Identifying priority management areas (PMAs) through assessing integrated eco-environmental risk (IER) of watersheds is vital for efficient integrated watershed management (IWM). However, there is a lack of effective tools to support IWM. A novel framework, which couples the analytical network process with the mean-square deviation decision method to quantify reciprocal feedbacks between ecosystems and socio-economic systems for assessing IER, was developed to identify PMAs for IWM through a case study in the upper Beiyun River watershed, China. The results show that water pollution, water resources, soil loss, hazards (i.e., floods, debris flows, collapses, and landslides), and vegetation degradation are noticeable environmental problems in the watershed. Water pollution, floods, and vegetation degradation risks are high in the southeast plain areas and low in the northwest mountainous areas of the watershed, while the other eco-environmental risks are opposite that of the three risks. The soil loss is mainly dominated by negligible class with a mean of 10.87 (t·km−2·yr−1). The weights of water pollution risk and socio-economic indicator for IER are 0.2906 and 0.1837, respectively. It indicates that water pollution control is crucial for IWM, and socio-economic systems have a significant impact on IER. The PMAs, which are identified as zones with extremely high IER values, account for 6.46 % (72.91 km2) of the watershed. They are centrally distributed in the southeastern areas with high risks of both water pollution and vegetation degradation caused by large population density. The framework provides an effective tool to assess IER and identify PMAs for IWM.
Watersheds are social-ecological systems where humans and other organisms interact with the physical environment and each other (Mosaffaie et al., 2021), and provide many ecosystem services such as nutrient cycles, energy transfer, water supply, carbon storage, and habitats (Lu et al., 2018). Watersheds are considered as the most effective units for managing the complex relationships among the waterland-air-plant-human nexus to support regional sustainable development (Li et al., 2018; RazaviToosi and Samani, 2019). Healthy watersheds play a vital role in ensuring the sustainability of social-economic systems and improving the well-being of humans (Ervinia et al., 2019; Moradi and Limaei, 2018). Healthy watersheds have high reliability and resilience, which suggests that watersheds must be restored and controlled a healthy level through integrated eco-environmental risk assessment for implementing effective watershed restoration and management (Duan et al., 2022). These restored watersheds could be reduced the impact of climate change and human activities on watershed ecosystems and sustainable development (Liu et al., 2020a). However, many watersheds are degrading or have the potential to become impaired because of climate change, urbanization, and the rapid development of industry, agriculture and tourism (Lerch et al., 2015; Sanches Fernandes et al., 2018; Zhang et al., 2022). Consequently, there are various environmental problems in many watersheds, which have resulted in forgone watershed ecosystem service functions.
To restore degraded ecological functions, integrated watershed management (IWM) is increasingly adopted in many regions around the world (Mekonnen et al., 2021; Satalov ˇ a and Kenderessy, 2017 ´ ). IWM is a holistic method to optimize the complex interactions between ecosystems and socio-economic systems for ensuring sustainable development (Arteaga et al., 2020; Kang and Park, 2015). For instance, the Rhine River was regarded as “a dead river” in the 1970 s because of severe ecoenvironmental problems resulting from rapid industrialization and population growth (Dieperink, 2000). With the implementation of an IWM program called the Rhine action plan, the ecological functions of the Rhine River watershed gradually recovered (Wang et al., 2016). It has been reported that the Poyang Lake watershed has experienced serious environmental problems, such as water pollution and soil loss, due to the rapid increase in population since the 1980 s (Liu et al., 2015). After the implementation of the IWM, the ecosystem of the Poyang Lake watershed was improved (Chen et al., 2005). Teka et al. (2020) indicated that implementing IWM could effectively reduce soil loss rates and increase people’s incomes in the Gule watershed. Brombal et al. (2018) showed that the environmental conditions of the Lihu watershed were improved and that the regional economy increased because of IWM. However, these outcomes were achieved through significant investments in resources, time, and manpower due to a lack of proper methods in IWM, leading to low cost-effectiveness and efficiency of IWM (Mosaffaie et al., 2021; Sun et al., 2016). It is still a challenge to improve the efficiency of IWM for watersheds with limited resources.
This study developed a novel framework to quantitatively identify priority management areas (PMAs) for efficient integrated watershed management (IWM) through assessing integrated eco-environmental risk (IER) of watersheds. This framework was applied and tested in the upper Beiyun River watershed of Beijing, China. The results showed that there are five noticeable environmental problems (i.e., water pollution, water resources, soil loss, hazards, and vegetation degradation) in this watershed. The high-risk regions of both water pollution and vegetation degradation are located in the southeastern plain areas, which are covered by urban land, cultivated land, and rural residential land. The water yield changes from 262.29 mm⋅pixel− 1 to 566.86 mm⋅pixel− 1 , and the soil loss is mainly dominated by negligible class with a mean of 10.87 (t⋅km− 2 ⋅yr− 1 ). Debris flows, collapses, and landslides occur frequently in the northwestern mountainous areas with large slopes between 25◦ and 87◦, while the high-risk regions of floods are distributed in the southeastern plain areas. The weight of water pollution for the IER is the largest (0.2906), followed by the weights of socio-economic indicator (0.1837), hazards (0.1640), vegetation degradation (0.1360), soil loss (0.1346), and water resources (0.0911), indicating that water pollution control is crucial for IWM in the watershed. It also implies that the socio-economic systems have a significant impact on the IER and determine the economic capacity for IWM. The PMAs, which are identified as zones with extremely high IER values, account for 6.46 % (72.91 km2 ) of the watershed. They are centrally distributed in the southeastern areas with high risks of both water pollution and vegetation degradation caused by large population density. With flexible structure, the framework has the potential to be applicable in various watersheds to identify PMAs through assessing IER for efficient IWM.