Hydrometeorological Hazards Research Articles

An Index for Snowmelt-Induced Landslide Prediction for Zavoj Lake, Serbia

In February 1963, a huge landslide (ca. 1,950,000 m3) blocked the Visočica River and, thus, formed Zavoj Lake. The primary objective of this research was to investigate the importance of snowmelt in relation to landslide occurrence and to define the critical climatic conditions that may trigger massive winter landslides. We used monthly precipitation and average monthly maximum temperature data from meteorological and precipitation stations in the Visočica River basin (Dojkinci) and in the immediate proximity of Lake Zavoj (Pirot, Dimitrovgrad and Topli Do) as data inputs to the Snow-Melt Landslide (SML) index. It considers the summed monthly precipitation for previous months that continuously have an average maximum temperature below 0 °C. According to this method, the event at Zavoj Lake stands out among all other precipitation and snowmelt values for the past 72 years. After applying the SML index, all stations showed values of >300 mm for February 1963, which we consider as the threshold value for potential landslides appearance. In addition to meteorological data, we applied the SML index to data from the Coordinated Regional Downscaling Experiment (CORDEX) regional climate model outputs for the region from 2022 to 2100. As expected, climate change will have influenced the temperature values, especially during the winter. Conversely, the study area is experiencing drastic changes in land use caused by depopulation, leading to a reduced risk of winter landslides in the Visočica basin. We suggest that future climatic conditions in the area will make it more likely to experience extreme summer precipitation events, which might trigger large landslides. The SML method can be implemented for all landscapes that experience snowy winters, providing information in a timely manner so that local residents can react properly when the probability of landslide occurrence rises. The SML index, grounded in essential meteorological principles, provides a tailor-made, data-driven methodology applicable across varied geographical settings. Its utility extends to mitigating hydro-meteorological hazards on scales ranging from local to national scales, offering diverse and effective early warning solutions.

Cloud-to-Ground Lightning in Cities: Seasonal Variability and Influential Factors

AbstractUrban-induced land use changes have a significant impact on local weather patterns, leading to increased hydro-meteorological hazards in cities. Despite substantial threats posed to humans, understanding atmospheric hazards related to urbanisation, such as thunderstorms, lightning, and convective precipitation, remains unclear. This study aims to analyse seasonal variability of cloud-to-ground (CG) lightning in the five large metropolitans in Bangladesh utilising six years (2015–2020) of Global Lightning Detection Network (popularly known as GLD360) data. It also investigates factors influencing CG strokes. The analysis revealed substantial seasonal fluctuations in CG strokes, with a noticeable increase in lightning activity during the pre-monsoon months from upwind to metropolitan areas across the five cities. Both season and location appear to impact the diurnal variability of CG strokes in these urban centres. Bivariate regression analysis indicated that precipitation and particulate matter (PM) significantly influence lightning generation, whilst population density, urban size, and mean surface temperature have negligible effects. A sensitivity test employing a random forest (RF) model underscored the pivotal role of PM in CG strokes in four of the five cities assessed, highlighting the enduring impact of extreme pollution on lightning activity. Despite low causalities from CG lightning, the risk of property damage remains high in urban environments. This study provides valuable insights for shaping public policies in Bangladesh, a globally recognised climate hotspot.

Mapping cumulative compound hydrometeorological and marine-induced risks on the NW Mediterranean coast

Coastal risks in the Mediterranean are a result of the complex interplay between hydrometeorological and marine hazards. The region encompasses areas with varying degrees of vulnerability to these hazards, as well as spatial variations in exposure values, making it essential to adopt a comprehensive and nuanced approach to risk assessment and management. It is worth noting that hydrometeorological hazards, such as flash floods, can often have a greater impact than strictly coastal hazards, highlighting the need to consider the full range of potential risks. Therefore, coastal managers must adopt a multi-hazard approach to make sound risk management decisions. This study addresses this need using an index-based framework that assesses the integrated risk in time and space (hereafter referred to as cumulative compound risk) in coastal zones by aggregating the main hydrometeorological and marine hazards, the vulnerability of the territory to both types of hazards, and values at exposure. The framework is designed for use at large spatial scales (applied to a 1100 km coastline in this study), with the basic spatial unit being relevant for management (here set as the municipality in this study). Its application enables the assessment of spatial variations in integrated risk as well as individual hydrometeorological and marine contributions. The combined use of the indices and cluster analysis helps identify similarities and differences in the risk profile of spatial units, and thus, define homogeneous areas from a risk management perspective. In this study, the framework was applied to the Spanish Mediterranean coastline, an area representative of the climatic, geomorphological, and socioeconomic conditions of the Mediterranean coast.

Road bridges exposure and alternative routes: towards the definition of road network resilience

The road network represents both element-at-risk and key infrastructure to ensure the accessibility of peripheral areas. The overall risk levels of bridges depend on geophysical (mainly earthquakes and landslides) and hydrometeorological hazards (mainly floods), the physical vulnerability of structures, and the exposure (mainly resulting from traffic flows and the presence of alternative roads). In mountain contexts and peripheral territories, the accessibility of entire territorial system directly depends on few trunk and secondary roads. The risk assessment of bridges, according to the Ministerial Guidelines, provides inputs for a territorial risk assessment starting from the accessibility of peripheral territories and the redundancy of the road network as features to determine the resilience of the road network. This study aims at understanding the relationships between bridges as elements-at-risk part of the road network and the influence they have on the overall accessibility of a territory. In this study, through a GIS analysis of a set of selected roads of the Provinces of Caserta (Campania Region), the presence of bridges along the selected roads have been combined with data on the accessibility levels of municipalities they connect. At this purpose, reference to the classification provided by the National Strategy for Inner Areas (SNAI) has been made to understand how such a classification can change due to a road interruption because of a bridge interruption. The contribution aims at setting the stage for the implementation of a method to determine the presence of alternative roads based on travel times adopted by the SNAI classification and, as a result, the definition of unique threshold values that justifies the variation of the exposure class and allows to determine the resilience of the whole road network.

Implementing close-range remote surveys for the digitally supported rock mass stability analysis

A digitally supported rock mass stability analysis is herein presented for the implementation of non-contact close-range remote surveys against landslide hazard in sheltered environments, such as Marine Protected Areas. An airborne photogrammetric survey was carried out at the Lachea Islet (Sicily), which is part of a small volcanic archipelago with a peculiar geological history, hosting unstable rock masses belonging to the first eruptive stages of Mount Etna. The digital model built for this study allowed extracting the discontinuity orientation data, performing a kinematic analysis along the recognized discontinuity clusters, and quantifying the volume of potentially unstable boulders. Laboratory tests allowed achieving the main physical-mechanical parameters of involved rocks, which were used to perform a quantitative stability analysis under both deterministic and probabilistic approaches, based on the extracted digital data. Finally, a 3D rockfall trajectory analysis was carried out by simulating statistical rockfall path on the digital model built for the study. Results highlighted a poor stability in the studied islet sector, which is worsened by taking into account the high seismicity that characterizes the area. The main tourist elements of the islet must be considered at risk, as they are located within the simulated trajectories of the landslides. The methodological protocol carried out for this study, based on conventional procedures but using remotely derived and digitally processed information, can be considered a useful tool in the frame of nature-based solutions for hydro-meteorological hazards connected to climatic changes.

Reducing hydro-meteorological risks through nature-based solutions: A comprehensive review of enabling policy frameworks in the European Union

The international community, particularly across the European Union (EU), is increasingly recognizing and promoting Nature-based Solutions (NBS) as long-term and sustainable measures against hydro-meteorological hazards such as flooding, coastal erosion, heat waves and landslides. Yet, scaled implementation of NBS at EU and global level presently remains a challenge due to often complex and lengthy permitting procedures. While efforts have been made to highlight the explicit and implicit role of NBS in major global and European policy frameworks, uncertainty remains when it comes to the level of coherence across government levels, from international to national and local scale. This paper attempts to address this gap by introducing an open-access online policy catalogue pertaining to the implementation of 740 NBS projects globally to mitigate the impact of hydro-meteorological phenomena. Based on a policy screening of 88 NBS projects in Europe and an in-depth analysis of the NBS permitting paths across seven Open-Air Laboratories in European countries, we examine the linkages between European and national legislation and policies. Understanding these linkages will help promote NBS mainstreaming as the NBS agenda is set at EU and global level while implementation is heavily dependent on national-scale governance. We identify a common permitting path for NBS paved by the EU in several directives, as well as some divergence in the implementation of these directives at national level which can pose significant challenges to the uptake of NBS. The NBS policy catalogue provides a valuable resource for further analysis of the NBS policy context from local to global levels towards increasing uptake and acceptance of NBS in Europe and beyond.

Integrated assessment of flood and drought hazards for current and future climate in a tributary of the Mekong river basin

Abstract Projecting floods and droughts characteristics under climate change is important to formulate an integrative management plan and enhance resiliency of society. However, studies that provide the integration of floods-drought hazards are scarce within literature. This study assessed flood and drought hazards separately and together for future climate in the Mun River basin, a tributary of the Mekong river. A non-modelling and multi-variate approach was used to assess flood and drought hazard respectively. Climate model ensemble suggests that the area under ‘high’ and ‘very high’ drought hazard level will increase from 27% and 4% during baseline period (1981–2010) to 43% and 37%, respectively, during near-future period (2021–2050). Similarly, an increase in ‘high’ and ‘very high’ flood hazard from 11% and 22% during baseline period to 16% and 24% during near-future period is projected. When both hazards are considered together, the total hazard is projected to increase by 155% in the near-future period. 76% of the catchment during the near future period will have combined hazard level from ‘medium’ to ‘very high’ compared to the 30% during the baseline period. The research presents a grim outlook on for the basin, with the area at risk from both hydro-meteorological hazards.

For the Record: Second Thoughts on Early Warning, Early Action (EWEA), EW4All, or EWEA4All?

Over the past four decades, people around the globe have experienced unprecedented escalations in the frequency, intensity, magnitude, and location of anomalous hydrometeorological (hydromet) hazards attributed in large measure to the direct and indirect effects of global climate-change-related variability and extremes. The WMO, impelled by an unabated warming of the global climate system and its related extremely anomalous hydromet impacts, chose in March 2022 “Early Warning, Early Action” (EWEA) as the theme for its World Meteorology Day. The theme was praised in a press release by UN Secretary-General Antonio Guterres, who called for the development of a new EWEA initiative to ensure that “every person on Earth is protected by early warning systems within five years”. By mid-2022, several meetings and workshops had already been held by the WMO to forge the new initiative on its road to the UN Climate Conference of Parties (COP27) in November in Sharm El Sheikh, Egypt. COP27 provided a suitably prominent venue for launching the new USD 3.1 billion, 5-year EWEA initiative; there, Secretary-General Guterres formally tasked the WMO, in partnership with the UNDRR, to lead it. But COP27 proved to be interesting as well as illuminating in other, less publicized ways having to do with EWEA. There, what had been the working title of the new initiative was officially changed to EW4A, “Early Warning for All”. Despite the seemingly perfunctory nature of this change, the reality is that it will almost certainly have outsized impacts on the strengths, weaknesses, opportunities, and constraints (SWOC) met specifically in planning and implementing the new initiative’s “early action” strategies and tactics. It is particularly important to bear in mind that, as things now stand, various unanticipated challenges having to do with the lack of organizational experience and capacity with regard to “early action” are likely to arise with the WMO-led implementation of the new initiative. Considering the new EW4A acronym as if it was a commercial brand can, like this, be instructive in thinking about how the seemingly perfunctory name change—from EWEA to EW4A—will impact the initiative’s implementation of “early action”. Doing so can be instructive because, just as the logos of companies like Apple, Nike, or Starbucks eventually became the face of their respective products, so too have branded acronyms like NASA, IOC, WHO, and INTERPOL become the face of their governmental institutions’ or global initiatives’ respective commissions and commitments. It follows then that if “consumer” interest is to be taken seriously and is (hopefully) long-lasting, then the branding of a new product or initiative must be undertaken with great consideration before a final identifier—be it a logo, a catchphrase, or an acronym—is selected. The question in the case of the new WMO-led initiative, then, is the following: Was this issue seriously taken into consideration before EWEA was so abruptly replaced by EW4A at COP27 in Egypt in November 2022? This pointed question is especially meant to highlight how the continued use of the original EWEA acronym by way of developing regional EWEA centers under the “Early Warning for All” umbrella has the possibility of turning regional potential energy into kinetic energy which will be essential if the theoretical gains of future “early warning” (EW) forecasting science are to be effectively translated into “early action” (EA) strategies and tactics that actually, finally, protect people and property across the entirety of the earth from the impending severe impacts of our changing climate future. Thus does this paper raise valid concerns about the balance between support and funding for EW and EA.

The Disaster Protection System of Mountainous Rivers in Japan: The Example of the Akatani Watershed’s Reconstruction

On 5–6 July 2017, an unstable atmospheric condition caused an unusual concentration of rainfall above the Northern part of Kyushu Island, triggering a set of hydro-meteorological hazards. Within the affected area, the mountainous subwatershed of the Akatani River was significantly impacted by numerous landslides combined with debris flow and floods. National and local agencies deployed a plan of reconstruction to restore the floodplain and protect inhabitants. Regarding the hydrosystem in the Akatani watershed, this reconstruction project mainly focuses on the restoration of damaged protection systems and the construction of new infrastructures. Thus, this paper aims to explain the restoration plan of the Akatani River in terms of the strategic Japanese River System Sabo and then as a model of a national-scale spatial plan. It draws on (i) a literature review based on the historical evolution of Japanese protection systems and the River Sabo System; (ii) field surveys in 2019, 2022 and 2023, in conjunction with (iii) interviews with local, regional, and national officials; and (iv) a Geographical Information System analysis of previously and newly built protection systems through aerial photograph interpretation and geospatial data. Sabo works implemented in the Akatani watershed illustrate the engineering vision of Japanese river management. They also constitute a comprehensive system and include a downstream–upstream logic which echoes that of the River System Sabo. In addition, the disaster of July 2017 and the government’s response emphasize the continuous adaptation and improvement of the Japanese disaster management system, which mitigates severe disasters.

Gap between impact-based and impact forecast and warning: Implications for people-centric early warning system (EWS) in India

This paper explores the scope and potential of Impact-based Forecast and Warning (IbFW) services for hydro-meteorological hazards in India. It builds upon several global and national initiatives which emphasize that the Early Warning System (EWS) requires to be people-centric and inclusive in order to reduce disaster risk. The objectives of the study are: to understand the current Impact-based Forecast and Warnings framework of the India Meteorological Department (IMD) and its usefulness from the people's perspective. Drawing from fieldwork conducted in Krushnaparasad Block, Puri District of India, the paper argues that there is a shifting focus towards meeting the requirements of general public, but there is a long way to go as far as meeting expectations are concerned. It calls for changes such as strengthening risk assessment modeling, clarity over institutional mandates and adoption of flexible governance frameworks to move from an Impact-based paradigm to Impact Forecast and Warning services.

Extreme precipitation over complex terrain using multiple remote sensing observation: A case study in the Great Bandung, Indonesia

Intense precipitation events are the main cause triggering hydrometeorological hazards over complex terrain. Two extreme precipitation (EP) events led to major flooding on 23–25 March 2021 and produced a rain-hail mixture (RHM) on 11 April 2021 in the Greater Bandung (GB) basin area, Indonesia. We investigated the spatial and vertical structure of precipitating cloud systems and the plausible mechanism triggering the two case studies with combined multiple remote sensing observations using an X-band polarimetric Doppler Weather Radar (Xpol) and X-band rain scanner radar (RSR) network, supported by rain gauges and satellite observation. The local processes controlling the intense rainfall events over the complex topography were quantified for the first time using an observational campaign in Indonesia. During the first EP event (23–25 March 2021), the modified satellite algorithm successively confirmed that the mesoscale convective system triggered the local anomalous circulation. The RSR network reveals that the EP in eastern GB contributed to the overflow of the Citarum River alongside the basin, coinciding with the eastward propagating convective system that produced oblate-shaped water droplets without hail. Nevertheless, during the second EP event on 11 April 2021, the strengthening of mountain-based convection played a main role in producing RHM, confirmed by a hail differential reflectivity larger than 12 dB and exhibited hail early stage over two height levels in different locations (981 m and 1033 m) in the GB. Our study also found Doppler vorticity-based and rain sizes combination indicators using RSR data networks in capturing such extreme weather events over complex topography with 35 min early times to support the early warning system of hydrometeorological disaster mitigation over GB, Indonesia.

HYDRO-METEOROLOGICAL ANALYSIS OF EXTREME WEATHER IN INDONESIA USING COUPLED ATMOSPHERIC-HYDROLOGICAL MODEL

In recent years, hydro-meteorological hazard in the area involving coastlines has been dominated the disaster occurrence in Indonesia. In the last 10 years, the combination of the extreme weather and the environmental capacity degradation result in more flooding vulnerability. In 11-17 January 2021, heavy flood affected South Kalimantan, Indonesia, with causing many casualties. The flood characteristics was similar with the extreme flood in Jakarta in the preceding year in 2020, and more extreme floods occurred in the following year in 2022. Our goal is to analyze the extreme weather from the hydro-meteorological perspective and identify the key factor behind the high impact flood in South Kalimantan. Two factors, sea surface temperature (SST) and soil moisture (SM) content were highlighted and the sensitivity analysis was performed to identify their influence to the flood response at the time of the event. The coupled atmospheric model of Weather Research and Forecasting (WRF) and the hydrological model extension (WRF-Hydro) will be used to reconstruct the flood event.

The Impact of Flooding on the Community: A Case of Gweta and Zoroga Villages, Botswana

Floods continue to cause devastating impacts on society, the economy, and the environment. In Botswana, the semi-arid climate makes the country more vulnerable to the effects of hydro-meteorological hazards. The villages of Gweta and Zoroga, located in the Central Tutume district in northeast Botswana have been experiencing flood events almost yearly during the rainy season, with the 2016/2017 being the most severe. The aim of this study was to assess the socio-economic impacts of these floods in the two villages and to map areas susceptible to flooding. A semi-structured questionnaire and a key informant guide were used to collect data from the heads of households. Participatory Geographical Information System was used to map areas vulnerable to flooding. The causes of flooding were increased rainfall intensities, coupled with a lack of flood control structures along the Maun-Nata highway. The devastating 2016/2017 floods caused damage to houses and other property and losses amounting to BWP18 482.58 (1US$=13.24 BWP) worth of cattle, BWP11 282.84 worth of goats and BWP1 314.22 worth of chicken

Index-based tools for livelihood security and resilience assessment (LiSeRA) in lower Mekong Basin

This paper presents a framework and toolkit for assessment of multi-hazard livelihood security and resilience in the Lower Mekong Basin (LMB) communities. The LMB is a subsidiary region of the Mekong region in South East Asia, and is frequently exposed to hydrometeorological hazards and anthropogenic stressors that expose and directly affect the livelihoods of more than sixty-five million people living in the region. The main purpose of the study is to support decision-making and risk management planning through integration of the concepts of livelihood security and resilience into a holistic framework, and subsequently developing an index-based toolkit for conducting assessments. Firstly, dimensions, sub-dimensions and indicators for measurement of livelihood security and resilience in the LMB were identified through comprehensive literature review and expert consultation. Then, several local workshops were conducted with various stakeholders (researchers, government officials, community people) in the LMB region to validate the indicators and generate weightages. The indicators were then arranged in a matriculated form, and the weightages were used to generate the algorithm for computing the quantitative outputs of livelihood security and resilience in study area. An Excel toolkit and a ‘R’ programming package were developed using the algorithm for visualization of the assessment outcomes. The proposed framework and toolkit are expected to assist researchers, government officials and development professionals in generating robust resilience assessment indices for risk informed decision-making and planning.Brief outline of the method•Livelihood security and resilience concepts were integrated to generate a holistic assessment framework and an indicator library.•Weightages for indicators were generated using the Analytical Hierarchical Process (AHP) through consultation with relevant stakeholders.•The indicator library was developed into an algorithm-based Excel and ‘R’ programming toolkit that provides quantitative assessment outputs.

Modelling Water Erosion and Mass Movements (Wet) by Using GIS-Based Multi-Hazard Susceptibility Assessment Approaches: A Case Study—Kratovska Reka Catchment (North Macedonia)

Kratovska Reka is a short (17.3 km) left tributary of Kriva Reka, whose watershed (68.5 km2) is located on the northwestern slopes of the Osogovo Mountains (North Macedonia). Due to the favorable natural conditions and anthropogenic factors, the Kratovska Reka catchment is under a high risk of natural hazards, especially water erosion and landslide occurrences. For this reason, the paper presents an approach of modelling of potential erosion and areas susceptible to the above-mentioned hydro-meteorological hazards in the Kratovska River catchment. Firstly, this study analyzed the main geographical features that contribute to intensive erosion processes in the area. Then, using the Gavrilović EPM erosion potential method, an average value of 0.56 was obtained for the erosion coefficient Z, indicating areas prone to high erosion risk. Furthermore, by using landslide susceptibility analysis (LSA), terrains susceptible to landslides were identified. The results shows that 1/3 of the catchment is very susceptible to mass movements in wet conditions (landslides). According to the combined multi-hazard model, 3.13% of the total area of the Kratovska River catchment is both at high risk of landslides and under severe erosion. The Kratovska River catchment is significantly endangered by the excessive water erosion processes (39.86%), especially on the steep valley sides, i.e., terrains that are completely exposed, under sparse vegetation, and open to the effects of distribution/concentration of the rainfall amounts throughout the year. Identifying locations with the highest erosion risk serves as the initial step in defining and implementing appropriate mitigation measures across local and regional scales, thus enhancing overall resilience to environmental challenges.

Flood risk assessment through rapid urbanization LULC change with destruction of urban green infrastructures based on NASA Landsat time series data: A case of study Kuala Lumpur between 1990–2021

Kuala Lumpur, as one of the fastest growing cities in the world, is facing significant negative impacts on its urban ecosystem services (UESs) due to rapid urbanization. Among the classes of land use and land cover (LULC) in Kuala Lumpur, urban green infrastructure (UGI) plays a crucial role in mitigating these impacts. The present study aimed to evaluate the amount of UGIs in Kuala Lumpur for a better understanding of hydro-meteorological hazards assessment. To this end, historical data from 1990 to 2021 were collected using NASA Landsat 4 and Landsat 8 to evaluate the past and current tendencies of LULC in Kuala Lumpur. Various techniques and software, including Markov Chain, ArcGIS, and TerrSet, were utilized to examine the interactions and interpret and create maps. Six categories of land were defined, including grass, waterbodies, soil, buildings, urban forest trees, and urban trees. The study utilized Landsat's Normalized Difference Vegetation Index (NDVI) to analyze the impact of modifications on UGIs. Additionally, the Landsat Normalized Difference Water Index (NDWI) was employed to illustrate changes in urban water values. The findings revealed a significant decline in urban forest trees from 15.99% in 1990 to 6.5% in 2021, resulting in an increase in urban water values and an increase in flooding. The NDWI values in 1990 ranged between 0.383635 and −0.593184, while by 2021, they had fallen to between 0.593288 and −0.44379. These changes in NDVI and NDWI have contributed significantly to the intensity and frequency of urban flooding in Kuala Lumpur.

Analysis of Madden-Julian Oscillation (MJO) on extreme rainfall event in the west coastal south Sulawesi for mitigation disaster

Madden Julian Oscillation (MJO) is one of the global phenomena that affects weather and climate conditions in Indonesia. MJO increases the rainfall rate and causes a plethora of extreme rainfall occurrences in areas along its trajectory. Those extreme rainfall events could trigger hydrometeorological hazards that endanger the surrounding environment. As the first step to analyse this extreme weather event, this research tries to determine the threshold of the extreme rainfall rate. The method used for determining the threshold is the statistical method 98th percentile. The next step is to identify the frequency trend of the extreme rainfall in the period of 1991 to 2020, by measuring the rainfall rate and comparing it with the normal value. If the rainfall rate is above the normal condition in a certain threshold, then it is considered an extreme rainfall event. After that, these extreme rainfall occurrences are compared to the active MJO phase to find out the influence of MJO to the rainfall in the west coast of South Sulawesi. Then, the dynamical atmospheric conditions are to be analysed during those extreme rainfall events. The result shows that the frequency trend of extreme rainfall events are generally negative in 5 (five) regions, which means an insignificant correlation between MJO and rainfall rate. In contrast, 3 (three) other regions show a positive trend. The influence of an active MJO on the extreme rainfall rate is about 34,1%. Meanwhile, the rest for about 65,9% is influenced by other factors. The use of MJO indices for generating early warning hydrometeorological disasters is by utilising the MJO monitoring data, supported with the analysis of dynamical atmospheric condition in the west coast of South Sulawesi.

Progress toward resilient and sustainable water management in the Vietnamese Mekong Delta

AbstractSinking and shrinking, the Vietnamese Mekong Delta is a materialization of dynamic river flows, sediment flows, and coastline processes. Past policy aspirations and extensive water infrastructures have shaped the delta into one the most significant food producing landscapes in Southeast Asia. Yet, these changes have also created new environmental risks by transforming the hydrological system. Research has produced a growing and increasingly diverse empirical literature on the delta's environmental context, without necessarily providing water resource managers, policymakers and practitioners with the information needed to galvanize more resilient development. This focus review presents a detailed overview of the recent scientific findings, exploring how the management of water resources is changing, as well as their inter‐relationship with land use, policy, socio‐economic transitions, and global environmental crises. Compound and systemic risks to the delta include climate change, hydrometeorological hazards, upstream developments and an unsustainable development trajectory. We outline scientific knowledge gaps, as well as the pressing need for sharable analysis‐ready data and innovations. Finally, we provide recommended future research avenues for multiscale actions toward a sustainable and resilient delta future.This article is categorized under: Human Water > Water Governance Science of Water > Water Extremes Science of Water > Water and Environmental Change

Real time control of nature-based solutions: Towards Smart Solutions and Digital Twins in Rangsit Area, Thailand

The intensity and frequency of hydro-meteorological hazards have increased due to fast-growing urbanisation activities and climate change. Hybrid approaches that combine grey infrastructure and Nature-Based Solutions (NBSs) have been applied as an adaptive and resilient strategy to cope with climate change uncertainties and incorporate other co-benefits. This research aims to investigate the feasibility of Real Time Control (RTC) for NBS operation in order to reduce flooding and improve their effectiveness. The study area is the irrigation and drainage system of the Rangsit Area in Thailand. The results show that during the normal flood events, the RTC system effectively reduces water level at the Western Raphiphat Canal Station compared to the system without RTC or with additional storage. Moreover, the RTC system facilitates achieving the required minimum volume and increasing the volume in the retentions. These findings highlight the potential of using RTC to improve the irrigation and drainage system operation as well as NBS implementation to reduce flooding. The RTC system can also assists in equitable water distribution between Klongs and retention areas, while also increasing the water storage in the retention areas. This additional water storage can be utilized for agricultural purposes, providing further benefits. These results represent an essential starting point for the development of Smart Solutions and Digital Twins in utilizing Real-Time Control for flood reduction and water allocation in the Rangsit Area in Thailand.

An impact-based forecast system developed for hydrometeorological hazards

This article describes the Impact-Based Forecast (IBF) system developed for hydrometeorological disasters in Brazil. The system was conceived on some fundamental elements: mapping risk areas for floods and mass movement events, characteristics of the vulnerability and population exposed in such areas, and implementation of a robust observational network. Data from all warnings issued between 2017 and 2021 are compared with disasters recorded during the same period. The results show the efficiency of such a system when the warning level is very high, but also the weaknesses at moderate warning levels. The system, developed for a country with a very large number of risk areas and a high level of social vulnerability of the population living in these areas, can be adapted and implemented in other countries with such similarities.