Water fluxes of Nenjiang River Basin with ecological network analysis: Conflict and coordination between agricultural development and wetland restoration

Abstract

With population growth and the rapid development of society and the economy, the excessive exploitation of water resources has not only aggravated the mismatch between water supply and water demand, but also caused the deterioration of ecological water environments, particularly wetland systems. Previous research efforts have analyzed the contradictions between supply and demand in the Nenjiang River Basin, but the water resource system needs further research to identify the relationship between the internal nodes and the changes of the wetland hydrological relationship. It is necessary to establish a systematic network model to evaluate the structure and functional attributes of water resources at the basin scale, and to balance water resource utilization and wetland protection. We established an ecological network representing the water resource system in the Nenjiang River Basin, studied the changes in the system-level network configurations from 2007 to 2015, and analyzed multiple scenarios. This method also reflects the impact of human activities on wetland hydrology and water resources. The results show that the structural efficiency of the water network in the Nenjiang River Basin has been declining, redundancy has increased, and the contradiction between water supply and water demand has become increasingly serious. Agricultural recession flow is the main consumer of water resources; furthermore, the wetland has high control intensity over the system. A water conservancy project changed the eco-hydrological relationship between wetlands and other hydrological units, which led to the degradation of the ecosystem and also affected the robustness of the system. Agricultural return water is an important water supplement source for wetlands, but the duration and amount of the supplement cannot reliably meet the wetlands’ ecological needs. Finally, based on the research findings, the construction of the National Wetland Park is facilitating wetland conservation. Overall, the model results provide a scientific basis for water resource and wetland ecological restoration, so as to strengthen the sustainable management of resources.