Chapter 10: Appendix 197
Surface Drainage Field Ditch (607):
A graded ditch for collecting excess water
in a field.
From erosive fields, this practice
increase the yields of sediment and sedi-
ment-attached substances to downstream water courses because of an increase in
the location of the ditches may cause a reduction in sheet
erosion and ephemeral gully erosion. Drainage of high salinity areas
may raise salinity levels temporarily in receiving waters. Areas of soils
that are drained by the ditches
rus Loads, resulting from this practice may increase
not be sig-
or increased although the
nificant. Upland wildlife habitat
areas may be decreased.
habitat formed by
Surface Drainage, Main or Lateral (608):
An open drainage ditch constructed
to a designed size and grade.
Terrace (600): An earthen embankment, a channel, or combination ridge and
channel constructed across the slope.
This practice reduces the slope length and the amount of
pass& over the area downslope from an individual terrace. This
erosion rate and production of sediment within the terrace interval. Terraces trap
sediment and reduce the sediment and associated pollutant content in the runoff
water which enhance
water quality. Terraces may intercept and conduct
to stable outlets, thus, reducing the occur-
rence of ephemeral and classic gullies and the resulting sediment. Increases in
infiltration can cause a greater amount of soluble nutrients and pesticides to be
leached into the soil. Underground outlets may collect highly soluble nutrient
and pesticide leachates and convey runoff and conveying it directly to an outlet,
terraces may increase the delivery of pollutants to surface waters. Terraces in-
crease the opportunity to leach salts below the root zone in the soil. Terraces
may have a detrimental
on water quality if they
delivery of dissolved or suspended nutrient, salt, and pesticide pollutants to sur-
face or ground waters.
Tree Planting (612): To set tree seedlings or cutting in the soil
Trough or Tank (614): A trough or rank,
needed devices for water control
and waste water disposal, installed to provide drinking water for livestock.
By the installation of a trough or tank, livestock may be better distributed over
the pasture, grazing can be better controlled, and
runoff reduced, thus
reducing erosion. By itself this practice
have only a minor
however when coupled with other conservation practices, the
effects of the combined practices may be large. Each site and application should
be evaluated on their own merits.
Use Exclusion (472): Excluding livestock from an area not intended for grazing
Livestock exclusion may improve water quality by preventing livestock from be-
ing in the water or walking down the banks, and by preventing manure deposi-
tion in the stream. The amount of sediment and manure may be reduced in the
water. This practice prevents compaction of the soil by livestock and
Chapter 1 O-197: 9197