Hasil untuk "River, lake, and water-supply engineering (General)"

ZHANG Chengyan, BAO Lingling, YE Yizhou et al.

To overcome the limitations of previous analyses examining drought evolution from solely temporal or spatial perspectives and to better capture the complete developmental process of meteorological drought events, this study employs a three-dimensional (3D) drought identification method integrating spatiotemporal connectivity, based on the SPI-3, to systematically reveal the spatiotemporal dynamic evolution patterns of meteorological drought events in Wenzhou City, a pivotal coastal area in southeastern China. The methodology involves defining drought events as coherent spatiotemporal clusters where the SPI-3 is below the moderate drought threshold (-1), meticulously tracking their initiation, migration, expansion, contraction, and termination. The analysis utilizes high-quality monthly precipitation data (1961-2019) from 22 meteorological stations, spatially interpolated to a 1-km resolution grid, alongside SRTM DEM data for topographical context. The core 3D identification process comprises two key steps: first, identifying independent drought patches in each month by merging contiguous drought grids and applying an area threshold (≈1.6% of the study area, 193.6 km²); second, temporally connecting patches across consecutive months based on spatial overlap exceeding this threshold, thereby constructing 3D drought structures characterized by duration, area, intensity (volume), and centroids. Results identify 131 distinct meteorological drought events in Wenzhou from 1961 to 2019. Temporally, overall trends in drought duration, area, and intensity show a fluctuating decline, with distinct phases: a significant decrease before 1995, an increase followed by a decrease between 1995 and 2005, and relatively stable duration/intensity but fluctuating area post-2005, indicating a shift towards more widespread but less intense/short-lived events. Seasonally, droughts exhibit high incidence in summer (27.53%) and autumn (26.96%), with October (13.7%) and July (13.0%) being the peak months. Spatially, drought centers are predominantly concentrated in inland areas farther from the coast, with Yongjia, Ouhai, Ruian, and Pingyang districts experiencing particularly long-duration and high-intensity events, highlighting a clear correlation with topography and land-sea position. Analysis of the ten most severe events and detailed 3D case studies demonstrates that the reconstructed spatiotemporal evolution—including development paths, changing spatial footprints, and centroid migration—aligns remarkably well with historical drought records from Wenzhou. This consistency robustly validates the reliability and practical utility of the proposed SPI-based 3D identification method. Consequently, this study not only provides novel insights into the intricate spatiotemporal dynamics of droughts in a complex coastal environment but also offers a refined methodological framework for improved regional drought monitoring, dynamic tracking, and early warning. The findings furnish a detailed scientific basis for formulating targeted drought risk prevention, control strategies, and resilience enhancement in Wenzhou and similar monsoonal coastal regions.

Alexander Korn, Lea Zaruchas, Chetan Arora et al.

Large Language Models, particularly decoder-only generative models such as GPT, are increasingly used to automate Software Engineering tasks. These models are primarily guided through natural language prompts, making prompt engineering a critical factor in system performance and behavior. Despite their growing role in SE research, prompt-related decisions are rarely documented in a systematic or transparent manner, hindering reproducibility and comparability across studies. To address this gap, we conducted a two-phase empirical study. First, we analyzed nearly 300 papers published at the top-3 SE conferences since 2022 to assess how prompt design, testing, and optimization are currently reported. Second, we surveyed 105 program committee members from these conferences to capture their expectations for prompt reporting in LLM-driven research. Based on the findings, we derived a structured guideline that distinguishes essential, desirable, and exceptional reporting elements. Our results reveal significant misalignment between current practices and reviewer expectations, particularly regarding version disclosure, prompt justification, and threats to validity. We present our guideline as a step toward improving transparency, reproducibility, and methodological rigor in LLM-based SE research.

Tanja E. J. Vos, Tijs van der Storm, Alexander Serebrenik et al.

Software engineering is the invisible infrastructure of the digital age. Every breakthrough in artificial intelligence, quantum computing, photonics, and cybersecurity relies on advances in software engineering, yet the field is too often treated as a supportive digital component rather than as a strategic, enabling discipline. In policy frameworks, including major European programmes, software appears primarily as a building block within other technologies, while the scientific discipline of software engineering remains largely absent. This position paper argues that the long-term sustainability, dependability, and sovereignty of digital technologies depend on investment in software engineering research. It is a call to reclaim the identity of software engineering.

Mairieli Wessel, Daniel Feitosa, Sangeeth Kochanthara

Rising publication pressure and the routine use of generative AI tools are reshaping how software engineering research is produced, assessed, and taught. While these developments promise efficiency, they also raise concerns about skill degradation, responsibility, and trust in scholarly outputs. This vision paper employs Design Fiction as a methodological lens to examine how such concerns might materialise if current practices persist. Drawing on themes reported in a recent community survey, we construct a speculative artifact situated in a near future research setting. The fiction is used as an analytical device rather than a forecast, enabling reflection on how automated assistance might impede domain knowledge competence, verification, and mentoring practices. By presenting an intentionally unsettling scenario, the paper invites discussion on how the software engineering research community in the future will define proficiency, allocate responsibility, and support learning.

LI Meng-yu, LÜ Chao-fan, LU Jin-you, LUAN Hua-long, ZHU Yong-hui, ZHU Jia-xi, GE Jian-zhong, Makiko Iguchi

[Objective] Freak wave is a marine disaster characterized by extremely large wave height, strong nonlinearity, and high destructiveness. The results of wave superposition method for simulating freak waves are influenced by multiple parameters, and the sensitivity and interaction mechanisms of these factors require systematic investigation. [Methods] Based on a self-developed viscous-flow numerical wave tank, we conducted a numerical simulation on the generation of freak waves and their influencing factors. First, the reliability of the numerical model was verified against physical experimental data. Subsequently, the harmonic separation method was employed to examine the influence of wave group nonlinearity on wave surface deformation, focusing characteristics, and frequency spectrum structure. Through numerical experiments, the effects of key parameters—including spectral type, number of constituent waves, spectral bandwidth, spectral peak frequency, and water depth—were investigated. [Results] 1) During the generation of a freak wave, wave-wave nonlinear interactions caused energy to transfer from the primary frequency to both high and low frequencies, resulting in significant spectral broadening. Low-frequency free pseudo-harmonics propagated faster, leading to an actual wave height slightly larger than the theoretical value. High-frequency bound harmonics formed a tail wave, which had a minor influence on the shape of the main peak. 2) The spectral type significantly influenced the wave profile characteristics: the JONSWAP and P-M spectra, with concentrated energy, tended to generate freak waves with steep crests. The CWA spectrum produced gentle wave profiles; the CWS spectrum yielded the smallest focused amplitude. 3) The number of constituent waves affected the focusing recurrence period. An insufficient number could generate secondary focused waves. It was recommended to use 29 constituent waves to balance computational accuracy and efficiency. 4) Under finite water depth conditions, the focused amplitude reached its maximum when the spectral bandwidth was 0.7 Hz, indicating that the amplitude was co-modulated by the spectral bandwidth, water depth, and spectral peak frequency. 5) An increase in the spectral peak frequency enhanced nonlinearity, resulting in wave profile steepening. However, an excessively high frequency led to wave breaking, thereby reducing the amplitude. 6) Water depth influenced the wave profile by altering the dispersion characteristics. A greater water depth resulted in faster wave speed and a higher amplitude, whereas an excessively small water depth readily induced wave breaking. [Conclusion] The main innovations of this research include: establishing a high-precision viscous-flow numerical model capable of accurately simulating the evolution of nonlinear waves including breaking effects; employing the harmonic separation method to reveal the influence mechanism of wave group nonlinearity on wave surface structure and energy distribution; and clarifying the coupling effects of various factors under finite water depth conditions through multi-parameter sensitivity experiments. The findings of this study deepen the understanding of freak wave generation mechanisms, provide an important theoretical basis and parameter selection guidance for laboratory simulation of freak waves.

FU Jian-jun, LI Yun-qi, YUAN Li, CHEN Peng, GONG Rou-yan

[Objective] To address the mismatch between traditional rainfall analysis methods (April to October) for hilly irrigation areas in south China and actual intra-seasonal water demand during rice growth stages (late rice from July to October), this study focuses on intra-seasonal rainfall during the rice growth stages, integrating GIS technology to investigate the water supply reliability of the Maweizao irrigation area. [Methods] Using daily meteorological data from 1989 to 2019 in the irrigation area, the intra-seasonal rainfall frequency analysis method was employed to identify typical representative years and characteristic values for normal years (P=50%), moderately dry years (P=75%), and dry years (P=90%). The FAO Penman-Monteith method and water balance method were then used to calculate the crop water requirements and net irrigation water requirements for rice. [Results]The results showed that: (1) In dry years, the intra-seasonal rainfall during the late rice growth stages (160 mm) accounted for only 21.2% of the total rainfall from April to October (755 mm). Moreover, a mismatch was observed between the rainfall peak (August) and the critical water demand period (booting to heading stage, September). This led to 14% higher net field irrigation water requirements (560 mm) calculated by intra-seasonal rainfall frequency analysis compared to traditional methods, accurately reflecting the typical contradiction in hilly irrigation areas where there was “no rain during water demand periods but excessive rain during non-demand periods.” (2) GIS-based spatial simulations revealed a distinct bimodal structure in the irrigation area during dry years. Croplands near the main water source (Maweizao Reservoir) benefited from sufficient storage capacity (27.02 million m3) and a canal system integrity rate above 85%, achieving a water supply reliability rate greater than 80%, thus forming a high-yield and stable-production core zone. Areas dependent on small reservoirs for water regulation and storage, where storage capacity utilization declined to 60% due to sedimentation, had a water supply reliability rate of 60%-80%. Limited by scattered ponds (406 ponds), insufficient catchment areas (<5 km2 per pond), and damaged main and lateral canals (integrity rate <40%), the overall reliability rates dropped below 40%, posing a high risk of yield reduction. (3) For every 10% increase in water supply reliability rate, late rice yield increased by 35-50 kg per mu(1mu≈666.67 m2), showing a significant positive linear correlation (R2=0.89). When the reliability rate exceeded 80%, soil water content remained stable at 18%-24% (optimal range for rice growth), resulting in yields of 400-500 kg per mu.When the reliability rate fell below 40%, soil water content dropped sharply below 10%, leading to plant wilting or even total crop failure (yield <200 kg per mu). Within the 60%-80% range of reliability rate, each 1 m3 irrigation water increase produced an extra 1.2-1.5 kg of rice, indicating optimal resource use efficiency. [Conclusion] By focusing on intra-seasonal rainfall during rice growth stages, this study reveals the underlying mechanism of irrigation water supply-demand imbalance in hilly irrigation areas and proposes the following three practical strategies. Over 70% irrigation water should be allocated during the booting to heading stages (September) based on crop water requirements, with priority given to areas maintaining water supply reliability rates above 60%. For areas with water supply reliability rates below 40%, the “pond desilting + intelligent water control” project should be implemented to increase small water source utilization rate from 45% to 75%, while restoring main and lateral canals to achieve an integrity rate above 60%. By focusing on intra-seasonal rainfall during rice growth stages, this study provides a scientific basis for precise irrigation management and confirmation of agricultural water use rights in hilly irrigation areas, holding important practical significance for optimizing water resource allocation and enhancing grain production capacity.

Carolyn Seaman, Rashina Hoda, Robert Feldt

The paper entitled "Qualitative Methods in Empirical Studies of Software Engineering" by Carolyn Seaman was published in TSE in 1999. It has been chosen as one of the most influential papers from the third decade of TSE's 50 years history. In this retrospective, the authors discuss the evolution of the use of qualitative methods in software engineering research, the impact it's had on research and practice, and reflections on what is coming and deserves attention.

Max Ofsa, Taylan G. Topcu

Systems engineering (SE) is evolving with the availability of generative artificial intelligence (AI) and the demand for a systems-of-systems perspective, formalized under the purview of mission engineering (ME) in the US Department of Defense. Formulating ME problems is challenging because they are open-ended exercises that involve translation of ill-defined problems into well-defined ones that are amenable for engineering development. It remains to be seen to which extent AI could assist problem formulation objectives. To that end, this paper explores the quality and consistency of multi-purpose Large Language Models (LLM) in supporting ME problem formulation tasks, specifically focusing on stakeholder identification. We identify a relevant reference problem, a NASA space mission design challenge, and document ChatGPT-3.5's ability to perform stakeholder identification tasks. We execute multiple parallel attempts and qualitatively evaluate LLM outputs, focusing on both their quality and variability. Our findings portray a nuanced picture. We find that the LLM performs well in identifying human-focused stakeholders but poorly in recognizing external systems and environmental factors, despite explicit efforts to account for these. Additionally, LLMs struggle with preserving the desired level of abstraction and exhibit a tendency to produce solution specific outputs that are inappropriate for problem formulation. More importantly, we document great variability among parallel threads, highlighting that LLM outputs should be used with caution, ideally by adopting a stochastic view of their abilities. Overall, our findings suggest that, while ChatGPT could reduce some expert workload, its lack of consistency and domain understanding may limit its reliability for problem formulation tasks.

Shavindra Wickramathilaka, John Grundy, Kashumi Madampe et al.

The use of diverse mobile applications among senior users is becoming increasingly widespread. However, many of these apps contain accessibility problems that result in negative user experiences for seniors. A key reason is that software practitioners often lack the time or resources to address the broad spectrum of age-related accessibility and personalisation needs. As current developer tools and practices encourage one-size-fits-all interfaces with limited potential to address the diversity of senior needs, there is a growing demand for approaches that support the systematic creation of adaptive, accessible app experiences. To this end, we present AdaptForge, a novel model-driven engineering (MDE) approach that enables advanced design-time adaptations of mobile application interfaces and behaviours tailored to the accessibility needs of senior users. AdaptForge uses two domain-specific languages (DSLs) to address age-related accessibility needs. The first model defines users' context-of-use parameters, while the second defines conditional accessibility scenarios and corresponding UI adaptation rules. These rules are interpreted by an MDE workflow to transform an app's original source code into personalised instances. We also report evaluations with professional software developers and senior end-users, demonstrating the feasibility and practical utility of AdaptForge.

Fabian C. Peña

Large Language Models (LLMs) are revolutionizing software engineering (SE), with special emphasis on code generation and analysis. However, their applications to broader SE practices including conceptualization, design, and other non-code tasks, remain partially underexplored. This research aims to augment the generality and performance of LLMs for SE by (1) advancing the understanding of how LLMs with different characteristics perform on various non-code tasks, (2) evaluating them as sources of foundational knowledge in SE, and (3) effectively detecting hallucinations on SE statements. The expected contributions include a variety of LLMs trained and evaluated on domain-specific datasets, new benchmarks on foundational knowledge in SE, and methods for detecting hallucinations. Initial results in terms of performance improvements on various non-code tasks are promising.

C. Vörösmarty, D. Sahagian

Nikolas Kirschstein, Yixuan Sun

Climate change exacerbates riverine floods, which occur with higher frequency and intensity than ever. The much-needed forecasting systems typically rely on accurate river discharge predictions. To this end, the SOTA data-driven approaches treat forecasting at spatially distributed gauge stations as isolated problems, even within the same river network. However, incorporating the known topology of the river network into the prediction model has the potential to leverage the adjacency relationship between gauges. Thus, we model river discharge for a network of gauging stations with GNNs and compare the forecasting performance achieved by different adjacency definitions. Our results show that the model fails to benefit from the river network topology information, both on the entire network and small subgraphs. The learned edge weights correlate with neither of the static definitions and exhibit no regular pattern. Furthermore, the GNNs struggle to predict sudden, narrow discharge spikes. Our work hints at a more general underlying phenomenon of neural prediction not always benefitting from graphical structure and may inspire a systematic study of the conditions under which this happens.

Eduard C. Groen, Kazi Rezoanur Rahman, Nikita Narsinghani et al.

The farming domain has seen a tremendous shift towards digital solutions. However, capturing farmers' requirements regarding Digital Farming (DF) technology remains a difficult task due to domain-specific challenges. Farmers form a diverse and international crowd of practitioners who use a common pool of agricultural products and services, which means we can consider the possibility of applying Crowd-based Requirements Engineering (CrowdRE) for DF: CrowdRE4DF. We found that online user feedback in this domain is limited, necessitating a way of capturing user feedback from farmers in situ. Our solution, the Farmers' Voice application, uses speech-to-text, Machine Learning (ML), and Web 2.0 technology. A preliminary evaluation with five farmers showed good technology acceptance, and accurate transcription and ML analysis even in noisy farm settings. Our findings help to drive the development of DF technology through in-situ requirements elicitation.

Isnan Fauzan Akrom, Muhammad Fauzi

The 2020 drought led to a reduction in the water supply of the Citarum cascade reservoirs (Saguling, Cirata, and Juanda) due the lowering intensity of rainfall in the catchments of the three reservoirs. Rainfall in late 2020 through February 2021 was much lower than the predicted and historical averages. This caused the water level of the Citarum cascade reservoirs fell to be below normal at the end of December 2020. To meet the water demand, an increase in inflow enhancement is needed, hence the implementation of Weather Modification Technology (WMT) which was carried out on March 12th - April 21st, 2021 in the Citarum watershed, West Java Province. WMT is applied for increasing or decreasing the amount of rainfall by intervening in the cloud growth process, which is carried out by seeding NaCl powder on clouds using an airplane. The purpose of monitoring and evaluation (M&E) of WMT implementation is to collect data, analyze, and evaluate the hydrological conditions of the Citarum cascade reservoirs during WMT implementation. The purpose of M&E is to assess the success of additional reservoir volume due to rainfall during WMT implementation. The M&E is conducted by collecting daily data of the rainfall, water level, and hydrological data of the reservoirs. The data collected each day is used as the basis for the seeding strategy on that day. After the WMT implementation activities are completed, an evaluation of the overall WMT implementation results is continued, which includes analyzing rainfall data, river water level, as well as the inflow, volume, and water level of the reservoir. The results of this study show that WMT implementation could not raise the water level of the three reservoirs to the Normal Operating Limit, but it has succeeded in increasing the reservoir volume by approximately 270 million m3 for Saguling, 201 million m3 for Cirata, and 59 million m3 for Juanda.

T. Ramachandra

The Western Ghats, a range of ancient hills extends between 8° N and 21° N latitude, and 73° E and 77° E longitude(from the tip of peninsular India at Kanyakumari to Gujarat). The Western Ghats runs parallel to the west coast of India, covering approximately 160,000 sq. km, which constitutes less than 5% of India's geographical extent. Numerous streams originate in the Western Ghats, which drain millions of hectares, ensuring water and food security for 245 million people and hence are aptly known as the water tower of peninsular India(Ramachandra and Bharath, 2019; Bharath et al., 2021). The region is endowed with diverse ecological regions depending on altitude, latitude, rainfall, and soil characteristics. The Western Ghats are among the eight hottest hotspots of biodiversity and 36 global biodiversity hotspots with exceptional endemic flora and fauna. Natural forests of Western Ghats have been providing various goods and services and are endowed with species of 4,600+ flowering plants (38% endemics), 330 butterflies (11% endemics), 156 reptiles (62% endemics), 508 birds (4% endemics), 120 mammals (12% endemics), 289 fishes (41% endemics) and 135 amphibians (75% endemics). The Western Ghats, gifted with enormous natural resource potential, and the mandate of sustainable development based on the foundation of prudent management of ecosystems, is yet a reality. Various unplanned developmental programs, which are proclaimed to be functioning on sustainability principles, have only been disrupting the complex web of life, impacting ecosystems, and causing a decline in overall productivity, including four major sectors: forestry, fisheries, agriculture, and water (Ramachandra and Bharath, 2019).The prevalence of barren hilltops, conversion of perennial streams to intermittent or seasonal streams, frequent floods and droughts, changes in water quality, soil erosion and sedimentation, the decline of endemic flora, and fauna, etc. highlights the consequences of unplanned developmental activities with a huge loss to the regional economy during the last century. The development goals need to be ecologically, economically, and socially sustainable, which can be achieved through the conservation and prudent management of ecosystems. Sustainability implies the equilibrium between society, ecosystem integrity, and sustenance of natural resources. Water sustenance in streams and rivers depends on the integrity of the catchment (watershed), as vegetation helps in retarding the velocity of water by allowing impoundment and recharging of groundwater through infiltration (Ramachandra et al., 2020). As water moves in the terrestrial ecosystem, part of it is percolated (recharging groundwater resources and contributing to sub-surface flow during post-monsoon seasons), while another fraction gets back to the atmosphere through evaporation and transpiration. Forests with native vegetation act as a sponge by retaining and regulating water transfer between land and the atmosphere. The mechanism by which vegetation controls flow regime is dependent on various bio-physiographic characteristics, namely, type of vegetation, species composition, maturity, density, root density and depth, hydro-climatic condition, etc. Roots of vegetation help (i) in binding soil, ii) improve soil structure by enhancing the stability of aggregates, which provide habitat for diverse microfauna and flora, leading to higher porosity of the soil, thereby creating the conduit for infiltration through the soil. An undisturbed native forest has a consistent hydrologic regime with sustained flows during lean seasons. Native species of vegetation with the assemblage of diverse native species help in recharging the groundwater, mitigating floods, and other hydro-ecological processes (Ramachandra et al., 2020; Bharath et al., 2021). Hence, it necessitates safeguarding and maintaining native forest patches and restoring existing degraded lands to sustain the hydrological regime, which caters to biotic (ecological and societal) demands. A comparative assessment of people's livelihood with soil water properties and water availability in sub-catchments of four major river basins in the Western Ghats reveals that streams in catchments with > 60% vegetation of native species are perennial with higher soil moisture (Ramachandra et al., 2020). The higher soil moisture due to water availability during all seasons facilitates farming of commercial crops with higher economic returns to the farmers, unlike the farmers who face water crises during the lean season. In contrast, streams are intermittent (6-8 months of water) in catchments dominated by monoculture plantations and seasonal (4 months, monsoon period) in catchments with vegetation cover lower than 30%. The study highlights the need to maintain ecosystem integrity to sustain water. Also, lower instances of COVID 19 in villages with native forests emphasize ecosystems' role in maintaining the health of biota. The need to maintain native vegetation in the catchment and its potential to support people's livelihood with water availability at local and regional levels is evident from the revenue of Rs. Rs.2,74,658 ha-1 yr-1 (in villages with perennial streams and farmers growing cash crops or three crops a year due to water availability), Rs. 1,50,679 ha-1 yr-1 (in villages with intermittent streams) and Rs. 80000 ha-1 yr-1 (in villages with seasonal streams). Also, the crop yield (at least 1.5 to 1.8 times) is higher in agriculture fields due to efficient pollination with the prevalence of diverse pollinators in the vicinity of native forests. The study emphasizes the need for maintaining the natural flow regime and prudent management of watershed to i) sustain higher faunal diversity, ii) maintain the health of water body, and iii) sustain people's livelihood with higher revenues. Hence, the premium should be on conserving the forests with native species to sustain water and biotic diversity in the water bodies, vital for food security. There still exists a chance to restore the lost natural ecosystems through appropriate ecological restoration approaches, with location-specific conservation and management practices to ensure adequate and clean water for all. GDP (Gross Domestic Product), a measure of the current economic well-being of a population, based on the market exchange of material well-being, will indicate resource depletion/degradation only through a positive gain in the economy and will not represent the decline in these assets (wealth) at all. Thus, the existing GDP growth percentages used as yardsticks to measure the development and well-being of citizens in decision-making processes are substantially misleading, yet they are being used. The traditional national accounts need to include resource depletion or degradation due to developmental activities and climate change. The country should move toward adopting Green GDP by accounting for the environmental consequences of the growth in the conventional GDP, which entails monetizing the services provided by ecosystems, the degradation cost of ecosystems, and accounts for costs caused by climate change. The forest ecosystems are under severe threat due to anthropogenic pressures, which are mostly related to the GDP.The appraisal of forest ecosystem services and biodiversity can help clarify trade­-offs among conflicting environmental, social, and economic goals in the development and implementation of policies and to improve the management in order biodiversity.Natural capital accounting and valuation of ecosystem services reveal that forest ecosystems provide (i) provisioning services (timber, fuelwood, food, NTFP, medicines, genetic materials) of Rs 2,19,494 ha-1 yr-1, (ii) regulating services (global climate regulation - carbon sequestration, soil conservation, and soil fertility, water regulation and groundwater recharge, water purification, pollination, waste treatment, air filtration, local climate regulation) of Rs 3,31,216 ha-1 yr-1 and (iii) cultural services (aesthetic, spiritual, tourism and recreation, education and scientific research) of Rs.1,04,561 ha-1 yr-1. Total ecosystem supply value (TESV), an aggregation of provisioning, regulating, and cultural services, amounts to Rs. 6,56,172 ha-1 yr-1, and the Net Present Value (NPV) of one hectare of forests amounts to 16.88 million rupees ha-1. NPV helps in estimating ecological compensation while diverting forest lands for other purposes. The recovery of an ecosystem with respect to its health, integrity, and sustainability is evident from an initiative of planting (500 saplings of 49 native species) in a degraded landscape (dominated by invasive species) of two hectares in the early 1990s at the Indian Institute of Science campus (Ramachandra et al., 2016),and the region has now transformed into a mini forest with numerous benefits such as improvements in groundwater at 3-6 m (compared to 30-40 m in 1990), moderated microclimate (with lower temperature) and numerous fauna (including four families of Slender Loris). While confirming the linkages of hydrology, ecology, and biodiversity, the experiment advocates the need for integrated watershed approaches based on sound ecological and engineering protocols to sustain water and ensure adequate water for all. A well-known and successful model of integrated wetlands ecosystem (Secondary treatment plant integrated with constructed wetlands and algae pond) at Jakkur Lake in Bangalore (Ramachandra et al., 2018) provides insights into the optimal treatment of wastewater and mitigation of pollution. Complete removal of nutrients and chemical contaminants happens when partially treated sewage (secondary treated) passes through constructed wetlands and algae pond (sedimentation pond), undergoes bio-physical and chemical processes. The water in the lake is almost potable with minimal nutrients and microbial counts. This model has been functioning successfully f

ZHANG Xiaoju, REN Dawei

For highly built-up urban areas,further improving the waterlogging prevention and control standards and refining the waterlogging prevention and control system with a limited land use space are problems demanding prompt investigation.Taking Shenzhen's improvement strategies for waterlogging prevention and control standards as an example,this paper analyzed the main points and applicability of several measures,including source optimization,vertical adjustment,improvement of pipe network standards,multi-aspect drainage system,diversified detention measures,and joint control of flood and waterlogging.By investigating representative basins,this paper also built a Mike Flood model to evaluate the effects of different waterlogging prevention and control schemes.The results show that an 85% reduction of waterlogging risk areas can be achieved by comprehensively applying the waterlogging prevention and control measures according to local conditions under a once-in-a-hundred-year rainstorm,indicating the efficacy of those measures.The results provide a reference for cities to develop improvement strategies for waterlogging prevention and control standards under similar conditions.

ZHENG Defeng, ZHAN Shiyao, CAO Yongqiang

The spatiotemporal dynamic characteristics of regional potential evapotranspiration can lay a theoretical foundation for regional rational crop planting and scientific agricultural irrigation.In the context of global warming and increasing evapotranspiration rates,the Penman-Monteith equation is used to calculate the potential evapotranspiration (ET₀) and water budget (K) of Hebei Province from1967 to 2019 according to the actual meteorological observation data of twelve weather stations in Hebei Province,and the characteristics of their spatiotemporal dynamic variations are analyzed.On this basis,the analysis method of the Morlet wavelet function is introduced for the cycle analysis of ET₀ and K in 53 years.The results show that ET₀ has obvious zonal characteristics,and it is generally on the rise while K is on the decline during this period.Moreover,the evapotranspiration variations vary with seasons:ET₀ shows an upward trend in spring,autumn,and winter but a downward trend in summer.The cycle of K has the most significant oscillation at 35 a,and the scope of the oscillation is prominent in summer and autumn.Therefore,obvious changes in seasonal characteristics of Hebei Province have a great impact on K.The results can provide a reliable theoretical basis for agricultural water-saving and planting structure adjustment in Hebei Province.

T. Kril

Since the beginning of hostilities in the Ukraine territory, there have been several cases of detonation of dams on reservoirs. These events affected the surrounding areas, leading to a flood of different degrees. One of the significant cases occurred on the dam covering the Irpin river, close to Kyiv. It was built during the Kyiv Reservoir filling to prevent the flooding of the river valley and serves as a bridge. After a part of the dam was broken, water from the Reservoir began to fill the Irpin river. The flood threatened Demidiv and settlements further along the river valley. The study aims to determine the areas and volumes affected by water from the Reservoir, estimated material losses and the development of dangerous engineering and geological processes using remote sensing data. The method of identifying water bodies and, in general, bodies with a certain degree of hydration (vegetation, rivers, lakes, moistened soils) based on many spectral images consists of the calculation of Normalized Differential Water Indices. The water index was calculated from the green and near-infrared bands of space images from the Landsat 8-9 mission in the period from February 24 to April 30. The volume of water that formed the flood was calculated. For this, a digital terrain model was built based on the ALOS PALSAR space image, where each pixel of GeoTiff contains the height value. The flooded area is 16.5 square kilometres per month. The deposits of the first and second on the floodplain terraces, composed of uneven-grained sands, were flooded. The development of engineering-geological processes and the engineering protection of settlements are analyzed. The most common threats are flooding and swamping, erosional and gravitational processes are not observed.

Xianqi Zhang, Tianyi Liang

1. Research background Water is the source of life, the key to production, and the basis of ecology. With the gradual construction of ecological civilization, water ecology, and water environment have been paid more attention. China’s rapid development in recent decades is at the cost of environmental damage and over-exploitation of resources, including over-exploitation and pollution of water resources. Due to China’s large population and rapid industrial and technological development, China has a huge demand for water, therefore, under these prerequisites and backgrounds, water conservation has become an important goal. It is urgent to construct a water-saving evaluation system to evaluate the current water-saving status and put forward suggestions on the future direction and key points of water-saving. 1.1. Research progress Scholars at home and abroad have done research on the water-saving evaluation system. In 1959, the former China National Construction Commission proposed the city’s water-saving slogan for the first time. New water-saving ideas were put forward by General Secretary Xi in 2014 at the Fifth Meeting of the Central Financial and Economic Leading Group. During this time, in 1989, Zhu made quantitative evaluations of industrial water-saving levels in 18 cities in North China. Xu and Shan [1] made a brief introduction to water-saving agriculture and its physiological and ecological basis. Kang et al. [2] conducted research on water-saving irrigation in farmland. Feng [3–5] summarized and considered the current water-saving work in China. Chen et al. [6] explained the connotation of 203 X. Zhang, T. Liang / Desalination and Water Treatment 213 (2021) 202–213 water-saving society and conducted a preliminary study on the index system of water-saving society. Liu [7] researched and explained the water-saving evaluation of large-scale irrigation areas. Li [8] established an urban watersaving evaluation system based on the most stringent water resources management methods. In the beginning, foreign water-saving evaluations considered economic costs, and then gradually transformed them into holistic ones [9]. For example, Israel’s drip irrigation technology, which mixes water and nutrients by the drip irrigation center, greatly improves the utilization of irrigation water. Horton first proposed a water quality evaluation index system in 1965, the Howden Water Quality Index. Renato and Fibeiro [10] applied neural networks to construct optimal irrigation schemes to achieve water-saving effects in 1998. Tsadilas and Vakalis [11] proposed a long-term model framework for river basin framework and regional development. These studies are aimed [12], to a certain point to water-saving evaluation models for cities, irrigation districts, watersheds, etc., do not take the environment into account in which the evaluation subjects are located. It should be noted that any subject exchanges material energy with the surrounding environment [13–15]. The interaction of water, the most basic substance of nature, with its surroundings should be considered. The scientific evaluation of water-saving management and capacity in a region is an important basis for formulating water-saving development management and policies. In recent years, the comprehensive evaluation of watersaving capacity has developed from qualitative evaluation to quantitative evaluation and from simple main indicators to build an evaluation system to multiple indicators to build a comprehensive evaluation system. Analytic hierarchy process, fuzzy comprehensive evaluation, factor analysis, gray correlation method, etc., have been applied to the comprehensive evaluation of water-saving among them, the analytic hierarchy process is based on the hierarchical structure model and the construction of the judgment matrix to find the eigenvalues to determine the weight of each index factor. The judgment matrix is dominated by the evaluation criteria, and the objectivity of the evaluation criteria is difficult to reflect. Fuzzy comprehensive evaluation needs to construct a complicated membership function for a more complicated water-saving capacity evaluation system. When the factor analysis method processes the normal standardization of indicators, information loss and feature extraction decline will occur. The gray correlation method is based on the results of the correlation and comparison of indicators for objective evaluation, but it cannot reflect the interaction between water-saving management and the objective environment. Technique for order preference by similarity to an ideal solution (TOPSIS) is a new method for solving multi-attribute decision-making problems proposed in recent years. The principle is to sort according to the closeness of the evaluation object to the ideal target. The good value and bad value in the actual sample can be introduced into the final result, which can well reflect the objectivity of each indicator. Therefore, the analytic hierarchy process (AHP) and TOPSIS are combined to construct a water-saving evaluation model, which avoids decision-making errors caused by the one-sidedness of single-factor decisionmaking and differences in human subjective understanding. This can make more scientific and comprehensive judgments, and provide guidance for reality. 1.2. Research purposes The research direction of this article is based on a macro perspective and a large area of human activity, including urban factors, irrigation area factors, and natural environment factors within this area. The main carrier of water conservation assessment is the city. The city and its surrounding water environment are inseparable, interacting, and interdependent. This article explains the concept of the water environment, analyzes the operating mechanism of the water environment to show the interaction between the city and the surrounding environment, and proposes a new concept of the water environment. Through, the coupling of AHP and TOPSIS method, an urban watersaving evaluation model is built for water-saving evaluation of the water environment of Henan Province in the past 10 y. Its water-saving status and future water-saving development trends and priorities are analyzed. 1.3. Water-saving analysis of urban operation The water cycle in nature forms precipitation through evaporation, surface water is then formed, which penetrates into the groundwater and replenishes it. At the same time, during non-rainfall periods, groundwater will replenish surface water. This is the operating mechanism of the water environment in nature. Due to the construction of urban asphalt pavement, and the existence of a large number of concrete buildings. As a result of this, its mechanism is different from the natural water environment operation mechanism. Firstly, urban surface water is dominated by urban water landscape (lakes and rivers in some cities), but water landscapes are generally less, and most water landscapes often have no other water supply except rainwater replenishment. This has caused most water landscapes to consider anti-seepage measures. This has mixed a lot of artificial measures and human factors. At the same time, due to the construction of asphalt pavements and a large number of concrete buildings, the soil surface is hardened, and the water cycle cannot be performed effectively. In normal urban water cycle, surface water (mainly refers to temporary surface water formed by rainfall) is drained underground through the urban pipe network. Therefore, it is often necessary to comprehensively consider the degree of urban pipe network construction and pipe network bearing capacity when a water-saving model is constructed. At the same time, urban operation cannot be separated from economic production, and industrial production. Both of them will consume a lot of water resources. In industrial production, it is measured by the water consumption per unit of output value. So in industrial production, it is often measured by the water consumption level of 10,000 yuan GDP (Gross Domestic Production) in industrial production. 2. Overview of Henan Province Henan Province spans the Yangtze River Basin, Huaihe River Basin, Yellow River Basin, and Haihe River Basin. X. Zhang, T. Liang / Desalination and Water Treatment 213 (2021) 202–213 204 Most of the rivers in the province originate from the mountain areas in the west, northwest, and southeast. There are 493 rivers with a basin area of more than 100 km2. The province’s average water resources totalled 40.5 billion m3, ranking 19th in China, and its per capita water resources were <420 m3. This is equivalent to one-fifth of China’s average. Henan Province is the only province in China that flows through four major river basins. It is also the largest province in China with a long history and has bred Chinese civilization. Currently, under the strategy of the rise of the Central Plains, the water environment in Henan Province is relatively complicated, and so it is particularly important to evaluate urban water conservation. 2.1. Evaluation index selection and system construction The index screening is conducted from the perspective of urban water conservation, including the urban area and the surrounding environment, fully reflecting the urban operation and ecological cycle and the interaction between them. The indicators should fully reflect the state of urban development and the state of the natural environment in a region. The indicators are selected from the aspects of the city’s economic development status, social progress, and surrounding environment status. In terms of urban operation, the selected indicators should reflect the city’s water-saving capacity and efficiency. This is done by selecting indicators from the perspectives of people’s lives, industrial and commercial production, and economic construction. At the same time, the policy of a region is also an indicator of water-saving capacity. In

L. Prasetyorini, E. Cahya, R. D. Lufira

The Poso I Hydropower Station is located on the Poso River, at the downstream section of the Poso Lake in Central Sulawesi Province. At the weir site, the catchment area is 1906.30 km2, and the structures are designed for a 50 year return period. Flood discharge is 1456.50 m3/s, with the mean annual release being 127.85 m3/s. The total supply water level is 510.50m, and the minimum operating level is 506.00 m. The model uses an undistorted model with a scale of 1 to 60. The barrage needs to be reviewed for failure factors that are likely to occur similar to those used in potential failures in the construction of dams in general. The study was considered in three conditions: empty barrage condition, average level, and flood level. With the piping calculation method, the barrage used Lane and Bligh method. While the calculation of barrage sliding stability used Finite Element Method with Plaxis 2D program simulation got the safety factor at the empty condition and flood level. It is caused by water pressure at flood level conditions that influence barrage stability. Safety factor value exceeded permits made. The Poso I Hydropower Station was safe.