Geology Reference
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Chisel
No Till
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Fig. 9.5 Effect of climate change
on runoff and sediment yield.
Scenarios are intensification of
precipitation of 5%, 10% and 20%
(5%I, 10%I and 20%I) and increases
in precipitation amount of 5%, 10%
and 20% (5%P, 10%P and 20%P) as
computed using WEPPCAT for
Cligen parameters.
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Chisel
No Till
Grass
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5%I
10%I
20%I
5%P
10%P
20%P
average annual sediment yields as shown in Fig.
9.6. Based on these results, while climate change
would increase sediment yields in rare storms, it
would increase average annual sediment yields
by a greater percentage.
The generated climates were used to run WEPP for
1000 years for the small watershed for each of the
four management scenarios. Results are shown in
Figs 9.5 and 9.6.
WEPP was responsive to both intensification
of precipitation and to increases in precipitation
amount. This was reflected in both runoff and
sediment yield for all managements as shown in
Fig. 9.5. While increases in average annual pre-
cipitation were fairly small, the largest being of
the order of a 20% increase in average annual
precipitation, increases in runoff and sediment
yield were much greater, ranging to over a 50%
increase in average annual runoff and sediment
yield.
The effect of precipitation intensification and
precipitation increase due to climate change
seemed to have a smaller effect on sediment
yields for various return periods than its effect on
9.6 Summary
The WEPP model was applied to a small water-
shed about 5 km from the Marmaton river in
southwest Missouri, and about 25 km east of Fort
Scott, KS. The Marmaton River runoff eventu-
ally flows into the Osage river, a major river sys-
tem that contains important reservoirs and
channels for power generation, recreation and
water supply for the state of Missouri. Reducing
sediment yield to the river system from small
upstream watersheds like the one modelled in
 
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