30 Sep 01
depending on site-specific conditions (e.g., time, budget, topography, etc.). The topographic mapping
should be referenced to the horizontal and vertical control used to perform the survey and should be
accurate to within 30.0 mm (0.1 ft) in the vertical and horizontal directions. Elevations of
piezometers, monitoring wells, or other instrumentation should be accurate to 3.0 mm (0.01 ft) to
allow for accurate interpretation of data. All surface features such as buildings, utilities, ponds, fences,
trees, streams, ditches, and exploratory borings and trenches should be shown on the mapping.
(5) Horizontal and Vertical Control. At a minimum, three permanent control monuments need
to be established. The monuments should be strategically located so that they are not damaged during
construction and will not be affected by settlement of the landfill. All monuments should be assigned
state plane coordinates. The vertical datum should be mean sea level.
(6) Monitoring Baseline Data. To monitor design concerns, it is often necessary to collect an
initial set of data to establish a baseline for instrumentation such as settlement gauges, monitoring wells,
piezometers, and slope movement markers.
(7) Utilities. All on-site above- and below-ground utilities need to be located. A utility search
should consist of an on-site inspection, review of as-built drawings, and contacts with utility companies.
The project drawings should show the location of on-site utilities, including horizontal and vertical
alignment, type, and size.
(8) Boundary Survey and Property Search. The boundaries for all properties or parcels within
project construction and access limits should be surveyed. The boundary survey should be tied to the
site's horizontal control. A property search should also be conducted to identify property owners of all
affected and adjacent parcels of land. Prior to any investigation or construction activity, it is essential to
obtain construction easements and project rights-of-way. This may take 12 to 18 months; therefore,
coordination with real estate elements should begin as soon as possible.
c. Geological Investigations. After the existing database has been reviewed, geological investi-
gations can then be scoped. The following items need to be investigated in order to design a cover
(1) Landfill Limits. It is imperative that the depth of the waste materials and the limits of the
landfill or contaminated area be determined. Depending on the composition of the waste material, the
limits of the landfill can be tentatively defined by geophysical methods, such as electromagnetic
conductivity surveys and ground penetrating radar. Surface depressions and stressed vegetation along
with historical aerial photographs can also help in delineating approximate landfill boundaries. Intrusive
methods, such as test pits or borings, should be used to verify landfill boundaries. All test pits and
borings should be logged by a qualified geologist or geotechnical engineer. Surveys should also be
made to determine the exact location of any geotechnical investigations used to define the landfill