Assessing water renewal of the northern coastal zone in China using a variable fuzzy pattern recognition model

An integrated indexes system for assessing water renewal of the northern coastal zone is developed; and rough sets theory is used to eliminate the redundancy in the indexes system. Then a variable fuzzy pattern recognition model is selected to evaluate the state of water renewal, which involves fuzzy information and interval numbers of classification standard values for evaluation. The indexes system and evaluation model are illustrated in water renewal evaluation of Dalian City. The results of the recent ten years show that natural renewal is much lower than social renewal. The evaluation result of the planning year implies that measures including increasing efficiency of water consumption, increasing use of reclaimed water amounts, desalinated water and seawater, and use of trans-basin water work are effective for improving social renewal; furthermore, water use of trans-basin work is the most sensitive factor influencing social renewal, and other measures including use of reclaimed water, water-saving of urban living, use of seawater for industry, water-saving of agriculture and water-saving of industry are in sequence of sensitivity.