Row

Factor

High sediments

1

Surface geology

・ sea Shale

・ gypsum and site content marls

・ the layers of stiff rocks and Shale

・ sandstones

2

Soils

・ fine texture and highly dispersed, sore alkaline, high ability to expansion and compaction

・ granular silt and fine gravel

・ gravel

・ gravel texture-Lummi made of Granite

3

Weather

・ raining for some days with short cycles of thunder

・ frequent heavy thunders

・ dry climate with heavy rain

・ runoff of snow melting

4

Runoff

・ high rate of discharge in surface

・ high amount of water flow in surface

・ hydrologic soils of group D

・ hydrologic soils of group C

5

The unpaved areas

・ deep slope areas more than 30%

・ high altitude, ups and downs

・ slope beds

・ flood resisting ups and downs

6

Limited plant coverage

Lots of sediments

・ land coverage less than 20%

・ dispersed plant coverage

・ the lack of pebble on the ground

7

Land usage

・ more than 50% planted

・ the whole ground is like dispersed pasture

・ the plants recently burned

・ the recently cut jungle coverage

・ lots of road shears

8

High lands erosion

・ erosion plough, gally and a mass in more than 50% of the lands

・ high amount of erosion

9

River erosion and sediment transportation

・ frequent erosion at the river side

・ the erosion at the head and the decrease of their height