区域水资源资产负债表——北仑区水资源存量及变动表案例研究

Natural capital accounting (NCA) plays an important role in the establishment of the institutional system of ecological civilization. Water resource accounting is a key component of NCA, which will lay a solid foundation for sound water management and water efficiency improvement by comprehensively accounting the variation of water withdraw-consumption and identifying key factors to affect the flow and stocks of water metabolism in a local area. At present, the tailored method for water resource accounting at regional scale is still at an early stage. This study, based on the Guideline of natural capital accounting (on trial), aims to uncover the variation of water flows and stocks of the Beilun District, Ningbo City from 2013 to 2016, by employing methods including remote sensing, geographic information system, literature review, on-site investigation, and expertise consulting. It analyzes 15 indicators, including water inflow, outflow, and stocks, etc. A regional water balance model is proposed to quantitatively uncover the characteristics of water consumption and water efficiency in the Beilun District from three aspects, water withdraw, water use, and wastewater discharge respectively. The water efficiencies, in the name of freshwater consumption per unit of GDP and per unit of industrial added value (IAV) respectively,are benchmarked with other areas. The key findings are as follows. The Beilun District has been mainly outsourcing water supply from water plants and ground water outside,and water supply increased from 153. 248 million m³ in 2013 to 183. 615 million m³ in 2016, with an increase rate of 19. 8%. The total water consumption almost kept stable, which was 289. 650 million m³ in 2013 and 293. 030 million m³ in 2016, but the tertiary industry accounted for the most rapid increase of water use with an increase rate of 36. 4%. The freshwater consumption per unit of GDP and per unit of IAV decreased from 4 100 and 3 800 m³/million RMB in 2013 to 3 300 and 3 500 m³/million RMB in 2016, respectively. Wastewater generation and discharge increased from 128. 724 million m³ and 100. 248 million m³ in 2013 to 168. 930 million m³ and 136. 946 million m³ in 2016, with an increase rate of 31. 2% and 36. 6%, respectively. At last, this paper put forward following recommendations on improving the method of regional water resource accounting, such as clarifying the system boundary and definition of some indicators in the water resource balance sheet, reinforcing water use monitoring and high-resolution data collection, and making the logic relationship among some metrics more reasonably.