Diversion Dikes
Diversion dikes should be built at the upslope perimeter of the construction
site to channel rain water away from the disturbed area. The diversion dikes
should be built prior to any earth moving, and should be seeded and mulched
immediately after they are built.
Vegetative Buffer Strips
Of primary importance when construction sites are adjacent to water bodies, a
buffer strip of undisturbed vegetation between the water body and the
construction area reduces run-off water velocity and traps sediment. This
reduces sediment delivery to surface waters and adjacent properties.
Seeding and Mulching
Mulch should be applied to exposed soil at the end of each work day. Seed should
be applied to topsoil stockpiles and bare soil after use of soil and
disturbances to the soil have stopped.
Silt Fencing
Sediment fencing is temporary filter-cloth fencing that is used to catch
sediment-laden run-off from small areas of soil disturbance. This usually
reduces run-off velocity to a degree favorable for sediment deposition.
Vegetative Cover
Natural vegetation controls erosion in several ways. It protects the soil
surface from the impact of falling rain and decreases the velocity of run-off.
It helps maintain the soil's capacity to absorb water and holds soil particles
in place. A construction planner can significantly reduce soil erosion and
sedimentation by limiting the removal of vegetation. If removal is necessary, it
should be done in stages to decrease the duration of soil exposure. Vegetation
should be retained in areas of moderate to high soil erosion potential, such as
steep slopes, drainage ways, highly erodible soils, and stream banks.
Sediment Basin
A sediment basin is a temporary dam constructed across a drainage way to
intercept and retain sediment and other waterborne debris. It provides a
temporary means of detaining sediment-laden run-off long enough for the majority
of sediment to settle out. Special consideration needs to be given on depth of
water table when this practice is used in order to ensure that infiltration of
pollutants do not contaminate ground water aquifers.
Sediment Trap
A sediment trap is a small temporary ponding area formed by constructing an
earthen embankment to intercept sediment-laden run-off from a small disturbed
area long enough to trap and retain it to settle out. This practice should be
installed at points of discharge from disturbed areas for a maximum period of 18
months. Special consideration needs to be given on depth of water table when
this practice is used in order to ensure that infiltration of pollutants do not
contaminate groundwater aquifers.
