| Environmental capacity of the water basin is often used as the basis of total amount control of pollutants, which was concerned by environmental workers for a long time. However, people often used to focus on point source pollution, and have neglected the non-point source pollution impacts to the drainage area. Through water quality monitoring and evaluation, using of export coefficient method to estimate drainage area's pollution load, the main non-point source pollution of Dadu River of Luding Segment was studied. And then establish a model of water environmental capacity to measurement and finally classifies the distribution of the remaining water environmental capacity. The results are as follows:(1) Basin water quality is at good quality, except TN at some section in some period, the remaining guide lines for monitoring water quality are up to III standards. The main pollution factors are TN,TP and COD.(2) Research Valley's COD, ammonia nitrogen, TN, TP load pollution mainly comes from non-point source pollution. Non-point source pollution generated COD, ammonia nitrogen, TN, TP, respectively, each accounting for the total pollution load generated 91.81%, 99.85%, 99.1%, 100%,and the amount of pollution load into the river while accounting for their pollution loads into the river the amount of 97.12%, 99.76%, 99.89% and 100%. Common life pollution is the major source of COD, NH3+-N and TP load, and agricultural chemical fertilizer is the major source of TN pollution load.(3) Non-point source pollution into the river pollution load distribution during the year as the volume of the wet period for the largest and the smallest dry season. 6～10 months of non-point sources of COD, ammonia nitrogen, TN,TP amount of pollution load into the river throughout the year accounted for non-point source pollutants into the river separated by 54.66%, 44.52%, 73.26%, 50.28%.(4) The Water environmental capacity study shows that the basin COD, ammonia nitrogen, TN, TP of the water environmental capacity and remaining capacity at a greater capacity, but uneven distribution of the year. COD and ammonia nitrogen on the maximum capacity of the environment in the 6,7,9 on the COD and ammonia nitrogen during the water environmental capacity of 27643t and 164t, respectively, each accounting for the capacity of the water environment throughout the year about 54.27% and 54.64%. TN and TP on the maximum capacity of the environment in the 6 to 8 months, the capacity of TN and TP of the water environmental are 2933t and 723t, respectively, each accounting for the capacity of the water environment throughout the year about 50.82% and 48.39%.(5) Assigned to the lifestyle of the various sources of pollution remaining capacity of the water environment is, separately, COD3053t/a, N 11.31t/ a, TN320t/a, and TP89.33t/a, and for industrial pollution is, separately, COD46417t/a, N 172.14t/a, TN4871t/a, and TP1360t/a. The distribution of COD and ammonia nitrogen sort by volume is that: urban living> Rural Living> Animal Husbandry> agricultural fertilizer. The distribution of TN sort by volume is that: agricultural fertilizer> Animal Husbandry> urban> rural life. The distribution of TP sort by volume is the order of rural life> towns> agricultural fertilizer> livestock and poultry. |
