A Method of catchments health assessment under value-pressure model and its application in urbanized river network area –an example of Shanghai, China?

Key words: 
• catchments health assessment /
• value-pressure model /
• river network area /
• Shanghai

Abstract: Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shanghai was conducted to test the method for catchments health assessment in urbanized river network area. Seven indicators that described four dimensions of river, river networks, land use and functions, local features were used to assess catchments values; while possible change rate of urbanization and industrialization in the next three years were chose for catchments pressure assessment. Aspects related to catchments classification, indicators measurement and protection priority have been considered in the development of the strategies for catchments health management. The results showed that value-pressure assessment was applicable in urbanized catchments health management, particularly when both human and catchments had multiple demands. As a result of over 30 years rapid urbanization, more than 70% of Shanghai river network area was still in a healthy condition with high catchments values, among them, 39% was under high pressure. Poor water quality, simplifying river system and weakening local feature of river pattern had largely affected catchments health in Shanghai. Lack of long-term monitoring data would seriously restrict the development and validity of catchments health assessment.