Nitrogen Random Simulation In Roundwater Resources

As an important source of water supply, groundwater is used in industry, agriculture and municipal field in a growing proportion, and has become the main water source in many urban regions. The excessive exploitation of groundwater, however, has triggered a series of geological issues, such as the formation of underground funnel, and groundwater pollution, etc, among which the "three nitrogen pollution" is ackonwdedged as one of the most outstanding issues of groundwater pollution and has aroused widespread concern, especially researchers’Shen Yang City exploits the underwater of Banghe River as the main water supply of the entire city and that of Hunhe River as the main supply of research region, both of which are directly involved in the groundwater circulation. Regrettedly, the "three nitrogen pollution" within the research region is more than severe, and has posed a great threat to the strategic reserve of water resources. Based on the permeability coefficient K and randomness of precipitation infiltration recharge, a parameter stochastic model is established, which can reflect the water permeability coefficient and the randomness of precipitaion’s effect on the simulation result. In contrast with the deterministic model, the solution procedure of stochastic model is more scientific and reasonable due to research on numerical simulation of abundant groundwater. Remarkably, it can provide necessary information and evidence for groandwater extraction decision-making and analysis of "three nitrogen pollution" risk.This study employed a comprehensive groundwater simultaion software GMS, established the stochastic model of groundwater flow with MODFLOW module, and stochastic model of "three nitrogen" movement. It also, after analyzing the hydrogeological conditions, generalizing the aquifer geological conditions, computedequilibrium items, and typing model parameters, established the conceptual model of groundwater flow. According to previous deterministic model after identification verification of senior sister graduate, this study analyzed resonable partition of permeability coefficient in the deterministic model and partition of rainfal intensity. On the basis of all this work, it randomly simulated the parameters with the use of Latin Hypercube Sampling (LHS), completed the stochastic model of groundwater flow, and calculated the mean, maximum, minimum, and standard deviation distribution of groundwater level with software and statistical tools. The simulation results show that the distribution of water-level mean can replace groundwater flow distribution calculated by deterministic model. The standard deviation distribution illustrates that the water level is less deviated in research region. If we suppose the groundwater is as deep as35m, then we can get the reliability analysis of groundwater exploitation amount which provides information for groundwater exploitation decision-making.On the basis of stachastic model of groundwater flow, this thesis established random model of "three nitrogen" movement, and forcasted the distribution of "three nitrogen" after10years. The simulaed movement of "three nitrogen" suggests the following:the distribution mean of "three nitrogen" concentration shadows the "three nitrogen" concentration distribution calculated by deterministic model; under the condition of non-mean steady flow, the "three nitrogen" is distributed along the Hunhe River and Xihe River in strips, and the pollution of the north bank of Hunhe River is more severe than that of the south bank; the standard deviation of "three nitrogen" concentration in the research region is within1and the cnocentration is on the general less deviated; risk analysis of "three nitrogen" pollution can provide necessary guide for the remediation of groundwater contamination.