consulted to analyze soil samples taken at the site, and to
advise on design and construction. The design of earthfill dams
should fulfill the following requirements:
The materials should be stable under all probable
conditions of moisture content.
The foundation material should have enough bearing
capacity to support the loaded dam.
The dam should be resistant to percolation of
d) The embankment slopes should be protected against
erosion due to wave action and surface runoff.
e) The freeboard should suffice to prevent
overtopping of the dam during extreme flood flow, and damage due
to frost penetration.
f) The design of earthfill dams should follow the
criteria for compacted embankments in NAVFAC DM -7 Series on Soil
Rockfill. Use rockfill dams where rock is the only
satisfactory material available. The dam should have a
seepage -retarding membrane, either in or on the upstream
embankment. Design this membrane to remain watertight while
subject to temperature changes and other forces. All other
requirements for earthfill dams are applicable.
Concrete or Masonry. Use a concrete or masonry
gravity dam only where earthfill and rockfill types are not
applicable and where the spillway must be incorporated in a
strong dam structure. The design of these dams should fulfill
the following requirements:
a) The dam must be stable against overturning,
sliding, shear, uplift ice thrust pressure, and earthquake
b) The foundation must have enough bearing capacity
to support the structure with the reservoir full.
The dam and the foundation must be leakproof.