Research progress on hydrology and water resources in the Nenjiang River Basin under the changing environment of the Northeast Geography Institute

The hydrological response under the changing environment and its impact on water resources security are global issues of general international concern, and are also major strategic issues facing China's sustainable development. The Nenjiang River Basin is an important energy base, main grain production area and wetland concentrated distribution area in China, and has made significant contributions to China's economic and social development, food security and ecological security.

In the past 50 years, global climate change and high-intensity human activities have profoundly changed the hydrological cycle process and its regularity of the Nenjiang River Basin, exacerbated the shortage of water resources and spatiotemporal variability, and successively brought about tributary river channel outages, frequent flood and drought disasters, and wetlands. A series of outstanding water and ecological environment problems such as degradation and secondary soil salinization have become the bottleneck restricting the sustainable economic and social development of the basin. Coupled with the current large-scale water diversion project of the Grain Yield Development Project, new and higher demand for water resources, as well as the uncertainty of the impact of future climate change on water resources, will surely bring serious problems to regional water security, food security and wetland ecological security. Challenge.

The Hydrology and Water Resources Discipline Group of the Northeastern Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences addressed Mann-Kendall test, Morlet wavelet analysis, Petttt test and rainfall-runoff accumulation in response to the hydrological and water resources response and its associated ecological and environmental problems in the Nenjiang River Basin under changing environment. Curves and other methods have been used to analyze the temporal and spatial changes of temperature, precipitation, evapotranspiration, and runoff in the Nenjiang River Basin over the past 50 years, with a focus on the analysis of runoff response to climate change. The main results of the study show that in the past 50 years, the temperature in the Nenjiang River Basin has shown a significant increase in overall trend. The overall spatial distribution of precipitation has shown a decrease in the right bank and an increase in the left bank. Hydrological elements also show different changes.

Affected by climate change and human activities, the overall runoff of the Nenjiang River Basin showed a downward trend. Based on the catastrophe point test of 1974, the runoff changes of the entire Nenjiang River Basin were divided into a base period (1956-1974) and a period of human activity (1975-2009). Within the entire Nenjiang River Basin, the contribution rate of climate change to runoff change was identified as 69.6% -80.3%, and the contribution rates of human activities on the upper, middle and lower reaches to runoff change were 19.7%, 27.3% and 30.4%, respectively. Precipitation, land use change and water conservancy project construction are the main driving factors affecting runoff changes. The research results will provide scientific basis and decision support for water resources utilization planning and management in Nenjiang River Basin, wetland restoration and protection, and sustainable development of irrigated agriculture.

Related research was jointly funded by the National Key Basic Research Development Program (973) (2010CB428404) and the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2YW-Q06-2, KZCX2-YW-126). The research results were published in academic journals such as Hydrology and Earth System Sciences, Water Resources Management, and Advances in Water Science.