Study On Soil And Water Loss Based On Landscape Pattern In Southern Mountain Region Of Jinan

Jinan is famous for "spring city" and 72 of them are well-known.The flow of spring lies from extraordinary hydrology and geology structure in Jinan's southern mountain region.However,soil and water loss has been being the primary problem in this region.Along with the frequent break of springs,soil and water conservation becomes emphasis of cco-environment management.The work on soil and water conservation merely concentrated on small watershed formerly.But after a great deal of study,it is found out that there is great correlation between landscape pattern and soil and water loss and landscape pattern is a dominant reason for soil and water loss. Based on Universal Soil Loss Equation (USLE) and supported by Remote Sensing (RS) and Geographic Information System (CIS) ,the study worked out the intensity and distribution of soil and water loss in study area.Then the article analyzed the relationship between landscape pattern and soil and water loss in this region from the view of landscape.The result shows that there is a great deal of irrationality in landscape pattern.Finally, rational disposition measures were put out.The main contents follows:(1 )The study collected all of the informations about precipitation,soil,terrain,vegetation and artifical action and disposed them under the GIS software,then distribution maps of R,K,SL,C,P separately in grids were gained.After overlaying all of these factors together and computing them based on USLE,soil and water loss intensity map was finally worked out.(2) The study area can be separated into ten watersheds.The proportion of each erosion level and erosion modulus in every watersheds can be caculated.Then on the base of spatial distribution of erosion,dominant factors,situation,human activity and spatial difference in terrain,the study area is separated into three parts including Suburb area,Three-valley area and Shahe area.(3) The theory of landscape ecology considers landscape pattern as the main reason for soil and water loss on large scale.By computing landscape indices concerning landscape type,terrain gradient, patch character and comparing them among the three areas,the resultindicates that:In Suburb area,where artifical disturbance is acute,there is the most number of factories and mines and soil and water loss is most serious by the influence of city spreading, so anti-erosion effect of landscape pattern is very bad in this area.With broad valleys between mountains,Shahe area is predominant by agricultural landscape and anti-erosion effect is better than Suburb area.Three-valley area,with higher mountains and steeper slopes,is slightly disturbed by human activity,so there is fine eco-environmention and it has the best effect of anti-erosion. As a result,from Suburb area to Shahe area and then to Three-valley area,the landscape pattern becomes better which leads to lower intensity of soil and water loss.(4)Since irrational landscape pattern is the main factor of soil and water loss,in order to sustain the eco-environment developing in positive direction and to make it compatible with human life and economy development,right measures aiming at different territorial characteristics should be taken.Under the precondition of enhancing vegetation coverage,the main measure is optimizing landscape pattern and improving connectivity between natural landscapes.Then the sources of soil and water loss can be reduced,the pathes of erosion will be cut off and the damage of erosion will decrease gradually.