Comprehensive Evaluation Method of Surface Water Quality in Arid Region

With the building of the South-to-North Water Diversion Project, surface water resources in arid regions has been recharged effectively. Generally speaking, the surface water-supply resources in arid region include two parts, local water and secondary water, which makes its water quality evaluation has its own particularity and different from regular evaluation. So the surface water quality evaluation in arid region is unique.For it involves a wide range of complex factors in practice, the fuzzy set theory and fuzzy matter-element theory were applied to the study. The mathematical model was established based on the quantity demand of both local water and secondary water, and meanwhile taking the subjective and objective conditions into account carefully, so the weights of the two parts were obtained respectively. The results proved to be a good solution to solve the problem of water quality evaluation level in arid areas,and the research achievements also openup new ideas for comprehensive evaluation method of surface water quality in cities of arid region.