| Groundwater resources are not only an important source of water supply.but also an important guarantee for supporting social and economic development and maintaining the balance of ecological environment.However,with the rapid development of China's society,people's demand for groundwater resources is increasing and deteriorating,which leads to the increasingly prominent problem of "water shortage due to water quality".According to incomplete statistics,nearly 50%of urban groundwater in China has been polluted,which has affected the safety of human water security.In order to prevent the continuous pollution of groundwater and further deterioration of water environment,scientific and reasonable division of groundwater water source protection areas is an effective method.In view of this,China promulgated "The Technical Specifications For The Division Of Drinking Water Source Protection Areas(HJ/T338-2007)" in 2007,and revised it for the first time in 2018."The Technical Specifications For The Division Of Drinking Water Source Protection Areas(HJ338-2018)" in 2018,which is the most systematic technical guidance for the division of groundwater source protection areas in China.Based on the characteristics of concealed karst water sources,combined with "The Technical Specifications For The Division Of Drinking Water Source Protection Areas(HJ338-201 8)" issued by the ministry of environmental protection and the existing methods for the division of protection areas,this paper proposes the principles and methods for the division of concealed karst water sources protection areas and applies them to the water sources of Jiuxian county.Get the following understanding:(1)According to hydraulic relation between concealed karst and overlying quaternary aquifer,it is divided into three cases,and dividing principle of groundwater protection areas is given in each case.(2)Determine that the shape of the groundwater protection area is approximately oval and the calculation principle and method of the radius in all directions of the protection areas.(3)Four factors is considered to modify the scope of groundwater protection areas,and eight steps to divide the protection areas,then calculate the area of the protection areas.(4)According to the collected data and field investigation,there are 8 centralized exploit Wells in the Jiuxian county water source,and daily exploitation quantity is about 3.1 × 104 m3/d.The groundwater level is 100?120 m;The total hardness and nitrate in the water source exceeded 112.95 mg/L and 31.77 mg/L,respectively,in the category ? water standard;There are two main pollutant emission enterprises.(5)According to the principle and method of the protection division of concealed karst water source areas,the protection division of Jiuxian county water source areas is divided into two parts:land areas and water areas.The revised results show that the land areas of the Primary protection areas of concealed karst aquifer is 1.9G km2,the Quasi-protected areas is 162.56 km2,Primary protection areas of water areas is 0.11 km2,the Secondary protection areas is 0.26 km2.Overlying quaternary pore aquifer,the Primary protection area is 1.65 km2,the Secondary protection areas is 27.36 km2,the water areas is 1.53 km2,and the Quasi-protected areas is 160.49 km2.(6)According to the status quo of water source areas in Jiuxian county and the division results of the protection areas,it is proposed that the protection areas should be managed from three aspects:Water Quantity Protection,Water Quality Protection and Dynamic Monitoring,and the change rules of nitrate and total hardness in water source areas should be strictly monitored. |
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