5. Conclusions
In this study, the alluvial fan is confirmed further to be an important
land resource and still has utilization potential in RRB. The main
conclusions are as follows:
(1) There are 826 alluvial fans with 1166.03 km²in LRB. The quantity of
all alluvial fans is dominated by the ones with area not more than 1
km², but the area of alluvial fans is dominated by the ones with area
more than 10 km2.
(2) The distribution of alluvial fans is uniformed in LRB. The quantity
of alluvial fans is concentratedly distributed in the center and east in
LRB, and the area distribution trend is opposite with quantity.
Especially in Damshung county in the west of LRB, the area of alluvial
fans is 485.20 km2.
(3) Alluvial fans provide materials and places for local human and
livestock to exist and settlement. The area of grassland is the most in
all land-use types. The area ratio of cropland and imperious area in
alluvial fans are just 2.16% and 4.52%, but which in LRB are 18.98%
and 9.18%.
(4) The two types of alluvial fans have the more utilization potential
in the future due to their considerable area and low land-use degree.
The first one is alluvial fans which is occupied by grassland no less
than 50%. And second one is alluvial fans which is occupied by
grassland and bare land not less than 50% and 30%. Meanwhile,
considering the accessibility of alluvial fan, the majority of alluvial
fans are located within 5 km to road, village and river. The quantity
ratio of alluvial fans distance to tertiary road, village and village
within 5km are 93.70%, 53.63% and 61.86% respectively, and area ratio
are 97.50%, 46.14% and 77.38%, respectively. Therefore, alluvial fan
has the utilization potential in LRB where the suitable land for human
is shortage.
Acknowledgments : This research was supported by the Strategic
Priority Research Program of Chinese Academy of Sciences(No.
XDA20040202)and the second Tibetan Plateau Scientific Expedition and
Research Program (STEP) (No. 2019QZKK0603)