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 trap sediment in field runoff. Sediment basins and forest and grassed riparian buffers trap sediment
before it reaches waterways.
placing fertilizer correctly to optimize crop uptake, and timing fertilizer application to meet crop growth
requirements. Sediment-attached nutrients can also be controlled by sediment control BMPs. Nutrients
can also be intercepted or transformed by BMPs such as cover crops, riparian buffers, controlled
the soil profile, thus reducing nutrient losses. Nitrate may be removed in riparian buffers through
denitrification and plant uptake, whereas organic nitrogen and phosphorus, attached to sediment may
be reduced through sediment trapping practices.
Pesticides. Pesticides can be removed by using cover crop management and integrated pest
management techniques of applying pesticides only when needed with the proper type applied, at the
correct rate, and time. The transport of sediment attached pesticides can be slowed by the same type of
BMPs that are used to trap sediment. Pesticides that are adsorbed to soil particles can be trapped in
filter strip and riparian buffers.
4.2.2.2 Best Management Practices
The effect of a Best Management Practice (BMP) on the receiving water body is very site
specific and is influenced by the extent of the problem, meteorology, hydrology, distance to the water
body, treatment and maintenance (NWQEP 1989). In determining management options, consider that
a reduction in erosion rate may or may not result tin improved water quality. Nutrients and chemicals in
solution or attached to fine sediment particles can cause water quality problems independent of the
volume of gross erosion. The amount of applied nutrients that reach a water body may be more of a
function of runoff or fine sediment loss that total soil loss.
Best management practices reported in the literature typically differ by design and specifications
from conservation practice standards in SCS field office technical guides. Research results from the
literature are often edge-of-field studies with highly controlled conditions that may not relate directly to
field conditions particularly due to problems of scale. Factors unrelated to experimental design that
affect treatment strength include information and education, technical assistance, conservation ethic,
economy, and government support. Table 8.3 is a general guide for BMPs discussed in this chapter.
Construction. A RMS for urbanizing land may include BMPs to control erosion on lands
undergoing development for non-agricultural uses such as housing, industrial areas, recreational areas
and roads. BMPs provide for water disposal and the protection of the soil surface. Smolen et al.
(1988) developed a state-of-the-art design manual for planning and implementation of erosion and
4.2-3
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