Figure 1-7. Section of trench showing layers of compacted refuse.
(3) There are many factors to consider before selecting a site for a landfill
such as available land area, soil conditions, topography, and geologic and
hydrogeologic conditions. Applicable Federal, State, or local regulations must be
reviewed and close liaison maintained with these regulatory authorities regarding landfill
site selection. A few general guidelines are presented below.
(a) Whenever possible, soft (but not sand, silt, sandy loam, or limestone)
soil should be used for landfills because it is easy to excavate and cave-in when rodents
dig to get the garbage. However, consideration must also be given to the water table
(i.e., how deep it is) and what type of soil is present between it and the landfill. An
impervious layer of soil, such as clay, is required to prevent leaching. Therefore, the
soil should be easy to excavate, yet impenetrable towards the bottom so as not to
contaminate the water table. All landfills must be lined to ensure protection of the water