Chapter 10: Appendix
188
velocities of released
Ground water recharge may affect aquifer quality
depending on the quality of the recharging water. If the stored water contains
only sediment and chemical
low water
the ground water quality
should not be affected.
Grassed Waterway (412): A natural or constructed channel that is shaped or
graded to required dimensions and established in suitable vegetation for the
stable conveyance of runoff
This practice may reduce the erosion in a concentrated flow area, such as in a
gully or in ephemeral gullies. This may result in the reduction of sediment and
substances delivered to receiving waters. Vegetation may act as a filter in remov-
ing some of the sediment delivered to the waterway, although this is not the pri-
mary function of a grassed waterway.
Any chemicals applied to the waterway in the course of treatment of the adjacent
may wash directly into the surface waters in the case where there is a
runoff event shortly after spraying.
When used as a stable outlet for another practice, waterways may increase the
likelihood of dissolved and suspended pollutants being transported to surface
waters when these pollutants are delivered to the waterway.
Grasses and Legumes in Rotation (411): Establishing grasses and legumes or a
mixture of them and maintaining the stand for a definite number of years as part
of a conservation cropping system.
Reduced runoff and increased vegetation may Lower erosion rates and subse-
quent yields of sediment and sediment-attached substances. Less applied nitro-
gen may be required to grow crops because grasses and Legumes will
organic nitrogen. During the period of the rotation when the grasses and le-
gumes are
they will take up more phosphorus. Less pesticides may simi-
larly be required with this practice. Downstream water temperatures may be
lower depending on the season when this practice is applied. There will be a
greater opportunity for animal waste management on grasslands because ma-
nures and other wastes may be applied for a longer part of the crop year:
Grazing Land Mechanical Treatment (548): Renovating, contour furrowing,
pitting, or chiseling native grazing land by mechanical means.
Heavy Use Area Protection (561): Protecting heavily used areas by establishing
vegetative cover, by surfacing with suitable materials, or by installing needed
structures.
Protection may result in a general improvement of surface water quality through
the reduction of erosion and the resulting sedimentation. Some increase in ero-
sion may occur during and immediately after construction until the disturbed
areas are fully stabilized.
Some increase in chemicals in surface water may occur due to the introduction of
fertilizers for vegetated areas and oils and chemicals associated with paved areas.
Fertilizers and pesticides used during operation and maintenance may be a source
of water pollution.
Chapter 1 O-1 88:
Previous Page
