Best Management Practices
Best management practices (BMPs) are effective practices that act to reduce
the nonpoint pollution load in water systems and decrease the velocity
of runoff after storm events. These practices are usually created and maintained
for long-term use and coincide with the local water quality standards for
a particular area. Selection and suitability of a BMP should be based on:
site specific conditions, type of land use activity, the physical makeup
of the watershed, and consideration of the pollutant(s) involved.
||Conservation Tillage and No-Till
Conservation tillage is an agricultural BMP that provides long-term
crop residues and vegetation on croplands. This practice greatly reduces
erosion and surface runoff of heavy metals and pesticides, which may reside
in higher concentrations in the surrounding soil. No-plow is a similar
practice that minimizes the spring influx of sediment into nearby waters
by anchoring the soil to the plant root systems. Either way, by retaining
crop residue and vegetative cover, this practice reduces time and energy
on the farmer, it delays the warming and drying of the soil, and overall
maintains a higher quality of soil.
||Contour strip cropping
Various rowcrops and hay in alternating strips planted side-by-side can reduce soil loss
of about 50% compared to the same rotation contoured on its own. This practice
is effective in that it provides rotated crops in different parts of the
soil which act to strengthen the soil characteristics over time by not
continually depleting the resource based on a monoculture. This process
also decreases erosion and runoff and increases the stability of the local
Simple practices can be implemented to offset livestock impacts on
nearby streams and rivers. By providing an alternative water source, for
example, livestock would not be forced to wade in the streams and therefore
would not be as likely to contribute to excess nutrient input from wastes.
Large concentrations of wastes can speed up eutrophication of a stream,
which will eventually decrease the effectiveness of the watershed's sustainability.
Another effect of livestock in waterways is the increased potential for
erosion by streambank deterioration from trampling and compaction. An alternative
to better manage for the watershed could include creating a bridge to connect
pastures where the animals can easily cross the stream without directly
interacting with the water system.
Urban and Suburban
Filter strips are wide areas of vegetation that act to intercept runoff.
They can consist of any type of dense vegetation from woodlands to grass
and can remove various pollutants, such as heavy metals, sediment loads,
and excess organic materials.
Swales are shallow channel depressions where runoff flows. These swales
slow the flow of the runoff water and allow particulates to settle out
and water to infiltrate into the soil. These swales can effectively remove small amounts of excess nutrients and heavy metals.
Constructed wetlands are often used in mitigation of other areas that
lost wetlands due to development. Both natural and constructed wetland
areas are saturated for sufficient time periods and are able to support
unique vegetation adapted for life in such conditions. Wetlands are extremely
efficient in filtering sediment, nutrients, and some heavy metals from
storm water runoff and overflow of nearby water systems.
Structures are often built in residential areas to alleviate stormwater
runoff and retain or detain precipitation from storm events. Detention
ponds are basins that temporarily store runoff from a site and release
it at a controlled rate to minimize downstream flooding. These ponds are
quite effective for pollutant removal, especially suspended sediments,
if well designed.
These trenches are shallow, usually three to eight feet deep, and backfilled
with gravel to create underground reservoirs. Runoff, therefore, is diverted
to the trenches and percolates into the subsoil. Such a practice effectively removes sediments and similar particles from stormwater runoff. This practice is commonly used in both commercial and residential areas.
Construction sites, while under development, can implement many BMPs
to reduce runoff, decrease pollutant loads to nearby water systems, and
decrease the amount of soil washed from the site. Simple practices, such
as setting up straw bales, silt fences, or even filter fabrics can act
to slow runoff and retain sediment during storm events. Other practices,
such as sediment basins to detain runoff or stabilizing entrances of construction,
further decrease sediment and pollutant runoff.
Citizens, commercial businesses, and even local and state agencies can
implement and maintain efficient BMPs by taking the conservative approach
to many everyday landscaping events. For example, sufficiently seeding
grass to promote long-term stabilization of soil surfaces and planting
wildflower cover (a practice used by many highway departments to provide
aesthetically pleasing vegetation along roadways) greatly reduces the potential
for erosion by securing the surfaces with plant roots. Other practices
such as sodding and mulching can also be applied and have similar effective
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