Research On Water Resources Allocation Based On River Ecological Base Flow

With the continuous development and use of water resources in mountainous areas,the ecological environment of some mountainous rivers has been affected and damaged to a certain extent.In order to scientifically coordinate the contradiction between off-channel diversion of water and ecological baseflow in mountainous areas,promote ecological baseflow safeguard measures and optimise regional water resources allocation,this paper takes the Mengboro River as an example and focuses on the baseflow baseline value and regulation value of river ecology,the loss of off-channel water supply for ecological baseflow safeguard diversion The paper also discusses the ecological baseflow of the river and the measures to ensure the economic development of the region.The main research results are as follows:(1)The ecological baseflow baseline and regulation values of each control section of the Mengboro River were analysed,the ecological baseflow guarantee rate and the maximum regulation value under natural conditions and irrigation area influence conditions were studied for each control section respectively,and the water deficit under the ecological baseflow target guarantee value was calculated.The results surface:? The Beimiao,Xiangshan,Kejie,Kas,Wandian and Old Town sections can basically meet the ecological baseflow target regulation value under natural conditions,but under the influence of irrigation district diversions,ecological baseflow shortage occurs at all sections,and the amount of ecological baseflow shortage increases with the decrease of natural incoming water at the sections.?The ecological baseflow guarantee rate tends to increase with the increase of the natural incoming water at the cross-section.The difference between the maximum control value of ecological baseflow that can be met at each section before and after the diversion of water from the irrigation district project is large,and the ecological flow of the river is significantly affected by the diversion of water from outside the river.?The analysis of the multi-year average ecological baseflow shortage at each section shows that the water shortage during the dry season is serious and requires priority protection.(2)Based on the calculation of the reduction of off-channel diversions,the loss of offchannel water supply and the increment of ecological value after securing ecological baseflow were calculated respectively,and the effect of securing ecological baseflow in the river was analysed.The results show that.? Reducing the amount of water diverted out of the river will lead to economic losses in urban life,rural life,industrial production and agricultural production,with the average multi-year loss range for each area being:Bei Miao 11.35-2.193 million yuan,Xiangshan 28.35-77.7 million yuan,Kejie 12.3-23.75 million yuan,Kas 19.0631.34 million yuan,Wandian 16.9-25.88 million yuan,Old Town 713-18.6 million yuan.The amount of water supply loss increases as the ecological baseflow regulation value of the river increases.?By reducing the amount of water diverted from the river and implementing ecological baseflow protection measures,the ecological baseflow protection rate of the river has been significantly increased and the ecological baseflow protection effect is remarkable.?As the ecological baseflow control value increases,the ecological value increases.The ecological value range for each section with different ecological baseflow control values is:North Temple 0.007-0.008 billion yuan,Xiangshan 3.484-3.602 billion yuan,Kejie 4.5804.696 billion yuan,Kas 292.9-3.049 billion yuan,Wandian 3.698-3.817 billion yuan,Old City 543.6-599.9 million.?As the ecological baseflow control value increases,the economic benefit decreases and the ecological benefit increases,and the ecological benefit is negatively correlated with the economic benefit.To ensure that the social and ecological benefits brought by ecological baseflow in a river are greater than its loss in a certain range,the ecological baseflow control value can be set according to the ecological health of the river or the expected value of ecological baseflow,combined with the affordable economic loss.(3)According to the conclusion of the ecological base-flow benefit analysis,water resources allocation in the irrigation area is carried out according to the benefit relationship equation,and measures for regional economic development and ecological protection are proposed.The results show that.? Ecological baseflow control values for each control section at maximum effectiveness:Bei Miao 0.4 m3/s,Xiangshan 3.0 m3/s,Kejie 9.0 m3/s,Kas 11.5 m3/s,Wandian 14.5 m3/s,Old Town 35.0 m3/s.?In areas where water resources are scarce,as the ecological baseflow increases,the water shortage in various sectors of the region intensifies,the increase in ecological benefits is lower than the decrease in water supply benefits,and the comprehensive benefits of the region decrease;in areas where water resources are abundant,as the ecological baseflow increases,the comprehensive benefits of the region show an increase and then decrease,and the inflection point of the ecological baseflow?benefit relationship curve is the maximum comprehensive benefits of the region??In view of the serious leakage of the water supply network in the Mengbolo River basin,the low reuse rate of industrial water,the low utilization coefficient of agricultural irrigation water and the weak water conservancy infrastructure in the fields,water saving measures for domestic use,industrial use,agricultural use and water reuse were proposed,and water saving potential was calculated for the above measures,with a total water saving of up to 133 million m3.?The following measures are proposed to ensure the sustainable development of ecological baseflow and the regional economy:improving the efficiency of the water supply network and the penetration rate of water-saving appliances,promoting the implementation of a stepped water price system,intensifying efforts to promote water conservation,improving the reuse rate of industrial water,optimising the regional industrial structure,reducing the amount of water used for 10,000 yuan of added value,improving the impermeability of canals,improving field irrigation infrastructure,popularising efficient irrigation water-saving techniques,and water dispatching measures.