SOIL EROSION & SEDIMENTATION
An estimated 25,000 tons of soil erode within the Higginsville City Lake Watershed on an
average annual basis. This amounts to approximately 7.5 tons per acre per year of soil erosion
from all sources. Approximately 55 percent of all sediment produced in the watershed is derived
from sheet and rill erosion on cropland, 20 percent from permanent gullies, 15 percent from
cropland ephemeral gullies, and 10 percent from stream bank, road ditch, and flood plain scour
erosion. Approximately 8,000 tons of sediment are delivered to the Higginsvflle City Lake on an
average annual basis. This results in a one percent loss of the lake's storage capacity every
three years.
Grade stability problems were observed in the watershed. Instability in the form of bank
erosion and channel bottom degradation is present in some stream channels, gully systems, and
road ditches. Installation of new culverts along some roads appears to have triggered
instability in associated channels. Channel work just above Higginsville City Lake at Highway
AA seems to have initiated stream bottom degradation. Many road culverts within the watershed
are deteriorating, as evidenced by erosion around wing-walls, sagging and broken aprons, and
weathered concrete. Undersized and plugged culverts also cause stability concerns. Washing-out
of culverts could initiate degradation of stream channels, stream bank erosion, and movement of
stored sediment.
Shoreline erosion around the lake is not a significant source of sediment. In general, it is
not a problem but isolated areas should be treated. Treatment solutions will vary depending on
the location and severity of the problem.
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