Evaluation Of Eco-geological Environmental Carrying Capacity In Mianning County

Mianning County is located on the eastern edge of the Qinghai-Tibet Plateau,which is more fragile due to the complex geological structure,fault development,the fragility of the eco-geological environment background,combined with the influence of social and economic development and human engineering activities.The evaluation of the carrying capacity of eco-geological environment in this area is the key to promote the balanced development of economy,resources and environment,it is also an important basis for protection and ecological construction planning.This paper collects the multi-source data of geology,topography,meteorology,hydrology,social economy and so on,and carries on the eco-geological environment survey to Mianning County,draws lessons from the previous research results and combines the regional characteristics,based on the hierarchical analysis method,establishes the evaluation index system of eco-geological environmental carrying capacity in Mianning County from three aspects: geological environment,ecological environment and social economic environment.The comprehensive evaluation model is used to evaluate the carrying capacity of eco-geological environment in Mianning County,and through the calculation of multi-period data,the dynamic change status of eco-geological carrying capacity is obtained.Finally,according to the analysis results,and the existing eco-geological environment problems in the study area,the countermeasures of geological disaster prevention and eco-geological environment protection are put forward.The results and insights gained through the study are as follows:(1)On the basis of collecting data,constructing index system and calculating comprehensive weight,the carrying capacity index of eco-geological environment is calculated,and the spatial distribution map of carrying capacity is generated.After the field investigation of the eco-geological environment in Mianning Country,the index system for evaluating the carrying capacity of eco-geological environment in Mianning Country was constructed.On the basis of the weight assigned by the analytic hierarchy process and the entropy method,the comprehensive weight of each index is determined.Then the comprehensive evaluation model is used to superimpose the index layer,the carrying capacity index grid map of ecological environment,geological environment,social economic environment and eco-geological environment was obtained according to the calculation.Finally,the natural breakpoint method is used to divide the four grades of excellent good,medium and poor,so that the spatial distribution map of different carrying capacity grades of ecological environment,geological environment,social and economic environment,and eco-geological environment was obtained.(2)Based on the eco-geological environmental carrying capacity index layer of Mianning County in 2018,I have done three horizontal section lines perpendicular to the strata,crossing different terrain units and carrying capacity zoning grades,then I analyzed the change trend of eco-geological environmental carrying capacity index on three sections in the north,middle and south.carrying capacity profiles in the north,middle and south of the study area are a?b?c;at the "a" of Carrying capacity profile,the carrying capacity index is high in the middle and low on the both sides;the index of eco-geological environmental carrying capacity on section “a” and section “b” is high in the east and low in the west;at the "b" of carrying capacity profile,the carrying capacity index is high in the east and middle,and in the eastern edge is low;at the "c" of carrying capacity profile,the carrying capacity in the east is the highest,and the carrying capacity from west to east revealed a fluctuating growth trend.On the whole,the index of eco-geological environmental carrying capacity varies greatly in the east and west of Mianning Country,and the range of variation is obvious.The carrying capacity in the west and north is poor,and the carrying capacity in the southeast is strong.(3)Mianning County eco-geological environmental carrying capacity comprehensive index shows an approximate "U" type of change trend,the index fell sharply between 1990 and 2000,and gradually rose between 2000 and 2018.Overall,the index is on the rise.Based on the grid layer of eco-geological environmental carrying capacity index in Mianning Country in 1990,2000,2010 and 2018,the comprehensive carrying capacity index of four time points is calculated by using the comprehensive index model,which can show the dynamic trend of carrying capacity change in three time periods.Between 1990 and 2000,the comprehensive index of carrying capacity decreased by 8.27%,and the carrying capacity of eco-geological environment decreased;between 2000 and 2018,the carrying capacity continued to rise;the comprehensive index of carrying capacity increased by 4.71% between 2000 and 2010,and the carrying capacity of eco-geological environment increased slowly,the comprehensive index of carrying capacity increased by 10.49% between 2010 and 2018,and the carrying capacity of eco-geological environment showed a high-speed upward trend;between 1990 and 2018,the carrying capacity of eco-geological environment decreased first and then increased,and the comprehensive index of carrying capacity increased by 6.12%,the carrying capacity of eco-geological environment in 2018 has been improved compared with 1990.(4)As the geographical location is different,the dominant factors of eco-geological environmental carrying capacity index change are also different,the higher altitude area is greatly affected by natural factors such as temperature and precipitation,the lower elevation area and the flat terrain area are greatly affected by social and economic factors such as population density and GDP density.Between 1990 and 2018,the areas with excellent eco-geological environmental carrying capacity were mainly distributed in the flat areas of the Anning River Valley and the Yalong River Valley with the elevation of less than 2500 meters;the areas with poor eco-geological environmental carrying capacity were mainly distributed in the high elevation areas of the Xiaoxiangling Mountains,the Yak Mountains and the Jinping Mountains with the elevation of higher than 3000 meters.The spatial distribution pattern of carrying capacity of eco-geological environment is formed under the control of geological environment and influenced by ecological environment and social and economic environment.Because of the small influence of human activities,the northern and southwest of the study area are mainly affected by vegetation coverage,precipitation and temperature.Flat terrain areas such as the Anning River Valley and the Yalong River Valley are obviously affected by population density,GDP density and the proportion of construction land.