Prediction And Early Warning Of Cyanobacteria Bloom In Changxinggang River

In recent years,with the rapid development of the economy,the impact of humans on rivers and lakes has gradually become prominent,and the degree of eutrophication in water bodies has intensified.Some rivers and lakes have experienced large-scale outbreaks of blue-green algae blooms,seriously damaging the ecological environment of river and lake water bodies,threatening drinking water safety,and endangering human health.Blue algae bloom is a natural phenomenon that is influenced by multiple factors and cannot be solved in a short period of time.Therefore,building a blue algae bloom prediction and warning system can predict the outbreak of blue algae bloom within a certain range.This not only provides theoretical basis for rapid decisionmaking and emergency measures by government departments,improves government response and governance capabilities,but also provides new ideas for research related to blue algae bloom prediction and warning,To provide scientific reference value for better responding to outbreaks of blue-green algae blooms,thereby reducing the ecological hazards and health risks of blue-green algae blooms,and ensuring the health of the ecological environment of rivers and lakes.Therefore,the study selected Changxinggang River,a river in Changxing County,Zhejiang Province,to conduct a study on the prediction and warning of blue-green algae blooms.The sensitive factors for blue-green algae blooms in Changxinggang River were determined,and a probability prediction model for blue-green algae blooms in Changxinggang River was constructed.This is of great significance for ensuring the health of the water ecological environment in Changxinggang River and promoting the process of blue-green algae blooms control in Changxinggang River,and provides a certain scientific basis for relevant departments.The main work carried out and conclusions obtained in this study are as follows:(1)Selecting the sensitive factors of blue-green algae blooms in Changxinggang River:The study used principal component analysis and correlation analysis to comprehensively determine the sensitive factors of blue-green algae blooms in Changxinggang River as ammonia nitrogen,total nitrogen,CODMn,BOD,rainfall,flow rate,and water temperature.(2)Determine the prediction indicators and methods for blue-green algae blooms in Changxinggang River:Based on the situation and completeness of data in Changxinggang River,the study first determined the "probability of blue-green algae blooms occurrence" as the prediction indicator for blue-green algae blooms in Changxinggang River.Due to the need for model construction,based on the advantages and disadvantages of various methods,the characteristics of Changxinggang River,the completeness of data,and the degree of compatibility with the research,a time series and Logistic regression were determined to jointly construct a probability prediction model for blue-green algae blooms in Changxinggang River.(3)Build a probability model for the outbreak of blue-green algae blooms in Changxinggang River:The probability model for blue-green algae blooms in Changxinggang River is divided into probability calculation module and prediction module.The probability calculation module is constructed using Logistic regression,while the prediction module is constructed using time series methods.The accuracy of the probability model for blue-green algae bloom outbreak established by the research institute is 88.89%,and the predicted P-values are all less than 0.181,indicating certain feasibility.(4)Classification and early warning of blue-green algae bloom outbreaks in Changxinggang River:The study referred to relevant standards and specifications,and the probability of blue-green algae bloom outbreaks in Changxinggang River was classified into levels I-V from low to high;In addition,a set of blue-green algae bloom warning workflow has been established for Changxinggang River,which divides the warning level of blue-green algae bloom outbreak probability from light to heavy into three levels of warning,two levels of warning,and one level of warning.Treatment measures have been proposed,including organizing water shoreline inspections,conducting oxygen aeration,and increasing water displacement flow;Finally,the study predicted the probability warning level of blue-green algae bloom outbreaks in Changxinggang River.From April 2023 to October 2023,the warning level for bluegreen algae bloom outbreaks in Changxinggang River was Level 1,Level 2 in November,and Level 3 in December.