• Energy Research

The hydrological conditions upstream of the Ciliwung watershed are changing due to climate and land-use changes. Any changes in this area may increase the flood frequencies which may have countless consequences downstream of the watershed where the Jakarta city is located. We simulated the effects of land-use and climate changes on flooding (e.g., peak flow and river discharge) in the upper Ciliwung River basin in Greater Jakarta, Indonesia. Hydrologic Modeling System (HEC-HMS), a rainfall-runoff simulation model, was used to simulate peak river discharge values for current and future conditions. The model was calibrated and validated based on the observed river discharge data from February 2007 and January 1996, respectively. The statistical analysis showed that the performance of the model is satisfactory, with Nash–Sutcliffe efficiency 0.64 and 0.58 for calibration and validation, respectively. The coefficients of determination values are 0.86 and 0.82, respectively. The effect of the projected land-use changes alone in 2030 increased the peak flow by approximately 20%. When considering the land-use changes in conjunction with the future climate scenario, the peak flow based on the precipitation corresponding to a 50-year return period in 2030 increased by 130%. Based on the results of this study, it is urgent that a flood management plan be implemented in the target area to reduce flooding in the near future.

Abstract The water budget in the Vietnamese Mekong Delta (VMD) depends heavily on rainfall which play crucial roles in supporting agriculture, aquaculture, and local livelihoods. This study evaluated rainfall trends across the VMD from 1978 to 2022, revealing significant spatial and seasonal variations. While a few inland stations showed marginal increases in dry season rainfall, our findings indicate an overall decline in both wet and dry season rainfall across the region. This trend is particularly concerning for coastal areas, such as Ca Mau Province, which rely predominantly on rainfall due to limited upstream inflows; these areas recorded substantial declines in annual and wet season rainfall, with Sen’s slope values of –7.582 mm/year and –6.335 mm/year, respectively. Although the VMD is situated within the Asian monsoon region, geographical factors, including coastal and inland locations, exert a strong influence on rainfall variability patterns across the delta. The observed rainfall decline has critical implications for water resource management in the VMD, where climate variability is projected to increase. Although other factors, such as evapotranspiration and land use changes, also impact water availability, our study focuses on rainfall’s direct role. These findings highlight the necessity for adaptive water management strategies that account for declining rainfall, particularly in vulnerable coastal areas. This study provides a critical analysis of rainfall trends in the VMD to inform adaptive water resource strategies under climate variability, answering how these long-term trends affect the region’s water availability and resilience, and contributes to the broader understanding of climate change impacts, informing both regional adaptation strategies and global climate policy formulation.

This study examines the changing rainfall patterns in the Vietnamese Mekong Delta (VMD) utilizing observational data spanning from 1978 to 2022. We employ the Mann–Kendall test, the sequential Mann–Kendall test, and innovative trend analysis to investigate trends in annual, wet, and dry season rainfall, as well as daily rainfall events. Our results show significant spatial variations. Ca Mau, a coastal province, consistently showed higher mean annual and seasonal rainfall compared to the further inland stations of Can Tho and Moc Hoa. Interestingly, Ca Mau experienced a notable decrease in annual rainfall. Conversely, Can Tho, showed an overall decrease in some months of the wet season and an increase in dry season rainfall. Furthermore, Moc Hoa showed an increase in the number of rainy days, especially during the dry season. Principal component analysis (PCA) further revealed strong correlations between annual rainfall and extreme weather events, particularly for Ca Mau, emphasizing the complex interplay of geographic and climatic factors within the region. Our findings offer insights for policymakers and planners, thus aiding the development of targeted interventions to manage water resources and prepare for changing climate conditions.

The design, development, and operation of current and future urban water infrastructure in many parts of the world increasingly rely on and apply the principles of sustainable development. However, this approach suffers from a lack of the necessary knowledge, skills, and practice of how sustainable development can be attained and promoted in a given city. This paper presents the framework of an integrated systems approach analysis that deals with the abovementioned issues. The “Water and Urban Initiative” project, which was implemented by the United Nations University’s Institute for the Advanced Study of Sustainability, focused on urban water and wastewater systems, floods, and their related health risk assessment, and the economics of water quality improvements. A team of researchers has investigated issues confronting cities in the developing countries of Southeast Asia, in relation to sustainable urban water management in the face of such ongoing changes as rapid population growth, economic development, and climate change; they have also run future scenarios and proposed policy recommendations for decision-makers in selected countries in Southeast Asia. The results, lessons, and practical recommendations of this project could contribute to the ongoing policy debates and decision-making processes in these countries.

As the backbone of Vietnam's economy, the country has recently established a number of policies for promoting and investing in smart agriculture in the Mekong Delta, the country's largest agricultural hub, to foster overall socio-economic development. However, water remains a critical constraint for crop production, with progress being hindered by water scarcity and quality issues, and compounded by socio-economic transformation and climate change. Considering these challenges, this study used the CROPWAT model and a wide spectrum of climate change scenarios to investigate future total water demands in the 2030s and 2050s as well as drought levels in two underdeveloped semi-mountainous reservoir catchments, i.e., O Ta Soc and O Tuk Sa in An Giang province. The results suggest that the usable storage capacity of the O Ta Soc reservoir will increase to 650,000 m3 to meet water supply demands under all climate change scenarios and the medium-term, moderate drought conditions. The useable storage capacity of the O Tuk Sa reservoir will also be increased to 880,000 m3 and the irrigation area would see a marked 70% reduction compared to its design irrigation. Under these circumstances, the O Tuk Sa reservoir will continue to supply water under all climate change scenarios and medium-term droughts. As a core element for strategic planning and to ensure efficient management of water resources, the results highlight the importance of estimating potential runoff and rainfall in semi-mountainous reservoir catchments under various drought conditions in order to propose the suitable expansion of the useable water storage capacities.

The construction of large-scale infrastructure projects like dams can substantially alter local hydrological systems, prompting concerns about their impacts on river water levels and discharge. This study was undertaken in response to the compelling need to investigate and analyze the potential implications of water scarcity, particularly within the framework of the Bisalpur Dam located on the Banas River. This study uses non-parametric trend analysis tests - Mann-Kendall (MK) and Modified Mann-Kendall (MMK) for river discharge and water level trend analysis, and Sen's Slope and Pettit's test for detecting changes or trends. Significant shifts in these parameters were identified post-construction. From 1960 to 2011, the Dam's construction led to a marked decrease in peak discharge (MK/MMK statistics Zc = −3.24; Pc = 0.001), with a Sen's slope of −21.51 MCM/year. Before the Dam's construction, the peak discharge reached a maximum of 7680 MCM in 1981–82. The gauge station's water level significantly decreased (MK/MMK statistics Zc = −3.46; Pc = 0.001) at an annual rate of −0.035 m/year. This level, peaking at 201.59 m in 1981–82, declined from an average of 196.04 m–194.5 m post-construction. The findings underscore the extensive impact of dam construction on local hydrological parameters. These results hold significant implications for future infrastructure projects, emphasizing the critical need for comprehensive environmental impact assessments to be conducted before project implementation. This understanding can aid in designing interventions with reduced environmental impacts, leading to more sustainable infrastructure development.

AbstractClimate change and anthropogenic factors have exacerbated flood risks in many regions across the globe, including the Himalayan foothill region in India. The Jia Bharali River basin, situated in this vulnerable area, frequently experiences high-magnitude floods, causing significant damage to the environment and local communities. Developing accurate and reliable flood susceptibility models is crucial for effective flood prevention, management, and adaptation strategies. In this study, we aimed to generate a comprehensive flood susceptibility zone model for the Jia Bharali catchment by integrating statistical methods with expert knowledge-based mathematical models. We applied four distinct models, including the Frequency Ratio model, Fuzzy Logic (FL) model, Multi-criteria Decision Making based Analytical Hierarchy Process model, and Fuzzy Analytical Hierarchy Process model, to evaluate the flood susceptibility of the basin. The results revealed that approximately one-third of the Jia Bharali basin area fell within moderate to very high flood-prone zones. In contrast, over 50% of the area was classified as low to very low flood-prone zones. The applied models demonstrated strong performance, with ROC-AUC scores exceeding 70% and MAE, MSE, and RMSE scores below 30%. FL and AHP were recommended for application among the models in areas with similar physiographic characteristics due to their exceptional performance and the training datasets. This study offers crucial insights for policymakers, regional administrative authorities, environmentalists, and engineers working in the Himalayan foothill region. By providing a robust flood susceptibility model, the research enhances flood prevention efforts and management, thereby serving as a vital climate change adaptation strategy for the Jia Bharali River basin and similar regions. The findings also have significant implications for disaster risk reduction and sustainable development in vulnerable areas, contributing to the global efforts towards achieving the United Nations' Sustainable Development Goals.

Agriculture in the Global South is innately susceptible to climatic variability and change. In many arid and semi-mountainous regions of the developing world, drought is regularly cited as a significant threat to agricultural systems. The objective of this study is to assess the impacts of climate change on drought and land use and land cover (LULC) change in a semi-mountainous region of the Vietnamese Mekong Delta. We assessed previous drought trends (1980–2020) and future drought in the context of climate change, in accordance with three selected scenarios from the Coupled Model Intercomparison Project Phase 6 global climate models which have recently been released by the Intergovernmental Panel on Climate Change (IPCC) (2021–2060) using the Standardized Precipitation Index (SPI). The change of land use for the period 2010–2020 was then assessed and the associated climatic variability explored. The results show that for the period 1980–2019, SPI 3 responds quickly to changes in precipitation, whereas SPI 9 showed a clear trend of precipitation over time. The first longest duration occurrence of drought for SPI 3, SPI 6, and SPI 9 patterns were respectively 15–16, 21, and 25 months at Chau Doc station, and respectively 11, 14–15, and 16–17 months at Tri Ton station. Future precipitation and both maximum/minimum temperatures are projected to increase in both the wet and dry seasons. In addition, for all-time series scales and climate change scenarios, the levels of drought were slight, followed by moderate. In the future, the humidity at Chau Doc station is expected to decrease, while the occurrence of drought events is expected to increase at Tri Ton station, particularly in SPI 6 patterns (110 drought events in 1980–2020, and up to 198 drought events in the future). Moreover, between 2010–2020, the agricultural land area was seen to decrease, replaced by non-agricultural land uses that were found to increase by 22.4%. Among the agricultural land area, forestry, rice crops, and upland rice were found to reduce by 7.5, 16.0, and 21.2%, respectively, while cash crops and perennial crops increased by 26.4% and 170.6%, respectively. Amongst other factors, it is concluded that the variability of climate has led to drought and thus impacted on the conversion of LULC in the study area. Due to low economic efficiency, changing climate conditions, and a lack of irrigated water, the area of rice crops, forestry, aquaculture, and upland rice decreased, replaced by land for orchards for fruit production and other cash crops.