Divisional water quality management-based pollution source control in China's watersheds: an analysis by introducing economic factors.

Abstract

Divisional water quality management (DWQM) is widely adopted in watershed pollution control. During 2011-2015, China zoned 708 priority controlled areas (PCAs) and 774 non-priority controlled areas (NPCAs) for key watersheds. DWQM at watershed level provides guidance on pollution source control (PSC) at local (provincial, city, and county) level. To identify the consistency between DWQM and PSC, a total of 29,688 enterprise-level data from China was analyzed with the difference-in-difference model. The economic factors that affect both are adopted to identify the causes of the disparities between them. The results show that PCAs were more effective than NPCAs and non-controlled areas (NCAs) in reducing COD emissions, thus better achieving divisional water quality goals. NPCAs were no more effective in reducing COD emissions than NCAs. Local government administration and potential subsidies are key to COD emission reductions, but they do not encourage technological progress. Lesser COD emission reductions were achieved in China's national key ecological function zones (NKEFZs) and upstream areas than in other areas. Current DWQM potentiallyaimed at relativelyshort-term economic benefits, which led to inconsistency with PSC particularly in NPCAs. To improve the coordination between them, ecological integrity should be the focus. Market-based watershed funding mechanism, especially watershed ecological compensation, transforms the short-term economic welfare from pollution control into long-term watershed ecological benefits.