Protecting environmental flows to achieve long-term water security

A conceptual framework for analysis of environmental security and development based on source and flow concepts

Researches on security and development (SD) is interrelated and essential for ecosystem especially human survival but commonly separated and diverged to multiple scales and fields. Thus, a more integral and fundamental theoretical framework is required for following better analysis of both of the dual concepts, like the United Nations Sustainable Development Goals need the more innovative interdisciplinary theoretical framework to face comprehensive challenges of both sustainable development and security in nowadays. Therefore, this research aims to integrate the study of the two aspects and proposes an abstract, general fundamental framework for analysis of environmental impact on them. Based on theory of Environmental Economic Geography (EEG), Ecosystem Services (ES) and concepts of 'Source-Access-Flow' (SAF), 'Cell model' with its 'Cell Compass' approach for analysis of environmental spatial pattern and corresponding strategies was established for such framework. The analysis results of Cell model classified and ranked different typical environmental patterns as well as corresponding actions, so as to address environmental pattern assessment and optimize strategies for better development situation. Further, possible changes were discussed and calculation methods of development level and efficiency were defined.

Effective management of urban water resources under various climate scenarios in semiarid mediterranean areas

Climate change has a significant impact on water resources, making it essential to re-evaluate water management strategies and incorporate climate scenarios in assessments. The Municipal Department of Aigeiros is located in the northern part of Greece. Water consumption is high in Aigeiros and the increased future temperatures projected during the summer period will create significant pressures on water resources. The water resources management study of the region is carried out using the simulations of the RCA4 Regional Climate Model (RCM) driven by the HadGEM-ES global climate model of the Met Office Hadley Centre (MOHC) under 3 different climate emission scenarios, namely RCP 2.6, RCP 4.5 and RCP 8.5. For the simulation of the urban water balance of Aigeiros, Komotini, Greece and the assessment of water demand and supply for three climate scenarios (RCP 2.6, 4.5, and 8.5) over a 30-year period, the Aquacycle software was used. The data used in the assessment included projected climatic conditions for the area (i.e., precipitation and evapotranspiration), domestic water consumption, and natural and spatial characteristics. The results indicate that drinking water demand is likely to increase in the coming decades for RCP 4.5 (1323 m3/d for 2041-2050) and RCP 8.5 (1330 m3/d for 2041-2050) scenarios compared to 2020 (1320 m3/d). However, simulations for water supply suggest an increase in groundwater recharge in the future, but also the potential for long drought periods during summer months in RCP 4.5 and RCP 8.5 scenarios. The simulation results show both the current situation and the climate scenarios and can be the reference basis for recording the different types of water consumption in urban areas. Therefore, it is possible to control and predict how much of the total consumption is due to the consumer usage profile within a household or to the irrigation needs of green areas in line with the climatic conditions, consumer behavior and technical parameters.

An electricity market-based approach to finance environmental flow restoration

As environmental flow demands become better characterized, improved water allocation and reservoir operating solutions can be devised to meet them. However, significant economic trade-offs are still expected, especially in hydropower-dominated basins. This study explores the use of the electricity market as both an institutional arrangement and an alternative financing source to handle the costs of implementing environmental flows in river systems managed for hydropower benefits. A framework is proposed to identify hydropower plants with sustainable operation within the portfolio of power sources, including a cost-sharing mechanism based on the electricity market trading to manage a time-step compensation fund. The objective is to address a common limitation in the implementation of environmental flows by reducing the dependence on government funding and the necessity for new arrangements. Compensation amounts can vary depending on ecosystem restoration goals (level of flow regime restoration), hydrological conditions, and hydropower sites characteristics. The application in the Paraná River Basin, Brazil, shows basin-wide compensation requirements ranging from zero in favorable hydrological years to thousands of dollars per gigawatt-hour generated in others. Each electricity consumer's contribution to the compensation fund is determined by their share of energy consumption, resulting in values ranging from cents for residential users to thousands of dollars for industrial facilities. Finally, the compensation fund signals the economic value of externalities in energy production. For residential users, achieving varying levels of ecosystem restoration led to an electricity bill increase of less than 1 %. For larger companies, the increase ranged from less than 1 %-12 %.

The alarming state of Central Chile's groundwater resources: A paradigmatic case of a lasting overexploitation

Ensuring water supply under climate change scenarios is a global concern, and groundwater resources play a crucial role. Aquifer depletion is a worldwide trend, and Chile is no exception. Through a statistical approach with strong hydrogeological criteria, the groundwater overexploitation phenomenon is studied in Central Chile, the most populated region in this mountainous country. With this purpose, we assess the evolution of groundwater levels and pumping between 1970 and 2020 by analysing 26,065 groundwater rights and 222 observation wells. Withdrawals increased from 498 hm3 in 1970 to 8883 hm3 in 2020. We recognised two general trends in groundwater levels: a quasi-steady state hydrodynamic regime pre-1988 and sustained decline post-1988, exacerbated since 2010 with the start of the Megadrought. Although groundwater recharge is expected to decrease during this severe drought, the declining trend strongly correlates with pumping but not with precipitation changes. Climate forcing is usually invoked to warrant the dramatic depletion of groundwater resources, but we demonstrated that all analysed aquifers have been overexploited since much earlier than 2010. Finally, the Chilean aquifers' overexploitation is a clear example of the consequences of prioritising the water offer over the water demand regulation, which hinders the United Nations' sustainable development goals accomplishment.

Application and Comparison of Different Models for Quantifying the Aquatic Community in a Dam-Controlled River

In order to develop a better model for quantifying aquatic community using environmental factors that are easy to get, we construct quantitative aquatic community models that utilize the different relationships between water environmental impact factors and aquatic biodiversity as follows: a multi-factor linear-based (MLE) model and a black box-based 'Genetic algorithm-BP artificial neural networks' (GA-BP) model. A comparison of the model efficiency and their outputs is conducted by applying the models to real-life cases, referring to the 49 groups of seasonal data observed over seven field sampling campaigns in Shaying River, China, and then performing model to reproduce the seasonal and inter-annual variation of the water ecological characteristics in the Huaidian (HD) site over 10 years. The results show that (1) the MLE and GA-BP models constructed in this paper are effective in quantifying aquatic communities in dam-controlled rivers; and (2) the performance of GA-BP models based on black-box relationships in predicting the aquatic community is better, more stable, and reliable; (3) reproducing the seasonal and inter-annual aquatic biodiversity in the HD site of Shaying River shows that the seasonal variation of species diversity for phytoplankton, zooplankton, and zoobenthos are inconsistent, and the inter-annual levels of diversity are low due to the negative impact of dam control. Our models can be used as a tool for aquatic community prediction and can become a contribution to showing how quantitative models in other dam-controlled rivers to assisting in dam management strategies.