| The Qinling Mountains are the north-south dividing line and central water tower of the People's Republic of China.The analysis of its water resource risk is an important basis and prerequisite for rationally formulating water resources planning,controlling and reducing risks and losses.It is important for protection and restoration of the ecological environment and the maintenance of biodiversity.This study takes the Shaanxi section of the Qinling Mountains as the research area.Under the premise of analyzing its water resources status and main water resources risks,combined with Geographic Information Technology,Set Pair Analysis Theory and Grey System Theory and others,dynamic analysis,simulation and system control of water resources risks in the Shaanxi section of the Qinling Mountains are carried out.The main research contents and results are as follows:(1)The socio-economic profile and water resources conditions of the study area have been sorted out and analyzed,and it is concluded that there are uneven temporal and spatial distribution of water resources,incomplete water-saving mechanism,protection pressure on water environmental,insufficient construction of water conservancy engineering facilities,and soil erosion in the economic and social development of the study area for many years.The water resources risks in the study area are divided into five types: resource-based risks,managementbased risks,engineering-based risks,water-quality risks,and disaster-based risks.With the help of the PSR model,the risk assessment indicators were screened,and a risk identification indicator system consisting of 25 indicators in 5 subsystems was established.Then,the risk level of each index is divided into five levels I,II,III,IV,and V from low to high.The K-means algorithm is used to determine the classification standards for each level.Combined with the theory of set pair analysis,a water resource risk assessment model for the Shaanxi section of the Qinling Mountains was constructed.(2)Based on the water resource risk assessment model,the water resources risk of the Shaanxi section of the Qinling Mountains in 2018 was analyzed on the county scale.From the spatial distribution point of view,resource-based risks and water-quality risks are gradually increasing from south to north;management-based risks show a trend of gradually decreasing from the central area of the Qinling Mountains to the east and west ends;engineering-based risks show a gradual increase from the central urban area to the surrounding counties;disaster-based risks show a trend of decreasing risks from north to south and east to west.In terms of risk types,the engineering-based risk in the study area is the most serious,with high-risk areas accounting for about 63% of the area,mainly in Shangluo City on the southern foot of the Qinling Mountains;resource-based risks and disaster-based risks are in the second place,with high-risk areas account for about 20-40% of the area.Areas with high risk of management-based risk and water-quality risk account for the lowest proportion,with over 70% of counties and districts showing low risk.(3)The three counties of Baqiao,Chang'an,and Zhen'an are selected as the representatives of the three types of high,medium and low risk areas,and their water resources risk evolution laws from 2010 to 2019 are analyzed.As of 2019,the comprehensive water resources risk of Chang'an District has been reduced from level IV to III,and the level of risk connection degree of level IV has dropped by nearly 60%.The comprehensive level of water resources in Baqiao District is always level IV,but the level of risk connection for level IV is reduced from 0.42 to0.28,a decrease of 33%.The connection degree of level II risk in Zhen'an County has changed from 0.38 to 0.42,an increase of 10%,but the risk level is always level II and there is no increase.The three typical districts of Baqiao District,Chang'an District and Zhen'an County are not only facing greater pressure on the amount of water resources,but also have higher risks in water resources management,water disaster prevention and water conservancy project construction,respectively.Their risk levels are in order of level IV,IV,V.(4)Based on the grey prediction theory,a water resource risk prediction model for the Shaanxi section of the Qinling Mountains was constructed,and the water resources risk in typical risk areas from 2020 to 2025 were predicted.The results show that if the current development model is continued,the level IV connection degree of comprehensive water resources risk in Baqiao District will continue to drop to 0.2,a decrease of about 28%;the level III connection degree of comprehensive water resources risk in Chang'an District will drop to 0.34,a decrease rate of 15%.This indicates that the water resources risk in Baqiao District and Chang'an District will decline to varying degrees in the next five years,but the decline is not large,and there is no change in risk level.The comprehensive water resources risk of Zhen'an County will rise to Level III in 2020 and fall back to Level II in 2025,indicating that the risk of water resources in Zhen'an County will fluctuate in the next five years,but under the policy of ensuring the two bottom lines of development and ecology,there is no sign of further deterioration.(5)According to the different types of risk manifestations in Baqiao District,Chang'an District and Zhen'an County,three different risk control plans are set up for simulation control:water control plan,water disaster prevention plan and water conservancy project driving plan.The results show that under the intervention of the water control plan in Baqiao District,the water resources risk has been significantly alleviated,while the water disaster prevention plan and ater conservancy project driving plan are not very effective in the short term.This shows that only long-term persistence to greening,afforestation and comprehensive management of soil erosion can effectively reduce the disaster sensitivity and ecological vulnerability of the Qinling Mountains. |
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