The basic demand of the monitoring and sampling was that the contamination was distributed uniformly,while the contamination was distributed uniformly or not was affected by the circumstance hydrology characteristic,the draining manners,and the background concentration of the river,etc. For meeting the demands of the monitoring and sampling, the plane planar water quality model was applied into the reverse deduction and the optimization of the draining manner. The results showed that the tri-limber hole draining manners is the optimal.
