underflow dam unit provides a barricade to pol...
underflow dam unit provides a barricade to pollutants suspended in runoff water
which otherwise finds a way through streets and streams. They use leaning
culverts to allow water which is moving downstream to run off while keeping the
spill well contained. The dam unit includes a dam sandwiched between limiting
side walls above the dam. The baffle’s lower limit extends below the height of
the dam forming a waterway between the baffle and the dam. Floating pollutants
become ensnared against the baffle while hydraulic pressure allows subsurface
stream water to flow the barrier channel and over the dam.
dams carry water discharge over their crests and are made of materials not
easily eroded by the discharges, therefore, allowing water to flow over from
its top and afterward down to its front face. The dam sometimes acts as an
overflow spillway. They consist of a mass so heavy that the reservoir's water
cannot push the dam downstream (thicker at the base than the top). Horizontal
pressure on the dam is exerted as the water becomes deeper. Overflow spillways
are constructed where there is intense pressure as compared to underflow
spillways which cannot withstand massive pressure on the dam tipping it over.
J. D. (1997) Geomorphic Effects of
Overflow Dams. Brookfield, VT: Ashgate
J. (1999) The Free Flow and Submergence
Of Underflow Dams. U.S. Geological Survey