Simulation And Regulation Of Water Allocation For "Production-living-ecological" In The Yellow River Delta Based On System Dynamics Model

The allocation of production water,domestic water,and ecological water(“production-living-ecological”)is a water distribution plan that aims to maximize comprehensive benefits and coordinate production,domestic water,and ecological water.The Yellow River Delta has the most typical estuarine wetland ecosystem in the mid latitude region of China.It is not only a natural species gene pool,but also a barometer of ecological health in the Yellow River basin.The reasonable allocation of water use is great significance for regional economic and social development and wetland health.Based on this,firstly,this paper takes Yellow River Delta as the research area,combines Landsat data,NOAA meteorological data,Dongying statistical yearbook data and uses the quota method to calculate the production water demand and domestic water demand of Yellow River Delta.According to the characteristics of ecological water demand in Yellow River Delta and the availability of data,the calculation of ecological water demand is divided into two parts:inside and outside the Yellow River Delta Nature Reserve.The calculation of ecological water demand outside the nature reserve adopts the water balance method and quota method;The ecological water demand in the reserve is calculated by combining the SEBS model and water balance method.Based on the results,suggestions on ecological restoration and water supplement scheme for Yellow River Delta Nature Reserve are proposed.Secondly,based on the system dynamics model,this paper simulates the water allocation of“production-living-ecological”in Yellow River Delta by comprehensively considering the population,economy,ecology and other impact factors.On the basis of sensitivity analysis,three configuration scenarios are set for configuration,namely:(1)the baseline scenario is set according to the actual situation of the study area in the past decade and the expected future development trend;(2)The ecological priority scenario aims to complete a certain area of wetland ecological restoration every year,with the goal of completing 1 million mu of wetland ecological restoration by 2030,and ensuring that domestic water consumption is not affected;(3)The water-saving scenario is set to increase the water-saving irrigation area,improve the reuse rate of reclaimed water,and other water-saving measures.The research results indicate that:(1)In terms of time scale,the daily average evapotranspiration of Yellow River Delta Nature Reserve will gradually increase from January to July in 2020,and reach the annual high value from June to August.From July to December,it gradually decreases and exhibits a single peak throughout the year.The highest evapotranspiration occurred in July,reaching 9.35mm/day,while the lowest evapotranspiration occurred in December,with a value of 0.62mm/day.On a spatial scale,the distribution characteristics of daily average evapotranspiration in each month of the year are relatively consistent.The daily evapotranspiration of the eastern and southern parts of the northern Yellow River Delta Nature Reserve is higher than that of the northern coast,and the daily evapotranspiration of the central and western parts of the southern nature reserve is higher than that of the eastern part.From January to February,the overall daily average evapotranspiration in the research area was very low,with high values concentrated in the cultivated land area west of the southern protected area;From April to October,as the temperature rises,the vegetation in the Yellow River Delta Nature Reserve comes to the growing season,and the daily evapotranspiration increases significantly,reaching the peak in July.Among them,the reed marsh,reed meadow and tamarix shrub areas in the middle of the southern reserve become high value gathering areas;From October to December,the daily evapotranspiration in the study area showed an overall downward trend as the temperature decreased,reaching its lowest value in December.(2)According to the calculation of Yellow River Delta’s“production-living-ecological”water demand,in 2020,the Yellow River Delta’s production water demand will be 8.39×10~8m~3,with a domestic water demand of 0.93×10~8m~3,ecological water demand is 3.51×10~8m~3.In 2020,the ecological water demand outside the Yellow River Delta Nature Reserve will be0.5×10~8m~3,of which the ecological water demand of rivers and lakes is 0.3×10~8m~3,with a water demand of 0.2×10~8m~3for urban greening.The total ecological water demand in Yellow River Delta Nature Reserve is 23.04×10~8m~3,with a vegetation water requirement of 5.86×10~8m~3;The ecological water demand in non vegetation areas of wetlands is 9.91×10~8m~3;Wetland soil water requirement is 5.83×10~8m~3;The minimum ecological water requirement for biological habitats is 1.17×10~8m~3;The minimum water requirement for preventing coastal erosion is 0.27×10~8m~3.(3)Under the benchmark scenario,the water supply and demand ratio continues to shrink from 2020 to 2030,with production water consumption in 2030 being approximately four times the sum of domestic water consumption and ecological water consumption.Under the ecological priority scenario,the average annual increase in ecological water consumption is0.31×10~8m~3,approximately 52.1%of production water cannot be met annually,and the water supply to demand ratio will reach 0.69:1 by 2030,resulting in a serious shortage of water supply capacity.In the water-saving scenario,the water supply system can provide approximately 3.6×10~8m~3more than the baseline scenario of water,but it still cannot fill the water demand gap for ecological construction.On the basis of the implementation of water-saving policies,it is still necessary to increase the water diversion of the Yellow River Delta and other inter basin water transfers in order to achieve the coordinated and high-quality development of water use in the Yellow River Delta.