Number Of Flood Events Research Articles

Estimating the daily flooding probability by the compound effect of rainfall and tides in an Amazonian metropolis

Belém, the capital of the state of Pará, host of the 30th UN Climate Change Conference (COP30), which is located in the Brazilian Amazon, suffers from flooding caused by rainfall and tides. The objective was to estimate the daily flooding probability in Belém based on the two assumptions, i.e., the compound effect of rainfall and tides and rainfall only. In this case, rainfalls were analysed considering intensity and duration. Thus, it was possible to evaluate the flooding probability for each assumption and propose technological solutions to reduce this probability. Rainfall and tide height data for the 2003 to 2021 period were used. The minimum level causing flooding was defined analysing the compound effect (rainfall + tide height). The effects of rainfall and tides were also separately analysed with the aim of isolating the entry of tides into city canals. The daily flooding probability was estimated based on the study of the a priori probability derived from the ratio between the number of flooding events and the number of possible floods. The results showed that certain areas of Belém-PA could be flooded with a minimum value of rainfall plus tide height is 640.4 mm, if the rainfall intensity reaches at least 30 mm/h. Regarding the rainfall duration, the minimum value of rainfall plus tide height is 1398 mm for flooding to occur if rainfall lasts at least two hours. The flooding events were validated by examining local newspaper reports and photographic records describing and capturing flooding, respectively. The highest daily flooding probability occurred during the wettest period in the city, from January to May. The daily flooding probability was greatly reduced when only rainfall was considered. Thus, if city canals encompass floodgate systems, flood damage could be reduced. A floodgate systems project would be an important COP30 legacy for Belém. This system could help reduce the losses suffered by the poorest populations in Belém, who live in floodplain areas.

Enhancing human resilience against climate change: Assessment of hydroclimatic extremes and sea level rise impacts on the Eastern Shore of Virginia, United States

Coastal regions face climate-induced threats that have likely increased over the past four decades. In this work, we quantify the future climate impacts on hydroclimatic extremes in the risk-prone, 15-m-above-sea-level Eastern Shore of Virginia (ESVA) region, utilizing the Sixth International Coupled Model Intercomparison Project (CMIP6) Assessment Report 6 (AR6) and General Circulation Models (GCMs). We incorporate historical data on demographics and disasters, land use land cover (LULC), Landsat imagery, and sea level rise (SLR) to better understand and highlight the correlation between hydroclimatic extremes and societal components in this region. The hydrological model Soil and Water Assessment Tool (SWAT), Standardized Precipitation Index (SPI), Normalized Difference Water Index (NDWI), and Interquartile Range (IQR) method have been used to evaluate the intensity and frequency of projected climate extremes, in which SLR projections under different greenhouse gas emission pathways are temporally and spatially quantified. Our findings include (1) a trend towards wetter conditions is found with an increase in the number of flood events and up to an 8.9 % rise in the severity of flood peaks compared to the 2003–2020 period; (2) current coastal high-risk regions, identified using historical data of natural disasters, demographics, and LULC, are projected to be more susceptible to future climate impacts; and (3) low-lying coastal towns and regions are identified as currently vulnerable to coastal and SLR-induced flooding and are projected to become even more susceptible by 2100. This is the first effort that provides a valuable scientific basis for anticipated shifts in future climate patterns, essential for natural hazard prevention in ESVA. It highlights the need for authorities and decision-makers to plan and implement adaptive strategies and sustainable policies for the ESVA region and other coastal areas across the United States.

ENVİRONMENTAL PROTECTİON AGAİNST THE EFFECTS OF CLİMATE CHANGE THE ROLE OF GIS İN İTS FORMATİON

The article provides information about climate changes, which have become one of the global problems, and their impact on the living world, which worries the world community more and more. Unstable weather conditions are felt not only in Azerbaijan but also in several countries of the world and create problems. Increasing attention to these problems is manifested in the holding of a number of international events, including scientific and practical conferences. According to the latest assessment report of the Intergovernmental Panel on Climate Change, the average temperature on Earth has increased by 0.8 degrees in the last 100 years. The increase in temperature is mainly due to anthropogenic factors. The basis of anthropogenic factors are gases that create a thermal effect: carbon, methane, nitrogen oxide, nitrogen 1 oxide and chlorine-fluorine compounds. Space observations of the last 100 years show that the intensity and frequency of storms and blizzards have increased. Hot winds, hurricanes, and precipitation have intensified. At the same time, the number of flood events has also increased. If the surface of the ocean used to heat up to a depth of 1000 meters, then the warming reaches up to a depth of 2000 meters; resulting in hot currents becoming even hotter. That is, the main factor in the increase of all these natural disasters is climate change.

Typhoon and flooding occurrences on Chongming Island, Changjiang Estuary, as revealed by a newly acquired sedimentary record

Typhoon-induced storms surges and river flooding events represent two types of natural disasters that affect a wide range, occurring with high frequency and causing serious societal losses. Due to the limited duration of instrumental records, there is an inadequate understanding of the patterns and mechanisms underlying the variations in typhoons and floods. The interpretation of sedimentary records aptly compensates for these deficiencies in terms of the temporal scale, becoming a crucial medium for extending the temporal span of typhoon and flood records. Previous studies in this field have primarily focused on the identification of single types of extreme events. The Changjiang Estuary, particularly Chongming Island, is significantly affected by both typhoons and river floods, making it an excellent area for synchronous comparative studies of these two types of extreme events. Based on the analysis of a core sample, ZP02, collected from Chongming Island, in terms of chronological, sedimentological, and geochemical characteristics, specific tracing fingerprints for event deposits from typhoon and flood events are established. Sediments from typhoon events generally exhibit erosive contact surfaces, coarser grain sizes, and a tendency to become finer upwards, often featuring layers mixed with coarse sand and shell fragments. In contrast, flood event deposits vary in grain size, either coarser or finer, with abrupt contact surfaces compared to normal sediment layers, and are predominantly brownish-yellow in color. The fingerprint tracing results indicate that the typhoon event layers are characterized by high values in principal component 2 (PC2) of the elements, Zr/Fe and Sr/Fe ratios, with low values in principal component 1 (PC1) the elements and Ti/Ca ratio. Flood event deposits are marked by high values in PC1 and Ti/Ca ratio, low values in PC2 and Sr/Fe ratio, and an increase in Zr/Fe ratio in coarser flood layers but no significant change in finer layers. Based on these fingerprints, 19 layers of typhoon and the same number of flood events were identified in core ZP02, which correspond well with documentary records. The establishment of tracing fingerprints for typhoon and flood event deposits provides methodological support for the identification and interpretation of various extreme event deposits.

Regression Modelling of Flood Episodes in Ogbaru, Anambra State

Flooding has caused numerous damages to lives and properties. Ogbaru local government is a riverine area that was adversely affected by flooding due to the storm surges that over-flooded the riverbanks during the flooding incidents that affected most areas in Anambra State in the past. Thus, the aim of this study is to develop a regression model for flood events in Ogbaru Wetland, Anambra State. To achieve this, data was collected from the Nigerian Meteorological Agency's synoptic station (NIMET) for temperature, rainfall, relative humidity and the number of major flood episodes in the area for a40-year period (1971–2010). Multiple Linear Regression was used to analyse the data. The results obtained showed the values for Multiple R, R2, adjusted R2, standard error as 0.115618399, 0.013367614, -0.068851751, 1.836772885, 0.115618399, respectively. The correlation results presented relative humidity and rainfall as 0.757133219; number of flood events and rainfall as 0.107747581; number of flood events and relative humidity as 0.085395873. ANOVA used to determine the strength of the regression. Conclusively, it was observed that flooding in the area was caused by a combination of atmospheric variables that contributed roughly 1.34 percent. Also, anthropogenic and environmental variables were responsible for 98.66% of wetland flooding.

Machine learning techniques for flood forecasting

ABSTRACT Climate change resulted in dramatic change in the monsoon precipitation rates in Malaysia, contributing to repetitive flooding events. This research examines different substantial practicalities of machine learning (ML) in performing high-performance and accurate FF. The case study was The Dungun River. IGISMAPs datasets of water level and rainfall were investigated (1986–2000). The Forecasting was implemented for current (1986–2000) and near future (2020–2030). ML algorithms were Logistic Regression, K-Nearest neighbors, Support Vector Classifier, Naive Bayes, Decision tree, Random Forest, and Artificial Neural Network. Simulations were run in the Colab software tool. The results revealed that between 1986 and 2000, there would be an average of (18–55) floods around the Dungun River Basin. Floods occurred rarely before 1985. They have been common since 2000. 35 floods occurred annually on average since 2000. It is predicted that between 2020 and 2030, flooding events would grow on the Dungun River Basin. Most floods occurred due to rainfall between 1 and 500 mm. The maximum frequency of flooding was measured at 110 occurrences at a rainfall of 250 mm. The overall accuracies were 75.61%/ random forest, 73.17%/ KNN, and logistic regression/ 48.78%. Overall, the ANN models had a competitive mean accuracy of 90.85%.

Floods and Land Use Land Cover Changes in the Kalu River Basin: A Call to Action


 
 
 Floods are one of the most common natural disasters worldwide. Apart from rainfall, Land Use Land Cover (LULC) changes too are a main contributory factor for floods. This study attempted to understand the link between floods and LULC changes in Kalu river basin, which is the second largest river basin and an area that experiences recurrent floods in Sri Lanka. We studied peak water levels, number of flood events, changes in land use types and impacts in rapidly urbanizing two districts, Rathnapura (upper basin) and Kalutara (lower basin) during 2001-2020. The satellite images (LANDSAT) were obtained for 2001, 2009, 2015 and 2020 and land use classification was done using ArcGIS and Remote Sensing Tools. Main land use types and their transformations were investigated and ground-truthing was carried out. Accordingly, the main types of land uses identified were Natural Vegetation and forests (NV), Settlements (ST- housing and industrial lands), Cultivated Lands (CL), Water Bodies (WB) and Bare Lands (BL). The results indicated that the most drastic change was found in the natural areas (NV) and they have diminished while the lands with anthropogenic impacts (ST, CL and BL) have increased across years. The NV had occupied the highest land area in 2001 (42.4%) and has reduced by 14.2% by 2020. The ST and CL have increased by 8.6 % and 5.2% respectively. The monthly rainfall of Rathnapura and Kalutara (Source: Department of Meteorology, Sri Lanka) has increased with time, which is a main reason for the increasing peak water levels of these areas (Source: Department of Irrigation, Sri Lanka). However, a significant correlation also exists between the change of the settlement area with the peak river water levels in the lower basin (p=0.03, R2=99%; regression analysis). Rathnapura has experienced 3 major floods (floods above the high water alert level) from 2001-2020, while 16 major floods have occurred in Kalutara. During the major flood in 2017, the number of child deaths in Rathnapura was 14 while in Kalutara it was 24. Accordingly, the LULC changes of the whole basin along with rainfall seem to influence on the severity of floods in Kalutara more, as it is located in the lowest elevation level. When natural lands are transformed to anthropogenic- impacted areas with disturbances to the water cycle, increased impervious surfaces, reduced water storage capacities and loss of natural drainage, the flood risk tends to increase. Proactive approaches including proper land use planning and rainwater storage are urgently needed as the climate change too would trigger more floods. Thus, the flood mitigatory actions, especially, in the lower river basin should be a priority to ensure resilience and sustainability.
 Keywords: Kalu river basin, Land Use Land Cover (LULC) changes, Floods
 
 

Multi time scale influence of dams on bedload transport

Dams are ones of the main sources of anthropogenic disturbance to the ecology and geomorphology of rivers. The aim of the present study is to understand the mechanisms underlying their influence on downstream bedload transport in three gravel-bed rivers in the Morvan massif, France. The hydrological disturbance caused by four dams is examined at a short (2.4–2.7 years) and longer (21–28 year) time scale. At the short time scale, bedload displacement was monitored (RFID) at 8 study sites around the dams. Morpho-sedimentary characterization of the bed substrate was performed at the study sites and combined with analyses of the long profile evolution and the current cross profile.The flood regime has been to a varying extent durably reduced by the dams depending on their size and purpose: the mean annual maximum flood was reduced by 9 to 40% and the number of flood events by 27 to 73.5% over the 21–28 years period. Sediment availability and loose structures were found above the dams and below medium-sized dams (<10 m) with a null or moderate influence on the flood regime (configuration I). Sediment deficit, consolidated structures, bed coarsening and vegetation encroachment were observed within 20 km downstream of large dams (>15 m) influencing strongly or moderately the flood regime (configuration II). These morpho-sedimentary features significantly affect the current bedload dynamics, creating conditions more or less favorable for the mobility of the present and incoming bedload. The cumulative mean bedload distances of RFID tracers in configuration II are significantly lower (6.8–45 m) than in configuration I (78–315 m). The current flow management of the dams has only a moderate effect on the bedload distances recorded, as shown by the mean virtual bedload velocities, which confirm the different dynamics (0.42–0.91 m/d, and 0.62–6.44 m/d, for II and I respectively). Our results demonstrate how modifications of dams on flow and bedload discharge altered the downstream morphology, but also that this inherited morphology may now be the main controlling factor of bedload transport. These findings invite further discussion about the most appropriate ways to restore rivers downstream of dams when dealing with multi-decadal inherited morphological features.

Climate Change Flood Risk Analysis: Application of Dynamical Downscaling and Hydrological Modeling

Floods are a recurring natural phenomenon during the rainy season in many Brazilian municipalities. Nevertheless, shifts in weather patterns have contributed to an increased incidence of these events in urban areas, where their impact can be amplified by the way the surrounding catchment is occupied. Hence, the present study sought to evaluate the susceptibility of the urban drainage infrastructure in João Monlevade, Brazil, to the effects of climate change by undertaking a comprehensive assessment of the Carneirinhos catchment, including its morphometric characteristics. For this purpose, we employed a hydrological model driven by regional rainfall projections from a high-resolution climate model (HadGEM2-ES downscaled to 5 km resolution) under the Representative Concentration Pathways (RCP8.5) scenario. Several combinations of rainfall occurrence were simulated, incorporating temporal aspects (different durations and return times), as well as spatial aspects (concentrated and distributed rainfall within the catchment). The results showed that the area of exposed soil in the Carneirinhos catchment experienced an increase of more than 140% from 2016 to 2019, favoring runoff surface and evaporation, which contributed to the increase in the number of flood events in the region. In addition, only 1 of the 56 heavy rainfall event simulations performed did not exceed the capacity of the macro drainage gallery.

Spatiotemporal variations of riverine flood fatalities: 70 years global to regional perspective

AbstractFloods are among the most devastating natural hazards worldwide. While rainfall is the primary trigger of floods, human activities and climate change can exacerbate the impacts of floods and lead to more significant economic and social consequences. In this research, fluvial flood fatalities in the 1951–2020 period have been studied, analyzing the information reported in the Emergency Database (EM‐DAT). The EM‐DAT data were classified into five categories in terms of the number of events and fatalities connected with riverine floods, considering only events that caused more than 10 fatalities. The results show that the severity of flood‐related fatalities is not equally distributed worldwide, but presents specific geographical patterns. The flood fatality coefficient, which represents the ratio between the total number of fatalities and the number of flood events, calculated for different countries, identified that the Southern, Eastern, and South‐Eastern regions of Asia have the deadliest floods in the world. The number of flood events has been increasing since 1951 and peaked in 2007, following a relative decline since then. Though, the resulting fatalities do not follow a statistically significant trend. An analysis of the number of flood events in different decades shows that the 2001–2010 decade saw the highest number of events, which corresponds to the largest precipitation anomaly in the world. The lethality of riverine floods decreased over time, from 412 per flood in 1951–1960 to 67 in the 2011–2020 decade. This declining trend is probably a consequence of a more resilient environment and better risk reduction strategies. Based on the presented data and using regression analysis, relationships between flood fatalities and the number of flood events with population density and gross domestic product are developed and discussed.

Monitoring and forecasting the condition of structures in the small river basins in southern Russia

Introduction. The southern regions of Russia need to adapt to higher peak river flows and flash floods. Since 1960, the number of recorded flood events has increased. The intensity and severity of flood events tend to decrease, but their annual frequency is increasing. This illustrates the social component of flooding. Trends in the number of flood events are closely related to the increasing population in river valleys. “Integrated management” of construction sites in river basins is based on three elements: monitoring, forecasting and early warning, vulnerability assessment, mitigation and response. The purpose of this study is to establish means of prediction, risk assessment of operational construction projects in river basins taking into account the current natural and climatic factors.&#x0D; &#x0D; Materials and methods. The research is based on the factual material collected in the field studies in the river basins of recreational regions of southern Russia. Design, construction and operational documentation of complex structures was analyzed and their structural elements were evaluated.&#x0D; &#x0D; Results. On the basis of the carried out theoretical, field and numerical researches, the problem of increasing ecological safety of the urban environment was solved by monitoring, assessing, ranging of the technical condition of building structures and forecasting risks in the urbanized areas of river basins. The results of the research should be considered as a basis of practical methods for the complex estimation of ecological safety of natural and technical system of river basins. Further development of the topic can be connected with the scaling studies of urbanized territories, monitoring crisis sites and forecasting of the further condition of construction projects by subjects.&#x0D; &#x0D; Conclusions. The developed software package has practical importance, the product is implemented in the Republic of Crimea, in the operation of the long-term operated HES complexes of the Partizanskoe reservoir supplying water to the city of federal importance Simferopol and the Alminsky reservoir irrigating Bakhchisaray region of the peninsula and it is also being tested in the Krasnodar Territory, the Republic of Dagestan, the Stavropol Territory and Caucasian Mineral Waters.

Hubungan Pengetahuan dan Sikap dengan Kesiapsiagaan Masyarakat Menghadapi Bencana Banjir di Desa Brangkal Sragen

A flood is a natural phenomenon related to human behavior that occurs due to the accumulation of various factors. Generally, floods are caused by high rainfall which causes waterways to be unable to accommodate so that they overflow. The number of flood events in Central Java in 2018 was 82 times and in 2019 102 times. Based on the BPBD of Sragen Regency in 2018, 14 sub-districts in Sragen experienced flooding. The purpose of this study was to determine the relationship between knowledge and attitudes towards community preparedness to face flood disasters in Brangkal Village. This research is quantitative with the method of Cross-Sectional. The sampling technique in research with the method of cluster sampling of as many as 60 respondents according to the criteria of inclusion and exclusion. The research instrument used a questionnaire. Data analysis in this study was univariate and bivariate using the test Chi-Squared. The results showed that there was a relationship between knowledge (ρ value 0.000 &lt;0.05) and attitude (ρ value 0.001 &lt;0.05) with community preparedness in facing flood disasters in Brangkal Village, Sragen. This study concludes that there is a relationship between knowledge and attitudes with community preparedness to face flood disasters in Brangkal Village. This research is expected to add insight and increase public awareness about disasters to improve community preparedness, especially floods.

The tale of three floods: From extreme events and cascades of highs to anthropogenic floods

Right after a devastating multi-year drought, a number of flood events with unprecedented spatial extent hit different parts of Iran over the 2-week period of March 17th to April 1st, 2019, causing a human disaster and substantial loss of assets and infrastructure across urban and rural areas. Here, we investigate natural (e.g., rainfall, snow accumulation/melt, soil moisture) and anthropogenic drivers (e.g., deforestation, urbanization, and management practices) of these events using a range of ground-based data and satellite observations. These drivers can range from exceptionally extreme rainfall intensities, to cascades of several extreme and moderate events, and various anthropogenic interventions that exacerbated flooding. Our results reveal strong compounding impacts of natural drivers and anthropogenic triggers in escalating flood risks to unprecedented levels. We argue that a new form of floods, i.e. anthropogenic floods, is becoming more common and should be recognized during the “Anthropocene”. This specific form of floods refers to high to extreme streamflow/runoff events that are primarily caused, or largely exacerbated, by anthropogenic drivers. We demonstrate how the growing risk of anthropogenic floods can be assessed using a wide range of climatic and non-climatic satellite and in-situ data.

Flood Hazard and Risk Mapping by Applying an Explainable Machine Learning Framework Using Satellite Imagery and GIS Data

Flooding is one of the most destructive natural phenomena that happen worldwide, leading to the damage of property and infrastructure or even the loss of lives. The escalation in the intensity and number of flooding events as a result of the combination of climate change and anthropogenic factors motivates the need to adopt real-time solutions for mapping flood hazards and risks. In this study, a methodological framework is proposed that enables the assessment of flood hazard and risk levels of severity dynamically by fusing optical remote sensing (Sentinel-1) and GIS-based data from the region of the Trieste, Monfalcone and Muggia Municipalities. Explainable machine learning techniques were utilised, aiming to interpret the results for the assessment of flood hazard. The flood inventory was randomly divided into 70%, used for training, and 30%, employed for testing. Various combinations of the models were evaluated for the assessment of flood hazard. The results revealed that the Random Forest model achieved the highest F1-score (approx. 0.99), among others utilised for generating flood hazard maps. Furthermore, the estimation of the flood risk was achieved by a combination of a rule-based approach to estimate the exposure and vulnerability with the dynamic assessment of flood hazard.

Evaluation of Low-Cost Moisture Meters for Wood

Abstract Wood moisture meters are needed for a variety of purposes, including home inspections, assessment of water damage, evaluation of firewood, do-it-yourself (DIY) projects, and many more. With an increasing number of flood events, moisture-induced damage to the built environment will become more common. Monitoring of moisture in wood is one of the most important factors in damage assessment and control and thus, aid and guidance for the selection process of a meter is needed. Resistance and dielectric meters are commonly used to estimate the moisture content of wood products. They have become inexpensive and widely available to the public. This study tested the precision and accuracy of eight low-cost handheld moisture meters and compared them to three industrial-grade moisture meters. A general observation of this study is that moisture meters below $50 generally perform well. Differences in accuracy were found among meters. It was observed that meters come with different features, such as a custom density selector and visual elements to enhance the metering experience. These features were not taken into account for the evaluation, since they are difficult to objectively judge.

Flood Impact Assessment on Road Network and Healthcare Access at the example of Jakarta, Indonesia

Abstract. Climate change leads to an increasing number of flood events that poses threats to a large share of the global population. In addition to direct effects, flooding leads to indirect effect due to damages of the road infrastructure that might limit accessibility of health sites. For disaster preparedness it is important to know how flood events impact accessibility in that respect. We analyzed this at the example of the capital of Indonesia, Jakarta based on the flood event of 2013. The analysis was based on information about the road network and health sites from OpenStreetMap. We assessed impacts of the flood event by comparing centrality indicators of the road network as well as by an accessibility analysis of health sites before and during the event. The flooded areas were home to 2.75 million inhabitants and hosted 79 clinics and hospitals. The flood split the road network into several subgraphs. The city center maintained its importance for time-efficient routing as well as for easily accessible healthcare but might be prone to traffic congestion after such an event. Indirect effects via interrupted road traffic through flooded areas affected around 1.5 million inhabitants and led to an increase of travel time to the nearest hospital by five minutes based on normal traffic conditions.

Spatial-temporal trends analysis of flood events in the Republic of Armenia in the context of climate change

Abstract The primary goal of the study is to analyze the spatial-temporal trends and distribution of flood events in the context of climate change in Armenia. For that purpose, some meteorological parameters, physical-geographical factors and the flood events data were studied for the 1994–2019 period. The linear trends demonstrate an increasing tendency of air temperature and precipitation. Those trends expressed increased flood occurrences, especially for the 2000s, whereas the Mann–Kendall (MK) trend test reveals no significant change. The number of flood events reaches its maximum in 2011 with its peak in May. Out of 191 flood events, half of the occurrences are recorded in the flat areas and southern aspects of the mountains (22% of the country's territory). There is a certain clustering of flood events in the areas with up to 5° slopes (66% of flood events). The most flood vulnerable areas were analyzed and mapped via Geographical Information System (GIS). The GIS-based mapping shows the location of flood vulnerable areas in the central, northern parts of the country, and the coastal areas of Lake Sevan. Our methodological approach elaborates the localization of flood-prone sites. It can be used for the flood hazard assessment mapping and risk management.

Implications of land use transitions and climate change on local flooding in urban areas: An assessment of 42 Indian cities

Urban development induced land transitions affect urban hydrology, resulting in increased flooding risks. Climate change-related precipitation changes are an added complexity to the flood risks of cities. This study examines the role of land use changes in determining the occurrence of urban flooding events across 42 Indian cities under current and future climate change scenarios. Landsat images for 1990, 2000, 2010, and 2017 have been processed using a hybrid classification technique to determine the land use shares for all cities. A typical event-count study using newspaper archives has been conducted to create a flooding event database. A multilevel model employing logistic mixed-effects approach was used. Future projections of the occurrence of flooding events for nine models under three climate change-related Representative Concentration Pathways (RCPs)—2.6, 4.5, and 8.5—and three urban development scenarios have been carried out. The results suggest that cities should preserve the land uses that act as a sponge—the green, open and blue spaces. As these spaces decrease, the projected flooding events increase. Under the RCP 2.6 scenario, the number of flooding events is significantly lower (95 % confidence) than under RCPs 4.5 and 8.5. The expected flooding occurrences between RCP4.5 and RCP8.5 are not significantly different (95 % confidence) for many scenarios, suggesting that Indian cities should aim for a world temperature increase of below 2 °C, or devastating consequences are imminent. This study highlights the need for Indian cities to undertake integrated spatial planning measures for a resilient, sustainable urban future.

Profiling a possible rapid extinction event in a long-lived species

Infectious disease is a contributing factor to species extinction or endangerment. Extinction is most likely to occur when a pathogen is evolutionarily novel, or when it utilizes an alternate reservoir, or when hosts have small pre-epidemic populations. Here we focus on such a case where a mystery disease almost drove the range restricted, Bellinger River Snapping Turtle (Myuchelys georgesi), in north-eastern NSW, Australia, to extinction in less than a month. The disease did not affect other turtle species, and the juvenile population of M. georgesi appears unaffected. The cause of the disease remains unknown, but may be a novel virus and whether the species can recover with or without human intervention is currently unknown. Here, we review the biology of M. georgesi and explore the epidemiology of the disease. We highlight circumstantial evidence of the potential role of recent environmental change in the susceptibility of M. georgesi. We show that long-term regional warming and localised drying reduced both water levels in the river and the number of flooding events that occurred prior to the disease outbreak. We also provide evidence that the food web may have been disrupted, possibly causing malnutrition and reduced immunocompetence of sub-adult and adult turtles. We hypothesize that these factors may have exacerbated the virulence and contagiousness of a novel, but as-yet unidentified pathogen, and must be also mitigated in any future recovery actions. The identity of the pathogen is necessary for managing the recovery of the species, however, understanding the processes that rendered the species susceptible to infection is of equal importance for planning the recovery of the species from the brink of extinction.

Experimental floods: A new era for Spanish and Mediterranean rivers?

The provision of human-designed floods in regulated rivers is still an incipient worldwide practice. However, these floods have already been shown to have relevant effects on the ecogeomorphic integrity of rivers altered by flow regulation. In Spain, experimental floods were legally established in 2008 and were stipulated in two subsequent Basin Management Plans as compulsory practice for improving the functioning of strategic river reaches. Since that time, a number of flooding events have been carried out in rivers of Mediterranean condition. This paper reviews the main consequences of experimental flood releases in three Spanish river sites downstream of major hydraulic infrastructures. In each case, the ecologic and geomorphic effects of the releases are analysed in parallel with their causes and consequences, thereby providing a detailed understanding of the dynamics of each scenario. The Spanish examples and the lessons learned from them are contrasted with examples of experimental floods from other countries (U.S.A., Switzerland, Australia). Lastly, recommendations are proposed to improve the implementation of future experimental floods in Spain and other Mediterranean countries.