There are a lot of vast and narrow plain in the Qin-Ba mountain area of South Shaanxi Province

which is regarded as the essential things. For a long time

local people have worked hard to build their farm land by reconstructing the bank and have acquired great achievements. However much plain can not still get rid of flood rushing calamity

and some have been rushed and repaired once and again; others have been submerged under the mud and sand. Slope and steep land of the mountains is increasing decreased and the soil fertility drops year by year

during tens of years

the average farmland per people of South Shaanxi Province has dropped from more than 0.2 hm2 to 0.067 hm2

what is more

it has dropped to little than 670 m2 in some counties. To protect the basic agriculture land

prolong the usable life of plains in the river

and keep a sustained development

based on a great number of investigation

this article investigated and analyzed the reason of the producing calamity

and then put forward a very good suggestion about repair plains in the river.