Discussion on the Construction of Ecological Water Network in Guangxi Province of China

The water network plays an important role in maintaining the stability of regional water resource and ecological environment. It is also affecting the harmonious development between environment and economy. Guangxi is one of the provinces with relatively rich water resources in China, while the ecological water network exists deficiencies and faces challenges. The current situation and defects of ecological water network in Guangxi province will be discussed. By studying the experience of the establishing and the preserve of ecological water network in various regions at home and abroad, some suggestions and targeted measures will be mentioned for a better ecological water network in Guangxi.

Spatial and seasonal variations of hydrological responses to climate and land-use changes in a highly urbanized basin of Southeastern China

Climate and land-use changes are two major factors that significantly affect the watershed hydrology cycle. It is essential for regional water resource management to quantitatively assess the respective hydrological impact of these two factors. In this study, the Soil and Water Assessment Tool (SWAT) was constructed to quantify the contributions of climate and land-use changes to runoff at the annual and seasonal time scales in the Qinhuai River basin (QRB), where significant urbanization occurred from 1986 to 2015. Moreover, based on the partial least squares regression, the specific impact of individual land-use change on major hydrological components was evaluated at the sub-basin scale. The results showed that: (1) the predominant patterns of land-use change in the QRB included the transformations from paddy fields to urban areas and dry lands, forest to dry lands and dry lands to urban areas; (2) the flood seasonal precipitation series and all air temperature series had significant increasing trends over 1986–2015, and annual and seasonal runoff series had significant increasing trends and had an abrupt change point in 2001; (3) the average annual, flood seasonal, and non-flood seasonal runoff increased 238.5, 130.2 and 108.3 mm, of which land-use change was responsible for 77.6, 55.1, and 104.8% of the increases, respectively, while climate change was responsible for 22.4, 44.9, and −4.8%, respectively and (4) the hydrological response to land-use change showed an obvious decrease in actual evapotranspiration (ET) and significant increases in surface runoff and baseflow. The decrease of ET and increase of baseflow could be attributed to the conversion patterns from paddy fields and forest to dry lands, while the conversions from paddy fields and dry lands to urban areas caused a remarkable increase in surface runoff in the QRB. The study demonstrated that these practicable approaches were beneficial for the more unbiased views of the hydrological responses to climate change and land-use change in the highly urbanized basin, which were also critical for the sustainable development of regional water resource and future land-use planning.

Evaluating the dynamic resilience process of a regional water resource system through the nexus approach and resilience routing analysis

<p>The increasing magnitude and frequency of undesirable events, driven by climate and anthropogenic changes, have given rise to various approaches for quantifying the resilience of regional water resource systems. However, the deficiencies of these approaches in describing linkages among subsystems and disturbance-dependent resilience have hindered the assessment and prediction of resilience in water resource management. The nexus approach enables the propagation of a disturbance to be simulated (a process called surrogate disturbance generation). An approach analogous to a unit hydrograph is developed, and resilience routing (strain flow routing), which is a novel framework and model of the dynamic resilience process, is proposed for the evaluation of a regional water resource system. The proposed framework and model are applied to the Jinghong regional water resource system. Taking a pollution event as a disturbance, the responses of the water supply, fishery and electricity subsystems are simulated to test the validity of the proposed methods. The linkages among subsystems are determined according to the sink-source dynamic using the nexus approach, and the levels of surrogate disturbance transformed from the disturbance event can be quantified by the processes of dynamic resilience evaluation. The shape of the dynamic resilience process is quantified by the parameters of unit resilience routing with disturbance independence and reflects the characteristics of the system responding to the disturbance. The proposed method helps to assess the adaptive capacity of a water system to alleviate and regulate disturbances. Furthermore, after the calibration and validation of the assumptions of linearity inherent in the method, it can also be used to predict the dynamic resilience processes of every subsystem in response to any disturbance event affecting a regional water resource system.</p>