不同估算方法与监测频率对氮磷负荷估算的影响OACHSSCD

To determine the appropriate monitoring frequency and estimation method,improve the accuracy of estimating the flux of river pollutants,and reduce the error of flux estimation,based on the daily flow and total nitrogen and total phosphorus concentrations of the Fifth drainage Ditch in the Ningxia Yellow River Diversion Irrigation District from 2022 to 2023,eight estimation methods were adopted,setting three times a week,once a week,once every two weeks,and once every three weeks.The annual fluxes of total nitrogen and total phosphorus in the fifth drainage ditch were estimated at five sampling frequencies once every four weeks.The results showed that using a sampling frequency of once every three weeks and the LOADEST method to estimate the TN flux in the fifth drainage ditch can yielded relatively reliable estimation results.The method of the flow-weighted average concentration was the best way to estimate the TP flux in the fifth drainage ditch.Sampling once every two weeks was the most suitable frequency for TP estimation.It was necessary to estimate the TN and TP of the fifth drainage ditch during the irrigation period by using high-frequency monitoring frequencies.A sampling frequency of three times a week was the optimal sampling frequency.The linear interpolation method was the best method for estimating TN during the irrigation period,and the concentration curve method was the best method for estimating TP.