Water resources management in the urban agglomeration of the Lake Biwa region, Japan: An ecosystem services-based sustainability assessment

Waterbody loss due to urban expansion of large Chinese cities in last three decades

Urban waterbodies are one of the most pertinent issues involved in multiple aspects of Sustainable Development Goals (SDGs). However, waterbodies in large Chinese cities are highly vulnerable to urban-land expansion, which is mostly due to economic development, population growth, and rural-urban migration. In this work, we selected 159 Chinese cities of over one million in population to investigate the encroachment on waterbodies due to rapid urbanization from 1990 to 2018. Overall, 20.6% of natural waterbody area was lost during this period to urban expansion, and this fraction varied from city to city which was related to waterbody abundance. With the acceleration of urbanization, waterbody occupation is becoming more serious (P < 0.01). However, in all cities, this encroachment has eased since 2010, which justifies the effective implementation of national-scale policies to conserve urban waterbodies. Meanwhile, gains have occurred during urbanization, in addition to the loss of waterbodies. Especially, cities lacking waterbody placed a greater emphasis on ecological factors, whose urban waterbody areas showed an increasing trend. In the future, ecological resources, including waterbody, should be considered in urban planning to provide reasonable protection to waterbodies in the quest for urban sustainability.

Evaluation of Regional Water Resources Management Performance and Analysis of the Influencing Factors: A Case Study in China

Water resources management (WRM) is a global strategic issue. Effectively evaluating WRM performance and analyzing its influencing factors have strong practical significance for improving regional WRM performance. Data envelopment analysis (DEA) is one of the most popular models to measure the efficiency of decision-making units (DMUs). Taking regional WRM performance as efficiency DMUs, this paper proposes the indicator system to quantify WRM performance from the perspectives of resource endowments, economic and technological development, and ecosystem protection. The WRM performance of 31 provincial administrative regions in mainland China from 2013 to 2019 are measured, and the temporal and spatial changes are explored using the window DEA model and the Malmquist index model. Finally, the Tobit model is used to quantitatively analyze the affecting factors. The results indicate that: (1) in 2015 and 2019, WRM performance of Sichuan, Shaanxi, Xinjiang, Inner Mongolia, and Guangxi were slightly higher than that in other years, and the areas with more room for WRM performance improvements were areas with abundant water resources; (2) from 2013 to 2019, China’s overall WRM performance showed a slow rise, and there were obvious fluctuations in 2018; (3) the improvement in WRM performance was primarily the result of an improvement to comprehensive technical efficiency changes (EC), whereas technological progress changes (TC) have largely restricted China’s WRM performance; (4) the main influencing factors of WRM performance in China were as follows: industrial development level, water resources utilization rate, and urban sewage discharge per capita.

Quantifying Ecosystem Services of High Mountain Lakes across Different Socio-Ecological Contexts

Mountain lakes are highly sensitive to global change, requiring sustainable management strategies that support crucial ecosystem services (ES). However, small mountain lakes are rarely in the focus of ES assessments, and indicators are potentially lacking. Therefore, this study aimed at comprehensively assessing key ES of 15 study lakes located in two regions in the European Alps. We involved local stakeholders and experts to identify important ES. We quantified eight ES in non-monetary terms, using 29 indicators based on limnological, spatial and socio-economic data. Finally, we evaluated ES in relation to the socio-ecological context of the study lakes. The most important ES included surface water for non-drinking purposes, maintaining populations and habitats, outdoor recreation, aesthetic value, entertainment and representation, scientific research, education as well as existence, option, or bequest value. Quantitative results indicate varying levels of ES across the study lakes. Based on 12 different socio-ecological variables, we identified four groups of lakes differing also in five ES. Maintaining populations and habitats, aesthetic value as well as existence, option or bequest value were rather independent from the socio-ecological context. Our findings contribute to a deeper understanding of ES of mountain lakes, also supporting the development of sustainable management strategies in mountain regions.

Lake Atitlan: A Review of the Food, Energy, and Water Sustainability of a Mountain Lake in Guatemala

This paper summarizes the findings of an extensive review of literature that was conducted to understand the historical state of the food, energy, and water nexus in the Lake Atitlan basin and to recommend incentive-based, long-term sustainable policies to become a significant driver to Guatemala’s tourism industry and GDP growth. The SWAT (Soil and Water Assessment Tool) was implemented in the basin to work towards the goal of simulating nutrient loading. A key conclusion of this review study is for the local population to have advocacy for the “zero wastewater discharge to Lake Atitlan” initiative to bring long-term benefits to lake water quality. One of the recommended policy decisions is to seek external financing from international agencies like the World Bank at low-cost interest (IDA Loans) to implement waste management systems and pay this external debt by putting a small but affordable tax on tourists visiting the lake. Once a culture of zero municipal effluent discharge to Lake Atitlan is adopted by the local population, the livelihood of residents will become sustainable and the standard of living will increase because of improved water and air quality, making Lake Atitlan a haven of tourism for Guatemala and lifting its economy.

Using stable nitrogen isotopes to reproduce the process of the impact of human activities on the lakes in the Yunnan Guizhou Plateau in the past 150-200 years

Nitrogen deposition in lake sediment is an important factor reflecting the evolution of lake environments. Over the past 150-200 years, lakes in China have been affected by natural factors and anthropogenic factors, and nitrogen deposition has increased. As a result, it is critical to reconstruct the spatiotemporal variation trend of nitrogen deposition and analyse the nitrogen source and driving factors. On a regional scale, based on the sediment TN, δ¹⁵N and C: N ratio variation trends, this study analysed the buried nitrogen variation trend in Yunnan-Guizhou Plateau lakes over the past 150-200 years. The effects of lake morphology on nitrogen deposition were also analysed by using natural lake parameters. At the watershed scale, the δ¹⁵N isotope in the sediment was used to distinguish the sediment sources. On this basis, this study analysed the relationship between nitrogen deposition in nine lakes and the socioeconomic conditions during 1949-2010. The results show that (1) during the last 150-200 years, the TN, δ¹⁵N and the C: N ratio in the sediments increased. (2) Lake depth and area are the main natural factors affecting the extent of nitrogen deposition. (3) Before 1950, the nitrogen in the lake sediments in the region was sourced mainly from natural sources such as precipitation, woodland, grassland and aquatic plants. After 1950, man-made sources such as sewage and farmland became the main sources of nitrogen. (4) Human social and economic activities have an increasingly significant influence on the lake water environment in the Yunnan-Guizhou Plateau and are also the main factors leading to the deterioration of the aquatic environment.

Assessing Sustainable Rural Development Based on Ecosystem Services Vulnerability

Sustainable Rural Development is essential to maintain active local communities and avoid depopulation and degradation of rural areas. Proper assessment of development in these territories is necessary to improve decision-making and to inform public policy, while ensuring biodiversity conservation and ecosystem services supply. Rural areas include high ecological value systems but the vulnerability of environmental components in development indicators has not been sufficiently pinpointed. The main objective of this work was to propose a new sustainable rural development composite indicator (nSRDI) while considering an environmental dimension indicator based on ecosystem services vulnerability and social and economic dimension indicators established using a sequentially Benefit of the Doubt-Data Envelopment Analysis (BoD-DEA) model. It aimed also to test effects of weighting methods on nSRDI. The composite indicator was applied to 10 regions (comarcas) in the Huesca province, Spain, producing a ranking of regions accordingly. The indicator was further tested through the analysis of the effect of an equal and optimum weighting method on scores and rankings of regions. Results showed substantial differences in nSRDI scores/rankings when vulnerability was added to the process, suggesting that the environmental dimension and the perspective from which it is conceived and applied matters when addressing sustainable rural development.

A simulation-based bi-level multi-objective programming model for watershed water quality management under interval and stochastic uncertainties

A simulation-based interval stochastic bi-level multi-objective programming (SISBLMOP) model was proposed in this research, through integrating the global nutrient export from watersheds model, interval parameter programming and stochastic chance-constrained programming into a general bi-level multi-objective programming framework. The SISBLMOP model can handle multiple uncertainties expressed as discrete intervals and probability density functions in both the simulation and optimization processes. System complexities, including the hierarchy structure of upper- and lower-level decision makers, can also be addressed in the model. The proposed model is applied to a real-world case study of the Xinfengjiang Reservoir Watershed in South China to identify the satisfactory implementation levels of multiple best management practices (BMPs). The model results show that multiple BMP schemes for water quality management can be obtained under different upper- and lower-level decision-making and risk-violation scenarios, reflecting the cooperation and gaming results of the two-level decision makers. Consequently, the corresponding BMP implementation costs are acceptable to both the upper- and lower-level decision makers. The model is widely applicable and can be effectively used for water quality management under multiple uncertainties and complexities.

Stochastic differential game for management of non-renewable fishery resource under model ambiguity

A new bio-economic model for managing population of non-renewable inland fishery resource in uncertain environment is presented. Population dynamics of the resource is described with stochastic differential equations (SDEs) having ambiguous growth and mortality rates. The performance index to be maximized by the manager of the resource while minimized by nature is presented in the context of differential game theory. The dynamic programming principle leads to a Hamilton-Jacobi-Bellman-Isaacs (HJBI) equation that governs the optimal resource management strategy under the ambiguity. The main contribution of this paper is a series of theoretical analysis on the reduced HJBI equation for non-renewable fishery resources in a broad sense, indicating that the ambiguity critically affects the resulting optimal controls. Practical implications of the theoretical analysis results are also presented focusing on artificially hatched Plecoglossus altivelis (Ayu), an important inland fishery resource in Japan.