Geology Reference
In-Depth Information
Table 9.2
Return period daily precipitation amounts (mm) for precipitation intensification and increase in
precipitation. Also shown is average annual precipitation for each scenario.
Climate scenarios
Return period (y)
Base (mm)
5%I (mm)
10%I (mm)
20%I (mm)
5%P (mm)
10%P (mm)
20%P (mm)
2
81
84
86
92
86
90
98
5
103
106
110
117
108
114
123
10
123
127
131
140
129
136
147
20
146
152
155
166
153
161
175
25
156
161
167
179
164
173
187
50
189
195
202
216
199
208
226
100
206
213
220
235
216
225
247
200
222
230
238
255
234
246
266
500
268
278
288
308
282
296
321
Average annual
precipitation (mm)
1028
1006
1012
1029
1081
1129
1229
(http://www.prism.oregonstate.edu/) to adjust for
orographic effects. PRISM is also available on the
Forest Service website (http://forest.moscowfsl.
wsu.edu/fswepp/).
Cligen was used to generate seven climate files
for Fort Scott. The files were the baseline (unad-
justed for climate change or orographic effects -
no orographic adjustments were needed), three
files with rainfall intensification of 5, 10 and
20%, and three files with precipitation increases
of 5, 10 and 20%. The precipitation intensifica-
tion and precipitation increase climate files were
developed using WEPPCAT to adjust Cligen
parameters for climate change.
The potential effect of climate change on pre-
cipitation for various return periods is shown in
Table 9.2. Each of the seven climate files was gen-
erated for a period of 1000 years, so that precipita-
tion, runoff volume, peak runoff rates and
sediment delivery could be estimated for very
long return periods.
water tables in wet seasons because of the clay
subsoil. Slopes are quite moderate, while runoff
may be high because of high precipitation, low
available soil moisture storage, and very low
infiltration and deep percolation rates.
For the cropped area in the Osage river water-
shed, the Parsons soil is a reasonable representa-
tion. Most of the cropped area is underlain by a
clay subsoil. This clay pan drastically reduces
water movement below about 0.5 m, which
causes increased surface runoff for the cropped
areas. Additionally, crop yields can be drastically
reduced by short periods of drought.
While there is considerable cropping in this
area of the Osage river watershed, towards the
east, timber begins to increase and cropland
decreases. A high percentage of the Osage river
watershed is in grass.
The soil characteristics used in these model runs
for the Parson silt loam are shown in Table 9.3.
9.4.4 Management
9.4.3 Soil
The major crops in this region are corn, soy-
beans and wheat. There is also considerable
grassland for beef cattle production. These form
the basis for the modelling of four management
scenarios - corn, soybeans and wheat with
The dominant soil on the area is the Parsons silt
loam, with a surface layer of silt loam and a sub-
soil of clay to silty clay loam. It is moderately
well to poorly drained. There may be perched
