Study On The Degradation Coefficient And Water Environmental Capacity Of Luyang River In Changsha

Water environment capacity is an important indicator of river water environment management,and pollutant degradation coefficient is an important parameter for water environment capacity calculation.Based on the water quality evaluation of the Changsha section of the Liuyang River,the degradation coefficients and water environment capacity of NH3-N,CODMn and TP were studied by field water group tracking and monitoring.The research results can provide a scientific basis for water resources management in Changsha.The main research contents and conclusions are as follows:1)The water quality evaluation results of the Changsha section of the Liuyang River indicate that the avocado and Liuyang estuary sections can reach the water quality class Ⅲand Ⅳ standards during the period of high water and high water,while in the dry season,the water quality of the avocado section is class Ⅳ,and the water quality of the Liuyang estuary section For the Ⅴ class.The Liuyang estuary has the highest level of water pollution.The main pollution factors are NH3-N,CODMn and TP.2)Using the experimental data measured in the field as the basic data,select the linear function,power function,exponential function,logarithmic function and other line types to fit the degradation coefficients of NH3-N,CODMn and TP.An empirical formula for the relationship between flow rates.The results show that the three indicators are best fitted by a linear function.3)Calculate the water environment capacity by using the 90%guaranteed rate,the average monthly average flow rate and the 90%guarantee rate,and the 7-day minimum daily average flow rate as the design flow rate.The result is:90%guarantee rate,the lowest monthly average flow rate,The water environment capacity of the section:NH3-N is 1218.5t/a,CODMn is 28610.8t/a,TP is 72.4t/a;90%guarantee rate for 7 days continuous minimum daily average flow rate section water environment capacity:NH3-N is 529.3 t/a,COD Mn is 12428.4 t/a,and TP is 31.5 t/a.