A Surface Water Quality Assessment Method Based on Combination Weight

A new water quality assessment method is presented based on combination weight. Firstly, the subjective and objective weights of the evaluation indicators are calculated by following methods: AHP (Analytic Hierarchy Process) method, dynamic entropy method and the weighting method based on the proportion of the pollutants over water quality standard level. These weight vectors are integrated based on TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method to gain the combination weights of evaluation indicators. Then some typical water quality indicators are taken as evidences and an new evidence combination rule is introduced to combine these evidences on the basis of weights of the evaluation indicators. Finally the water quality class with the highest belief is regarded as the evaluation class. Actual application of the presented method is carried out and the assessment class accords to surface water status, which shows that this method is objective and effective. Using this method, the variation trend of water quality can also be analyzed by the belief fluctuations of water quality classes.