, or costly alteration. SEPTIC TANK ABSORPTION FIELDS are areas in which effluent from a septic tank is distributed into the soil through subsurface tiles or perforated pipe. Only that part of the soil between depths of 24 to 72 inches is evaluated. The ratings are base on soil properties, site features, and observed performance of the soils. Permeability, a high water table, depth to bedrock ar to a cemented pan, and flooding affect absorption of the effluent. Large stones and betlrock or a cemented pan interfere with installation. Unsatisfactory performance of septic tank absorption fields, including excessively slow absorption of effluent, surfacing of effluent, and hillside seepage, can affect public health. Groundwater can be polluted if highly permeable sand and gravel or fractured bedrock is less than 4 feet below the base of the absorption field, If slope is excessive, or if the water table is near the surface. There must be unsaturated soil material beneath the absorption field to filter the effluent effectively. Many local ordinances require the[ this material be of a certain thickness. SENAGE LAGOONS are shallow ponds constructed to hold sewage while aerobic hatter is decompose the solid erd liquid wastes. Lagoons should have a nearly level floor surrounded by cut slopes or embankments of compacted soil. Lagoons generally are designed to hold the sewage within a depth of 2 to 5 feet. Nearly impervious soil material for the lagoon floor and sides is required to minimize seepage and contamina[i on of groutd water. TAis report gives ratings for ' [he natural soil that makes up the lagoon floor. The surface layer and, generally, 1 or 2 feet of soil material below the surface layer are excavated to provide material for the enbanknK•nts. The ratings are based on coil properties, site features, and observed performance of the soils. Considered in the ratings are slope, permeability, a high water cable, depth to bedrock or [o a cemented pan, flooding, large stones, and content of organic natter, Excessive seepage due to rapid permeability of the soil or a water table that is high enough to raise the level of sewage in the lagoon causes a lagoon to function unsatisfactorily. Pollution results if seepage is excessive or if floodwater overtops the lagoon. A high content of organic matter is detrimental to proper functioning of the lagoon because it inhibits aerobic activity. Slope, bedrock, and cemented pans can cause construction problems, and large stones can hinder compaction of the lagoon floor. SANITARY LANDFILLS are areas where solid waste is disposed of by burying it in soil. There are two types of landfill, trench and area. In a trench landfill, the waste is placed in a trench. It is spread, compacted, and covered daily wi [h a thin layer of soil extavat ed at the site. In an area landfill, the waste is placed in successive layers on the surface of [he soil. The waste is spread, compacted, and covered tlaily with a thin layer of soil form a source away from the site. Both types of landfill oust be able to bear heavy vehicular traffic. Both types involve a risk of grourdwa[er pollution. Ease of excavation and reveget ation need to be considered, The ratings in this report are based