Water resource security is an important condition for socio-economic development. Recently, the process of urbanization brings increasing pressures on water resources. Thus, a good understanding of harmonious development of urbanization and water resource security (WRS) systems is necessary. This paper examined the coordination state between urbanization and WRS and its obstacle factors in Beijing city, utilizing the improved coupling coordination degree (ICCD) model, obstacle degree model, and indicator data from 2008 to 2017. Results indicated that: (1) The coupling coordination degree between WRS and urbanization displayed an overall upward tendency during the 2008–2017 period; the coupling coordination state has changed from an imbalanced state into a good coordination state, experiencing from a high-speed development stage (2008–2010), through a steady growth stage (2010–2014), towards a low-speed growth (2014–2017). (2) In urbanization system, both the social and spatial urbanizations have the greatest obstruction to the development of urbanization-WRS system. The subsystems of pressure and state are the domain obstacle subsystems in WRS system. These results can provide important support for urban planning and water resource protection in the future, and hold great significance for urban sustainable development.

With the rapid expansion of the Chinese economy in recent years, the urbanization process of the provinces in the Yellow River Basin (YRB) has put serious pressure on the sustainability of the water resources carrying capacity (WRCC). It is necessary to analyze and diagnose the coordination state between urbanization and the WRCC. In this study, based on the Population-Economic-Social-Spatial (PESS) framework and Pressure-State-Response (PSR) model, we developed two index systems for the urbanization and WRCC, respectively. At the basis of the two index systems, the coupling coordination degree (CCD) of the two systems is calculated by applying the improved CCD model. Based on the calculated CCD for each province, the spatio-temporal analysis was performed to analyze the characteristics of CCD in the YRB. The obstacle factor model is utilized to obtain the main obstacle factors. The results show that: (1) the coordination state between the urbanization and WRCC systems was improved to some extent in 2017, compared to 2008, but there are differences in the coordination state of the different provinces in the YRB. (2) In terms of the level of urbanization, the gap between the seven provinces’ performance levels widened because urbanization grew at different rates. The WRCC system’s performance presented a fluctuating downward trend from 2008 to 2017 in the YRB. (3) The pressure subsystem had a significant impact on the two systems’ coordination state in the YRB, while the social urbanization and response subsystem had a less significant impact on the urbanization system and the WRCC system, respectively. Due to the growth of urbanization, the imbalanced development of the WRCC and urbanization has become the principal contradiction that must be solved in order to achieve sustainability in the YRB. The analysis of the coupling relationship between urbanization and WRCC may guide the policy makers in planning for realistic goals. The results provide a guide for high-quality development in the YRB.

As a primary pioneering region in China’s ongoing urbanization process, the Yangtze River Economic Belt’s (YREB’s) urbanization process is itself continually accelerating, causing increasing pressure on the area’s water ecosystem. It is necessary to examine the coordination relationship between the urbanization system and the water ecosystem in the YREB for realizing sustainable urban development. To this purpose, we use two comprehensive index systems, along with an improved coupling coordination degree (CCD) model. This method is used to analyze the coordination between urbanization and the water ecosystem across spatial gradients and temporal scales in the YREB, from 2008 to 2017. The factors acting as obstacles were diagnosed by utilizing the obstacle degree model. The results show that: (1) the coordination state of each region gradually improved during the 2008–2017 period. In terms of spatial distribution, the coordination state between two systems gradually increased from east to west. Moreover, the spatial differences across the 11 analyzed regions gradually narrowed with the passage of time. (2) The coordination between the two systems, from 2008 to 2017, evolved from a state of serious imbalance to a state of good coordination. The two systems passed from an initial period of imbalance or antagonism, coupled with rapid growth (2008–2011), through a period of basic coordination with steady growth (2011–2014), and finally toward a period of good coordination with slow growth (2014–2017). (3) Spatial urbanization and pressures on subsystems are the key factors acting as obstacles in the urbanization system and water ecosystem, respectively. Facing the process of rapid urbanization in China, the coupling analysis of the coordination between urbanization and the water ecosystem can help the government to formulate a reasonable new-type urban development strategy. This strategy will play an important role in China’s sustainable urban development and water environmental protection. The findings of this study provide important support for urban planning in the future.

The urban water ecosystem is a core foundation for the urban construction of ecological civilization. Ecosystem health is directly related to the economic development of the region and the quality of urban residents’ lives. Evaluating the health state of an urban water ecosystem is an important prerequisite for the construction of an ecologically civilized city. This study used Zhengzhou City in China as research area. Firstly, a Pressure‐State‐Response (PSR) model was used to construct an urban water ecosystem evaluation index system. Secondly, after analyzing the deficiency of traditional fuzzy matter‐element extension model in urban water ecosystem health assessment, an improved fuzzy matter‐element extension assessment model (FMEAM) was constructed by introducing the variable weight theory. Finally, using the proposed model above and the data from 2007 to 2016, this study evaluated the water ecosystem health status of Zhengzhou based on water ecosystem health integrated index (WHI). The results showed that the state of the urban water ecosystem in Zhengzhou generally improved during the study period. However, the overall level still remained low and retained an unhealthy state throughout the timeframe. The pressure on the Zhengzhou water ecosystem mainly originates from the increasing urbanization rate, the increased consumption of ecological environmental resources, and household water. Corresponding countermeasures in Zhengzhou have achieved certain results, and the health of the state’s subsystem and response subsystem has improved. However, it remains necessary to further strengthen the protection of the ecological environment, particularly with respect to water resources.

Urban rivers are valuable elements of urban ecosystems and play a key role in urban socio-economic development. Unfortunately, the functional integrity of urban rivers is being threatened by extensive human activities associated with the social development. Urban river health evaluation is important, as it may provide policy makers with information that is fundamental for river governance and the protection of urban ecosystems. To this purpose, we first constructed an urban river health assessment index system based on the pressure–state–response (PSR) framework. Secondly, we developed an urban river health index (uRHI) using the improved fuzzy matter–element extension assessment model. Finally, we used the uRHI to assess the health state of the Jialu River from 2008 to 2017 in Zhengzhou City, China. The results indicate that the health state of the Jialu River was improved from an unhealthy state in 2008 to a sub-healthy state in 2017. The pressure, state, and response subsystems developed towards a healthier state from 2008 to 2017, thanks to the implementation of a number of actions by the local government. However, the overall health status of the Jialu River is still relatively low. The Jialu River also faces several pressures, such as substantial Chemical Oxygen Demand (COD) emissions and sewage discharge. This paper concludes that it is necessary to further strengthen the health management of the Jialu River and the protection of Zhengzhou’s water environment.

During the flood season, various regions in a watershed often have flood drainage conflicts, when the regions compete for flood drainage rights (FDR). In order to solve this problem, it is very necessary to study the allocation of FDR among various regions in the watershed. Firstly, this paper takes fairness, efficiency and sustainable development as the allocation principles, and comprehensively considers the differences of natural factors, social development factors, economic development factors and ecological environment factors in various regions. Then, an indicator system for allocation of FDR among regions in the watershed is established. Secondly, an entropy weight Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) model is used to construct the FDR allocation model among regions in the watershed. Based on a harmony evaluation model, a harmony evaluation and comparison are carried out on the FDR allocation schemes under three different allocation principles. Finally, taking the Jiangsu section of the Huaihe River watershed as an example, the FDR of eight cities in the watershed are allocated and evaluated to see if the allocation scheme is harmonious. The results show that the allocation scheme of FDR based on the principles of fairness, efficiency and sustainable development has the highest degree of harmony, which can meet the FDR demands in various regions in the watershed, avoid the occurrence of flood drainage conflicts among regions, form an orderly flood drainage situation and promote the harmonious development of the watershed.