Expression of Concerns: AQUA – Water Infrastructure, Ecosystems and Society (2024) 73 (3): 396–406: Total ammonia aeration control (TAAC) theory – An innovative ammonia-based aeration controller, Gregory Budzynski, https://dx.doi.org/10.2166/aqua.2024.209

AQUA — Water Infrastructure, Ecosystems and Society issues a formal withdrawal in relation to the above article by Yuhang Li, Zhifa Zeng and Lisai Yu. This decision has been taken due to concerns related to misconduct of a specific editor and their handling of submissions. The editor has been dismissed from the Editorial Board of AQUA — Water Infrastructure, Ecosystems and Society.

The widespread deployment of smart heterogeneous technologies and the growing complexity in our modern society calls for effective coordination of the interdependent lifeline networks. In particular, operation coordination of electric power and water infrastructures is urgently needed as the water system is one of the most energy-intensive networks, an interruption in which may quickly evolve into a dramatic societal concern. The closely-intertwined ecosystem of water and power infrastructures is commonly known as water-energy nexus. This paper develops a novel analytic for uncertainty-aware day-ahead operation optimization of the interconnected power and water systems (PaWS). Joint probabilistic constraint (JPC) programming is employed to capture the uncertainties in wind resources and water demand forecasts. The proposed integrated stochastic model is presented as a non-linear non-convex optimization problem, where the non-linear hydraulic constraints in the water network are linearized using piece-wise linearization technique, and the non-convexity is efficiently tackled with a Boolean solution methodology to convert the proposed model with JPCs to a tractable mixed-integer linear programming (MILP) formulation that can be quickly solved to optimality. The suggested framework is applied to a 15-node commercial-scale water network jointly operated with a power transmission system using a modified IEEE 57-bus test system. The numerical results demonstrate the of the proposed stochastic framework, resulting in cost reduction (13% on average when compared to the traditional setting) and energy saving of the integrated model under different realizations of uncertain renewable energy sources (RESs) and water demand scenarios. Additionally, the scalability of the proposed model is tested on a modified IEEE 118-bus test system connected to five water networks.

AQUA — Water Infrastructure, Ecosystems and Society issues a formal withdrawal in relation to the above article by Abhijeet Das. This decision has been taken as the authors failed to address satisfactorily concerns over the originality of the research.

Corrigendum: <i>AQUA — Water Infrastructure, Ecosystems and Society</i>, 71 (10), 1127–1147: Assimilative capacity and water quality modeling of rivers: a review, https://doi.org/10.2166/aqua.2022.063

Corrigendum: <i>AQUA — Water Infrastructure, Ecosystems and Society</i> 73 (7), 1389–1405: Optimized phased planning for dynamic rehabilitation of integrated municipal infrastructure, Amin Minaei, Soliman Abusamra, Mohsen Hajibabaei, Dragan Savic, Aaron C. Zecchin, Enrico Creaco and Robert Sitzenfrei, https://dx.doi.org/10.2166/aqua.2024.083

Expression of Concern: AQUA – Water Infrastructure, Ecosystems and Society 1 March 2024; 73 (3): 688–706: Construction of community health care integration using artificial intelligence models, Chen Zhou, Ping Zhou, Xuan Xiaolan

The authors regret that funding information was not included in their original paper and apologise for any inconvenience caused. Funding information can be found below and has also been updated on the paper online.

&amp;lt;p&amp;gt;New dams can alter river flow regimes impacting downstream benefits and multi-sector services from water infrastructure and ecosystems. Impacts can be unpredictable in complex transboundary river basins that do not follow standardised operating rules nor have extensive historical data. In this case it is more difficult to assess the consequences of new infrastructure and provide a structured approach to achieve cooperative operating strategies to avoid transboundary water conflicts. This study presents a framework to evaluate the benefits of cooperation on managing new dams in transboundary multi-sector river basins that do not have formal cooperating strategies. A case study of the new Pwalugu Multipurpose Dam (PMD) located in Ghana&amp;amp;#8217;s Volta river basin is provided. The PMD could impact downstream riverine livelihood, ecosystem services, and water infrastructure like the downstream Aksomobo hydropower plant, the country's largest installed generation plant (1,020 MW). Also, the PDM could be impacted by future irritation developments of the Bagre Dam, an existing upstream dam managed in Burkina Faso. We show that a non-cooperative operation between the PMD and the Bagre dam in Burkina Faso could reduce inflows into the Akosombo dam, negatively impacting national hydropower generation. Also, a non-cooperative operation could decrease floods in Northern Ghana, impacting environmental services and local communities that depend on flood recession activities. We show that cooperative infrastructure management achieved by the proposed approach could offset possible negative impacts produced by the new PMD.&amp;lt;/p&amp;gt;

Retraction: <i>AQUA – Water Infrastructure, Ecosystems and Society</i> 73 (3): 688–706: Construction of community health care integration using artificial intelligence models, Chen Zhou, Ping Zhou and Xuan Xiaolan, https://dx.doi.org/10.2166/aqua.2024.038

Corrigendum: <i>AQUA — Water Infrastructure, Ecosystems and Society</i> 72 (5), 593–607: Techno-economic analysis of a hybrid electrodialysis–batch reverse osmosis process for brackish water desalination, Dipak Ankoliya, Anurag Mudgal, Manish Kumar Sinha, Vivek Patel and Jatin Patel, https://dx.doi.org/10.2166/aqua.2023.088

The integrated role of water in ecosystems and, in particular, in agroecosystems, as well as the multiple uses of water - across various sectors that have increasing demands, have been widely recognized. But regions and institutions are still struggling to resolve issues around water - be it scarcity, accessibility or degradation. Mostly, they are caught in conventional institutional and policy frameworks that have been set up based more on sectoral than on cross-sectoral principles, thus preventing them from achieving the ultimate goal of sustainability. This chapter analyses the current and future challenges related to water availability and water use for agriculture from this perspective. It looks at water quantity and quality, water infrastructure, and related governance and institutional aspects, using case studies from basins in different geographic regions.

From David LaFrance, CEO, AWWA: Most recently, the Last Drop column has focused on how AWWA's Water 2050 initiative is charting the course of water to the year 2050. A critical part of the initiative is making sure many voices—especially the voices of water's current young professionals (YPs)—are framing this forward-looking strategy. When I talk to water's YPs, I am left with confidence about the future. They are bold, smart, and visionary, and 10 of them have paired up and are initiating a Last Drop Takeover. What this means is, for the next five Last Drop columns, you will hear directly from them about their thoughts of the future. In this inaugural Last Drop Takeover, Progga Chirontoni and Eric Kong paint a clear vision of what needs to be done and, importantly, why. Progga is a water/wastewater engineer with HDR Engineering. She has a master's degree in environmental and water resources engineering and a bachelor's degree in chemical engineering and mathematics. Eric is a project engineer with Freese and Nichols Inc., with more than six years of experience in the design and construction of water production and water resource recovery facilities. Here is what they have to say about the future of water. As we approach the increasingly hot days of summer, two routines are synonymous with this season: water restrictions and road trips—as disparate as they may seem, there is a connection. When you travel across this country, you can seamlessly pass through a town with a population smaller than your local high school to a city that stretches for miles. Even those small communities are part of our world, filled with people who rely on water as much as the next person. Every one of these communities is a crucial element of our water ecosystem and ultimately the future of water. According to AWWA's 2023 State of the Water Industry report, surveyed utilities agreed on the top three issues facing the water industry: (1) renewal of aging water infrastructure, (2) long-term drinking water supply availability, and (3) financing for capital improvements. These issues are not future projections but challenges that we face today. A practical example regarding infrastructure financing is the issue smaller utilities face with dwindling populations. According to the US Environmental Protection Agency's (EPA's) “Small Drinking Water Systems Research and Development,” there are more than 143,000 active public water systems in the United States; of those, 97% are considered small systems under the Safe Drinking Water Act, meaning they serve 10,000 or fewer individuals. These small systems are constrained by limited resources, including staff, revenue, and equipment redundancy, but they still are responsible for maintaining and replacing their community's water infrastructure. When these utilities face significant financial hardships, they can quickly fall into a feedback loop, where utility revenue is limited, repairs are postponed, infrastructure fails, and the cycle begins again. Just as this challenge exists, the opposite is just as true with areas facing rapid growth, struggling to maintain resources to keep pace with expanding populations. These and other issues, including water supply reliability, the dearth of a water workforce, a shifting environment due to climate change, and the increased need for innovative technologies, exemplify the crossroads we are at in the water industry. As we forge ahead into the future, the question that humanity has faced when a challenge arises remains the same: what do we do now? How do we face the growing challenges of water scarcity and equity? These issues need to be addressed by us—water professionals—in collaboration with local communities. We do this work not for ourselves but for the people around us. Our hope for the future is more than bare-minimum solutions; it involves thoughtful plans that enrich current and future generations. This goal requires all water professionals to take part in this endeavor, with each individual seeking to solve their puzzle piece for the common goal of protecting public health and the environment through the effective management of water. Nothing is too daunting when we all work together to face these challenges and develop solutions.

Humanity has been modifying the natural water cycle by building large-scale water infrastructure for millennia. For most of that time, the principles of hydraulics and control theory were only imperfectly known. Moreover, the feedback from the artificial system to the natural system was not taken into account, either because it was too small to notice or took too long to appear. In the 21st century, humanity is all too aware of the effects of our adaptation of the environment to our needs on the planetary system as a whole. It is necessary to see the environment, both natural and hman-made as one integrated system. Moreover, due to the legacy of the past, the behaviour of the man-madeparts of this system needs to be adapted in a way that leads to a sustainable ecosystem. The water cycle plays a central role in that ecosystem. It is therefore essential that the behaviour of existing and planned water infrastructure fits into the natural system and contributes to its well-being. At the same time, it must serve the purpose for which it was constructed. As there are no natural feedbacks to govern its behaviour, it will be necessary to create such feedbacks, possibly in the form of real-time control systems. To do so, it would be beneficial if all persons involved in the decision process that establishes the desired system behaviour understand the basics of control systems in general and their application to different water systems in particular. This article contains a discussion of the prerequisites for and early development of automatic control of water systems, an introduction to the basics of control theory with examples, a short description of optimal control theory in general, a discussion of model predictive control in water resource management, an overview of key aspects of automatic control in water resource management, and different types of applications. Finally, some challenges faced by practitioners are mentioned.

Extreme precipitation events pose significant challenges to water resources, agriculture, infrastructure, public health, ecosystems, energy production, fishing, timber production, and other rain-dependent socioeconomic sectors across Eastern Africa, threatening the environment and regional livelihoods. This study analyzes spatial and temporal trends of extreme precipitation in Eastern Africa from January 1981 to 2023, using high-resolution CHIRPS data. Key extreme precipitation indices, including R10mm, R75p, and SDII, were calculated to assess variations in the frequency, intensity, and contribution of extreme rainfall events. The temporal analysis reveals a statistically significant increasing trend in January precipitation (0.844 mm/year, p = 0.0191), confirmed by Sen’s Slope (0.74 mm/year). R10mm increased by 0.036 days/year (p = 0.0079), with Sen’s Slope estimating 0.04 days/year. R75p showed a rise of 0.025 days/year (p = 0.0113), with Sen’s Slope at 0.02 days/year. SDII exhibited the most significant trend, increasing by 0.056 mm/day per year (p = 0.0002), with Sen’s Slope at 0.06 mm/day per year. These results indicate a rise in extreme precipitation in Eastern Africa, increasing the risk of flooding and other climate-related hazards. Spatial analysis shows distinct regional variations, with Southern Tanzania, Mozambique, Malawi, Zambia, Zimbabwe, and Madagascar exhibiting statistically significant increasing trends in January precipitation and extreme precipitation indices. These regions are becoming more vulnerable to flooding and other climate-related hazards. Moreover, correlation analysis identifies significant links between global SST anomalies and extreme precipitation trends, demonstrating the influence of large-scale climate drivers. The study indicates the growing intensity and frequency of extreme precipitation in parts of Eastern Africa, significantly influenced by the South Pacific Convergence Zone (SPCZ). This necessitates a deeper understanding of SPCZ dynamics and their impacts on precipitation patterns to enhance climate prediction and develop adaptive strategies for mitigating extreme weather events. Such efforts will contribute to safeguarding water resources, agriculture, infrastructure, public health, energy production, fisheries, transportation, and livelihoods across the region.

This paper shares a vision that sustainable water supply requires resilient water infrastructures which are presumably in the centralized control and decentralized execution (CCDE) mode with multiscale resilience. The CCDE should be planned based on the multiscale structure of water infrastructures, in which the systems are divided into a number of hierarchically organized subsystems. The CCDE allows independent execution of all subsystems under normal situations yet coordination of subsystems at different scales to mitigate any disturbances during failure events, i.e. the multiscale resilience. This vision is discussed in detail for water distribution systems (WDSs). Specifically, the conceptual design of the multiscale CCDE is described, and progress on understanding the multiscale structures in WDSs is summarized based on the literature review. Furthermore, a few theories consistent with the multiscale CCDE concept are discussed which include the decomposition theorems, fractal theory, control theories, and complex network theory. The next step in the vision will be to identify the optimal multiscale structure for the CCDE based on the best trade-off of different goals of WDS analysis and management. This process needs support from not only innovative modelling tools and extensive datasets and theories but also inspiring exemplar systems, e.g. natural systems.