Hydrological Storage Function And Recharge Plan Of A Typical Restored Wetland In Western Jilin Province

The study area is located in the Momoge National Nature Reserve(MNNR),Zhenlai County of Jilin Province,China.As the typical saline wetlands,MNNR is an important food source base of the critically endangered migratory bird Grus leucogeranus,at the same time plays important roles in climate regulation,hydrological regulation,water quality improvement,biodiversity maintenance ect.In recent years,MNNR has suffered from continuous dry years.Meanwhile,the negative effects of water conservancy projects,reclamation corrosion,animal husbandry and oil extraction,have caused the drop of wetland surface water levels drop,shrinkage of wetland area,and decrease of water storage capacity.Therefore,it is urgently needed to restore such hydrologically degraded wetlands.The mechanisms of wetland ecological process is the scientific frontier of wetland restoration and protection research,and has important significance for the restoration of wetland ecosystem function.Momoge wetland faces severe problems such as the degradation of hydrological functions,and it is imperative to study its hydrological storage function,provide concrete hydrological recovery plans,and provide scientific basis for recovery.In this paper,Momoge typical degraded wetland is taken as the research object,based on the stable isotope technique and HYDRUS-1D model to study the moisture transport of degraded wetland hydrological regulation and storage function,and provide scientific reference for the restoration of hydrological function of degraded wetland.The main research results include:The mechanisms of wetland hydrological processes are the scientific frontier of wetland restoration and conservation,which is of great significance to the restoration of wetland ecosystem function.MNNR is facing with serious problems such as hydrological function degradation,and it is urgent to study its hydrological storage function,provide concrete and practical hydrological restoration plan,and provide a scientific basis for restoration engineering.A representative hydrologically degraded wetland was taken as the research object,this study analyzed the soil water transport based on the stable isotope technology and HYDRUS-1D model,through which the scientific reference for accurate wetland water replenishment was proposed.The main research results include:1.Study on the characteristics of soil water migration in degraded wetlands based on stable isotope.In this study,the field sampling and indoor simulation were used to compare the numerical model with soil moisture monitoring data to fit the atmospheric precipitation line,analyze the source of soil water and water,and the average residence time of soil.The following main conclusions were obtained:1.1 Different sources of soil moisture were obtained,and the source of soil moisture at different depths was considered to be different.The surface 0-30 cm was mainly derived from precipitation and was easily affected by evaporation.The middle layer of 30-80 cm was mainly supplied by the upper and lower layers;deep layer 80-100 cm of soil water,even down to 100 cm,mainly comes from groundwater recharge;1.2 The model was used to calculate the average residence time of the soil and obtain the data of the key water restoration time for degraded wetland restoration.The 0-20 cm is about 1.7 months,and the 80-100 cm is about 5.8 months.The data shows that as the depth increases,the vertical migration of soil moisture takes longer and the speed becomes slower.It shows that the recharge of different depths of soil needs a certain amount of time to be realized.With the increase of the depth of replenishment,the time for replenishing the surface of wetland will increase,and the water will have enough time to move to the depth of restoration.2.Simulation and Prediction of Recovered Wetland Soil Water Shift Based on HYDRUS ModelUsing the HYDRUS eco-hydrological model,combined with the meteorological monitoring of field research areas and the determination of soil physical properties of wetlands,the typical wetland vegetation and soil moisture parameters under different developmental stages were determined,and the main factors including meteorology,groundwater,and soil root absorption were taken into account to achieve research.The recovery of the characteristics of soil water resources transported by different vegetations in the wetland was compared with the measured values,and then the data system for forecasting the capacity of the wetland for regulating and storing water resources was corrected and the reasonable ecological water demand and important time for water supply compensation were calculated.The main conclusions are as follows:2.1 The root mean square error(RMSE)of soil moisture in each layer varies from 0.00714 to 0.01964 cm3/cm3,and the correlation coefficient R2 varies from 0.67746 to 0.85709.The results show that after adjusting the model parameters,the actual and simulated values fit well.better.On the whole,soil fits from 0 to 40 cm and 80 to 100 cm are better,while soil from 40 to 80 cm is weakly fitted.2.2 Analysis of the dynamic characteristics of soil moisture in each layer of the experimental area found that the soil moisture content of the wetland began to increase from 0 to 40 cm as the depth of the soil layer deepened,and decreased at a depth of 40 to 80 cm at 80 to 100 cm.The depth increases;however,the change in soil moisture decreases as the depth of the soil increases.The response of the soil moisture in the upper layer to the precipitation is more consistent.In order to ensure the development of typical wetland vegetation types and improve wetland restoration,it is usually from the end of June to the beginning of July that the use of human engineering or natural accumulation of water for ecological restoration of degraded and dehydrated wetlands is an important time to maintain reasonable water requirements for their habitats.node.