Preliminary study on assessment of urban river ecosystem health

Healthy river ecosystem is acknowledged as the object of river management,thus the study on urban river issues in terms of river ecosystem health theory is of great significance in theory and practice.Based on the analysis of urban river ecosystem health concept and its connotation,the index system,including water quality,water quantity,aquatic life,p hysical form and riparian wne,together with the five-grade assessment standard described as "very healthy,healthy,sub-healthy,unhealthy,sick",are established.The integrative fuzzy hierarchical assessment model is put forward to carry out the assessment.Furthermore,the above theory and method are applied to the case study of 4 urban rivers in Ningbo city to reveal their health grades and disadvantages,and provide decision-making base for their protection,maintenance and restoration.