Moderate Flood Research Articles

STUDI TINGKAT BAHAYA BANJIR DAS BATANG KURANJI KECAMATAN PAUH KOTA PADANG

High rainfall with human factor make happen change characteristic especially at upper zone cause batang Kuranji stream. This research was conducted with the aim of 1) determine the characteristics of land Batang Kuranji Pauh sub district 2) determine the level of flood hazard Batang Kuranji Pauh sub district 3) analyze the spatial distribution of flood hazard Watershed (DAS) Batang Kuranji Pauh sub district. The results showed that: 1) there are differences in the characteristics of the land (land form, slope of land, damming of river, river meanders, the average slope of the watershed, land use, rainfall, soil texture and soil permeability) of each area of research that could potentially trigger flooding, 2) High level of flood hazards present in the study area with the Land Force (a) F1.Qal.I.pm.Al, (b) F1.Qal.I.Sw.Al, (c) F1.Qal.III.Kc.Lat, (d) F2.Qf.I.Kc.Lat, (e) F2.Qf.I.Pm.Al, (f) F2.Qf.I.Pm.Lat, (g) F2.Qf.I.SwAl, (h) F2.Qf.III.Ht.And, (i) V1.QTau.III.Pm.Lat, (j) V1.QTauIII.Pm.Lat, The study area has a moderate flood level of hazard present in the study area with land units (a) V1.QTau.III.Ht.Lat, (b) V1.QTau.III.Pm.Al, (c) V1.QTau.III.H.And. 3) The area of research that has a high level with a broad floods 486.58 Ha. And a research area with moderate flood hazard level has an area of ​​998.391 Ha.

Detection of flash-flood potential areas using watershed characteristics: Application to Cau River watershed in Vietnam

The main purpose of this study is to detect flash-flood potential areas based on the pre-event characteristics in the study area. Five physical factors including slope, land use, soil texture, tree canopy density, and drainage density were used to create index maps in the Geographic Information System (GIS) environment. Each index was classified from 1 to 10 by identifying their influence levels with the presence or absence of flash floods based on the Flash Flood Potential Index (FFPI) model. As the result, the most susceptible areas were given a value of 10 and the least susceptible areas were given a value of 1. These indices were then mapped and integrated into a weighted linear model. Analytic Hierarchy Process (AHP) was used to determine the weighted correlation among elements based on their importance to this phenomenon. Weighted Flash Flood Potential Index (WFFPI) map was classified into four levels, including very high, high, moderate, and low flash flood potential. The result shows that more than 10% of the total area has the greater possibility to be affected by a high-intensity flood, and distributed at the north and northeast mountain ranges while most of the area is at a medium value with 84.35%. Finally, the similarity between results in this study and reference results from HEC-RAS model showed the reliability of the applied method.

Geomorphic response of a mountain gravel-bed river to an extreme flood in Aberdeenshire, Scotland

This study uses the 2015 ‘Storm Frank’ flood on the River Dee, Aberdeenshire, to assess the impact of extreme events on river dynamics. The Storm Frank flood (>200 year recurrence interval) caused significant local morphological change that was concentrated in the middle portion of the 140 km long river and overall net degradation that primarily occurred through lateral adjustment processes. Although the flood did not cause widespread change in channel planform, morphological change at the reach scale (<1 km) was significant. Bank scour resulted in channel expansion and lateral migration as well as widespread aggradation on existing gravel beds. The HEC-RAS and CAESAR–Lisflood models were used to determine the impact of morphological changes from the Storm Frank flood on a series of future hypothetical floods. The results show that inundation is highly influenced by the degree of morphological change for moderate floods, but not for high magnitude ones. In-channel scour and bank erosion can lead to an increase in channel capacity, thereby decreasing inundation. Conversely, where conveyance capacity is decreased by aggradation, flood risk inherently increases. The impact of these changes was great for a five-year return period flood, but minimal for a magnitude flood comparable to that of Storm Frank. Our modelling results also reveal that the inundation model is sensitive to the grain size and channel bed roughness input parameters, as these parameters impact flow discharge and flood hydraulics. Accurate determination of sediment parameters and degree of morphological change is therefore critical in flooding modelling and flood hazard management. Supplementary material : Peak discharge and rainfall during the 2015 Storm Frank storm, parameters used in the hydrological model CAESAR–Lisflood and sediment budget statistics of each DEM of difference threshold are available at: https://doi.org/10.6084/m9.figshare.c.4847946 Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/cc/SJG-early-career-research

Decadal and Episodic Changes in Morphology and Migration of the Confluence Bar of Two Alluvial Rivers in Louisiana, USA

AbstractPast research on fluvial dynamics at the confluence of two alluvial rivers has mainly focused on downstream flow structure and bed scoring, often using laboratory experiments and numerical modeling. Little is investigated about yearly and episodic dynamics of confluence mouth bars that can affect downstream morphology using field measurements. In this study, we analyzed the migration of a confluence mouth bar of two free meandering alluvial rivers, the Amite and Comite Rivers in coastal Louisiana, USA from 2002 to 2017. Remote sensing images were utilized to investigate the decade‐long morphologic changes. To assess episodic dynamics, we employed terrestrial laser scanning measurements to acquire high‐accuracy digital elevation models at the confluence before and after three floods in 2017. Our study found that the Amite‐Comite confluence mouth bar migrated downstream 55 m in the past 15 years, and its angle reduced by 55° from 100° to 45°. The fast migration was a result of sediment deposition and channel deformation around the confluence mainly during the years when the tributary‐to‐main channel discharge was lower (<0.25). The study further reveals that a single moderate flood could strongly affect the mouth bar, as shown by an increase of the projected surface area by 114% and an increase of volume of the confluence mouth bar by 68%.

Urban flood disaster risk evaluation based on ontology and Bayesian Network

Expected increases in intensity and frequency of rainfall extremes due to climate change, and increased paving and loss of water storage space in urban areas is making cities more vulnerable to pluvial flooding. It is a crucial step towards risk mitigation and adaptation planning to evaluate and predict flood disaster risk. In this study, a model coupling ontology and Bayesian Network that can capture the potential relationships between different factors influencing flood disaster and has capable of quantifying uncertainty and utilizing both data and observations was proposed. Based on the proposed model, the flood disaster risk in Zhengzhou City was assessed, which was validated by comparing with actual historical flood records. And the sensitivity analysis was carried out based on this model to determine that which factors would affect the disaster most. The results show that 72.3% of the study area was characterized by very-high to moderate flood disaster risk, which was mainly located in the central and eastern regions. The sensitivity analysis show that the rainfall duration is the most impactful factor, and the factors related to disaster-formative environment have low effect. The results revealed quite good agreement between the predicted flood disaster risk with actual flood records, which can be useful to assist flood mitigation and management. The model proposed in this study offers the Zhengzhou City and flood researches around the world, an effective way for evaluating flood disaster risk to manage uncertainty in water availability under climate change.

Chemical composition of Panicum maximum ‘BRS Zuri’ subjected to levels of salinity and irrigation depths

The study of cultivars with moderate flood tolerance is essential to their use in pastures irrigated with saline water. The aim of this study was to evaluate the chemical composition of Panicum maximum ‘BRS Zuri’ under the effect of different irrigation depths and levels of salinity. A randomised block design of split plots was used with five replications per treatment. The treatments resulted from the combination of three levels of water salinity (S1 = 0.6, S2 = 1.8 and S3 = 3.0 dS m-1) and four levels of irrigation (I1 = 60%, I2 = 80%, I3 = 100% and I4 = 120% of the evapotranspiration). The chemical composition of the grass, Panicum maximum ‘BRS Zuri’, cut at 28 days, was evaluated over two cycles. There was an interaction between the factors (salinity x irrigation depth x cycle) for the dry matter (DM) content. With the increase in irrigation depth, there was a linear reduction in the crude protein (CP) content in both cycles. The neutral detergent fibre (NDF) and cellulose (CEL) content increased linearly as a function of the irrigation depth, while the lignin (LIG) content decreased linearly with irrigation depth. It was concluded that high levels of salinity cause reductions in the dry matter content in response to increased water availability and extension of the cultivar cycles. The reduction in saline levels under low water availability results in a higher CP content. Salinity has a negative effect on the NDF, ADF, HEM, CEL and LIG content as the irrigation depth increases.

Effects of drought-flood abrupt alternation on phosphorus in summer maize farmland systems

Phosphorus (P) is well known as a vital nutrient required for plant growth and a critical factor often causing eutrophication in water bodies. However, few studies have focused on the effects of drought-flood abrupt alternation (DFAA), a new type of extreme climate event, on the transformation of P in farmland systems. In this study, we, therefore, focused on DFAA effects on available P (AP) in topsoil, soluble P (SP) and total P (TP) in surface runoff, as well as plant P contents and P uptake in summer maize farmland systems. Field control experiments (sheltered under a ventilated shed with an artificial rainfall device) were conducted to simulate two levels of DFAA (i.e., light drought-light flood and moderate drought-light flood) during parts of two summer maize growing seasons (i.e., seeding-jointing stage and tasseling-grain filling stage). Results showed that DFAA increased AP concentration in topsoil, which was probably induced by the accumulation of the phyla Proteobacteria and Actinobacteria under moderate drought and by an increase in phosphate-solubilizing bacteria (PSB), especially the genera Bacillus and Bradyrhizobium. In addition, broken soil aggregates and increasing soil porosity caused by DFAA could also cause an increase of AP in topsoil. Soluble P and TP in surface runoff showed a decreasing trend with moderate drought in DFAA. The higher AP increased the root P uptake, while P in stems and leaves could be transported to fruits under DFAA with moderate drought. The results could provide some references for the study of the effects and adaptation-strategies related to extreme climate events and their effects on P in farmland systems.

PREDICTION OF FLASH FLOOD SUSCEPTIBILITY USING FUZZY ANALYTICAL HIERARCHY PROCESS (FAHP) ALGORITHMS AND GIS: A STUDY CASE OF GUELMIM REGION IN SOUTHWESTERN OF MOROCCO

Abstract. In recent decades, many of the countries around the world as well as the south-western Morocco (Guelmim region, Assaka watershed), was subject to flood-storm causing huge human and material damages. The current study focuses on the Prediction of flash flood susceptibility using Fuzzy Analytical Hierarchy Process (FAHP) algorithms and Geographic Information System (GIS) technical. Flash floods areas were identified based on seven flash flood conditioning factors (Soil Moisture Index (SMI), Drainage Density, Rainfall, LULC, Altitude, Slope and Soil). Using AHP the weight derived for the factors were SMI 37% Rainfall 24.30%, Drainage Density 15.57%, LULC 9.98% Altitude 6.39% Slope of the river basin 4.06% and Soil type 2.70%. Then, applying a fuzzy inference system to create flash flood vulnerability maps. The resulting maps were classified into three categories: low, moderate and high flash flood susceptibility; indicated that the areas at the outlet of the watershed and which are close of the main affluent wadis (Seyyad and Oum Al-Achar) were very susceptible to flooding. This study will be helping these zones to be prioritized for the conservation and managing of flash floods.

Multi-criteria decision-making for the analysis of flash floods: A case study of Awlad Toq-Sherq, Southeast Sohag, Egypt

The multi-criteria method is a widely used technique to study and analyze the impact and causes of natural hazards. Our study area, that forms a part of the governorate of Sohag, lies in Southeast Sohag and is one of the most flash flood prone regions of Egypt's Eastern Desert. In the last decades, this area of Sohag has suffered from frequent flash floods, with some flood events resulting in human casualties. In our study, we use a multi-criteria process combined with geographical information system (GIS) and remotely sensed data to produce a flash flood susceptibility map. In addition, we discuss the various factors related to flash flooding such as elevation, slope, drainage network, lithology, topographic wetness index, as well as land use, and reclassify these based on their contribution and their effect on flood probability. To calculate the weighted factor for each raster, a pairwise matrix was constructed. Results from our multi-criteria analysis for flash flooding indicate that approximately 5% of the total study area is at a very high risk of flooding, 10% at a high risk, and 25% at a moderate flood risk. Furthermore, our results highlight the areas at risk of flooding and the need for the development of relevant warning systems. Our results also indicate that the southeastern part of the study area is most susceptible to flash floods and we suggest that the necessary focus be given to this region as well as the implementation of a flood warning system. A consistency index was used to determine the accuracy of our model and was calculated to be 0.058, indicating a well-performing model.

Flood-Prone Area Assessment Using GIS-Based Multi-Criteria Analysis: A Case Study in Davao Oriental, Philippines

Flooding is one of the major destructive natural disasters in Davao Oriental, Philippines, and results primarily from a high incidence of typhoons and heavy rainfalls. The main objective of this study was to identify flood-prone risk areas by mapping them based on the integration of multiple indicators, including rainfall, slope, elevation, drainage density, soil type, distance to the main channel and population density. For this purpose, a GIS-based flood risk spatial assessment was conducted by using analytic hierarchy process (AHP), weights by rank (WR) and ratio weighting (RW) frameworks to determine the relative importance of each indicator against another in the province of Davao Oriental. The resulting flood-prone areas by the three methods are validated by comparing with the estimated flood map based on ground truthing points from a field survey. The comparison results show that AHP is the most appropriate method among them to assess flood hazard. The result of the AHP flood risk map shows that 95.99% (5451.27 km2) of Davao Oriental is under low and moderate flood risk. The high and very high flood risk area covers approximately 3.39% (192.52 km2) of the province, primarily in the coastal areas. Thirty-one out of the one hundred eighty-three (31/183) barangays (towns) are at a high to very high risk of flooding at current climate, calling for the immediate attention of decision-makers to develop mitigation strategies for the future occurrence of flooding in Davao Oriental.

Combining deep flooding and slow-release urea to reduce ammonia emission from rice fields

Abstract The high risk of ammonia (NH3) emission from rice fields limits the efficient and cleaner production of rice (Oryza sativa L.). Currently, little is known about the combined effects of irrigation and fertilization on NH3 emission from rice fields. Specially, the contributions of different field factors to NH3 emission and the role of the rice canopy in NH3 emission are not fully understood. This study aimed to (i) determine the best combination of irrigation and fertilization for reducing NH3 emission from rice fields and (ii) elucidate the mechanisms involved based on the data from 17 field factors. A 2-year field experiment (2017 and 2018) was performed consisting of nine treatments: the full combination of three irrigation treatments (deep flooding (DF), moderate flooding (MF), and shallow flooding (SF)) and three fertilization treatments (the control test (N0), urea (U), and slow-release urea (SU)). The results indicated that nitrogen (N) application significantly increased NH3 emission from rice fields (p

Dynamic rule curves for multipurpose reservoir operation for different floods

Abstract Dynamic flood control rule curves (DFCRCs) that balance the use of conservation space between flood control and conservation purposes are usually necessary for the operation of a multipurpose reservoir. This paper therefore proposes a procedure to apply the DFCRCs of an historically-based actual flood for reservoir operation versus different floods whose hydrograph shapes vary widely. The proposal uses related-size characteristics (e.g. net retention of the DFCRCs and peak discharge of associated outflows) in a stepwise manner from those of the smallest return period to those of the largest one. Illustrative applications of the procedure to the operation of the multipurpose Ubol Ratana Dam (The Nam Pong Basin, Thailand) have indicated that it enables the DFCRCs to ensure the reservoir's operation against various floods. Its operational results for the large and moderate floods in 1990 and 1995 are comparable to those of historically based floods. In addition, impact assessment of climate change on the operational performance has shown that the system could not protect the areas upstream and downstream of the dam from the HadCM3A2 and HadCM3B2 floods at the 80th and 95th percentile levels during the future 2050s period.

Association between floods and hospital admissions for schizophrenia in Hefei, China: The lag effects of degrees of floods and time variation

BackgroundSchizophrenia is a serious mental disorder, endangering 7.5 million patients in China. Floods, as the adverse consequence of temperature-rise, have a negative influence on mental health. However, the relationship between floods and schizophrenia is still insufficient. This study aimed to quantitative the relationship between floods and the admissions for schizophrenia in Hefei, China. MethodsA Poisson generalized linear model (GLM) combining a distributed lag non-linear model (DLNM) was used to quantify the lag effects of floods on schizophrenia and subgroups (male, female; ≤40 y, >40 y; the married, the unmarried) from 2005 to 2014, Hefei, China. We further explored the effects of different degrees (moderate and severe) of floods and their temporal changes on schizophrenia. ResultsThere was a significant association between floods and admissions risk for schizophrenia. And the lag effects for schizophrenia lasted ten days (lag 5-lag 14), with the greatest effect on lag 9 (RR = 1.036, 95% confidence interval (CI): 1.014–1.058). The married, ≤40 y were sensitive to floods. The significant difference wasn't found for genders. The effects of the severe flood were higher than moderate floods, with the largest RR of 1.073 (95%CI: 1.029–1.119). The adverse effects were found in the middle and late period with a decreasing trend in the later period. ConclusionsThis study suggests a significant association between floods and schizophrenia with ten days of lag effects in Hefei, China. Male, female, <40 y and the married are vulnerable to both moderate and severe floods. The findings might be used to allocate medical resources of mental health after floods.

Reconstruction of sunspot activity, cold and warm events, and drought and flood events in the central plain of China during the northern Song Dynasty using historical documents

The Northern Song Dynasty was an important and prosperous dynasty in the history of China, and it existed during a period of climate abnormality. Climate change research for the Northern Song Dynasty era has significance for understanding the interaction between agricultural civilizations in the central plains and nomadic populations in northern China, transfer of the economic and cultural centers of China, and the vicissitudes of the Northern Song Dynasty. There is currently considerable disagreement regarding climate change in the Central Plain during the Northern Song Dynasty era. Many precious and valuable historical documents and records about the Northern Song Dynasty have been collected, and abundant records of sunspot activity, cold and warm weather, drought and flood events have been compiled. Using the Mann-Kendall test, wavelet analysis, R/S analysis, and frequency analysis etc. mathematical statistics methods, sunspot activity, cold and warm events, and drought and flood events were quantitatively reconstructed. There are 15 sunspot maximum years and 16 sunspot minimum years, the cycle length of sunspot activity is 8–14 years, and the average cycle length is 11 years. Hot years account for 11.3% of the total years; warm years account for 12.7%; cold years account for 20.7%; and freezing cold years account for 3.3%. Mann-Kendall test results show that cold and warm variations are natural fluctuations, and there is no indication of abrupt climate change during the Northern Song Dynasty. Morlet wavelet analysis indicates that there are weak high-frequency oscillations and short oscillation periods with three years before 1052 AD, and there are oscillation periods of six years and clear alternations between warmth and cold during 1060-1120 AD. R/S analysis indicates that the Hurst index (H) of cold and warm index series is 0.6155, and the fractal dimension (D) is 1.3845. Since 0.5 < H < 1 and 1 < D < 1.5, fractal structures are evident in the time series of cold and warm indexes, past increments are positively correlated with future increments, and the average cycle length in the time series for cold and warm indexes is 6 years. Temperatures first decreased rapidly followed by a slow increase with long-term fluctuations, and the mean temperature during the Northern Song Dynasty era is 0.4 °C higher than that in the period 1880–1979 AD. Severe drought, moderate drought, moderate flood, severe flood and normal years account for 15.3%, 25.3%, 11.3%, 6.7%, 41.4% of all years, respectively. Frequency analysis indicates that cooling, warming, drought and flood events show a close relationship to sunspot activity.

Hazard Assessments of Riverbank Flooding and Backward Flows in Dike-Through Drainage Ditches during Moderate Frequent Flooding Events in the Ningxia Reach of the Upper Yellow River (NRYR)

In this study, the riverbank inundation caused by moderate frequent flooding events (with recurrence periods of less than 20 years), along with the increasingly serious hazards of backward flows in dike-through drainage ditches in the Ningxia Reach of the upper Yellow River (NRYR), were investigated. Then, a comprehensive method for hazard assessment of the floodplains and backward flows in the NRYR was proposed, which fully integrated geographical information systems (GISs), remote sensing (RS), and a digital elevation model (DEM), as well as river dynamics theory. This study first established a one-dimensional unsteady hydrodynamic model for the NRYR. The historical flood hydrology observation from 2012, along with the aerial image measurement data of the study area, were used to calibrate and verify the accuracy of the model. The hazards of riverbank inundation and damages to water affected engineering facilities, as well as the backward flows of dike-through drainage ditches caused by the moderate frequent flooding events, were comprehensively analyzed. Also, this study configured the hazard map and proposed revisions to the flood hazard ranking regime definitions, and discussed the impacts and prevention and control measures of moderate frequent flood damages. The proposed method could effectively meet the hazard analysis demands of the moderate frequent flooding events in the NRYR.

Species-specific responses of wood growth to flooding and climate in floodplain forests in Central Germany

Abstract: With ongoing climate change, episodes of severe flooding are predicted to become more frequent despite a general trend towards increasing summer drought. We investigated how wood growth of adult trees of two species characteristic of floodplain forests in Central Germany (Fraxinus excelsior L., Quercus robur L.) and two less-typical species (Acer pseudoplatanus L., Carpinus betulus L.) responded to both maximum stream water level and climate, with a special focus on the effects of the extraordinary flood of the Saale River in June 2013 and the extreme drought in summer 1976. Tree-ring widths were measured on wood cores, and standardized ARSTAN tree-ring chronologies were produced. Using variance partitioning as well as linear mixed-effects models, we compared the effects of monthly values for maximum water level, temperature and precipitation sum on tree-ring width. Further, we calculated resistance, resilience and recovery of the tree species to the extreme events of flooding in 2013 and drought in 1976. Wood growth of all species studied, and particularly of F. excelsior, responded positively to the extraordinary flooding in June 2013. However, in the best models for the characteristic floodplain forest species (F. excelsior and Q. robur), mainly precipitation (F. excelsior) or a combination of precipitation and wood growth of the previous year (Q. robur) acted as drivers of wood growth of the current year. In contrast, growth of the less habitat-specific species (A. pseudoplatanus) mainly showed a significant response to the combination of temperature and wood growth of the previous year. C. betulus was the only species studied that benefited from the extreme drought in 1976. However, two years afterwards, only the wood growth of A. pseudoplatanus was still reduced, while F. excelsior and Q. robur fully recovered. In comparison to other regions in Central Europe, the moderate flood regime of the Saale River seems to have the potential to mitigate effects of summer drought in this region, which is one of the driest in Germany. Thus, increased flooding frequency might, to some degree, reduce drought effects brought about by climate change as well.

Contrasting rainfall-runoff characteristics of floods in desert and Mediterranean basins

Abstract. Catchment-scale hydrological studies on drylands are lacking because of the scarcity of consistent data: observations are often available at the plot scale, but their relevance for the catchment scale remains unclear. A database of 24 years of stream gauge discharge and homogeneous high-resolution radar data over the eastern Mediterranean allows us to describe the properties of floods over catchments spanning from desert to Mediterranean climates, and we note that the data set is mostly of moderate intensity floods. Comparing two climatic regions, desert and Mediterranean, we can better identify specific rainfall-runoff properties. Despite the large differences in rainfall forcing between the two regions, the resulting unit peak discharges and runoff coefficients are comparable. Rain depth and antecedent conditions are the most important properties to shape flood response in Mediterranean areas. In deserts, instead, storm core properties display a strong correlation with unit peak discharge and, to a lesser extent, with runoff coefficient. In this region, an inverse correlation with mean catchment annual precipitation suggests also a strong influence of local surface properties. Preliminary analyses suggest that floods in catchments with wet headwater and dry lower section are more similar to desert catchments, with a strong influence of storm core properties on runoff generation.

Impact of sea-salt on morpho-physiological and biochemical responses in banana (Musa acuminata cv. Berangan).

Banana is often grown in coastal-regions, and while known for itssensitivity towards seawater, little is documented on the effect of sea-salt on the growth, physiology and metal homeostasis. Here we report that banana plantlets exposed to sea-salt at extreme (average seawater concentration; 52.7dSm-1), severe (28.5dSm-1) or moderate (10.2dSm-1) salinity levels had reduced root length (2.0-6.0-fold), plant height (1.2-1.6-fold), leaf number (2.0-2.3-fold) and leaf area (3.3-4.0-fold) compared to control plantlets. Degradation of pigments (total chlorophyll: 1.3-12.3-fold, chlorophyll a: 1.3-9.2-fold; chlorophyll b: 1.3-6.9-fold lower and carotenoids: 1.4-3.7-fold lower) reflected vulnerability of photosystems to salt stress. Relative water content showed a maximum decrease of 1.5-fold in salt stress. MDA analysis showed sea-salt exposure triggers 2.3-3.5-fold higher lipid peroxidation. Metal content analysis showed a 73-fold higher Na value from roots exposed to extreme salinity compared to control plantlets. While phenotype was clearly affected, moderate salinity showed no significant alteration of macro (N, P, K and Ca) and micro (Fe, Mn and Cu) metal content. The antioxidant enzymes: SOD (3.2-fold), CAT (1.7-fold) and GR (6-fold) showed higher activity at moderate salinity level compared to control plantlets but lower activity at severe (SOD: 1.3-fold; CAT: 1.5-fold; GR: 2-fold lower) and extreme seawater salinity (SOD: 1.5; CAT: 1.9; GR: 1.3-fold lower). Mild changes in growth and physiology at sea-salt levels equivalent to moderate seawater flooding, indicate that banana will survive such flooding, while extreme seawater inundation will be lethal. This data provides a reference for future salinity-mediated work in banana.

Short-term effects of moderate and severe floods on infectious diarrheal diseases in Anhui Province, China

BackgroundPrevious studies showed that floods can lead to diarrheal diseases outbreaks; however, the short-term effects of different severity floods on diarrheal diseases are not clear. This study aims to examine 0–14 days lagged effects of moderate and severe floods on diarrhea in Anhui Province, one heavily flood-prone area in China. MethodsDaily diarrheal cases from January 1, 2013 to August 31, 2017 in 16 cities of Anhui were extracted from the National Notifiable Disease Surveillance System. Meteorological data were obtained, and moderate or severe floods were identified according to Comprehensive Study Group of Major Natural Disasters of the State Science and Technology Commission in China. The quasi-Poisson generalized linear models were applied to evaluate effects of floods on daily diarrheal cases in each city with 0–14 days lag, and we divided post-flood periods into week 1 and week 2, further conducted provincial-level meta-analysis. ResultsImmediate effects of floods on diarrheal diseases were observed within 7 days, and at provincial level moderate floods had a RR of 1.05 (95% CI: 1.02–1.09) and severe floods RR = 1.04 (95% CI: 1.01–1.08) controlling for population size, temperature and relative humidity etc., but less effects appeared in the second week. Impacts of flooding on diarrheal diseases varied among cities. Moderate floods in week 1 had a RR of 1.51 (95% CI: 1.29–1.78) in Bozhou, and severe floods had a RR = 1.31 (95% CI: 1.05–1.64) in Chuzhou. The severe floods may have higher RR in week 1 compared with moderate floods in Anqing (1.10 vs 1.06), Chuzhou (1.31 vs 1.07) and Luan (1.18 vs 1.00). ConclusionsBoth moderate and severe floods can significantly increase diarrheal risks in one week with regionally varied effects, and severe floods may lead higher risks. The findings have implications for preparing emergent interventions in hazard periods to reduce health risks of floods.

GIS digital mapping of flood hazard in Jeddah–Makkah region from morphometric analysis

Floods are considered to be one of the natural disasters that seriously affect people’s lives and property every year. Although, delineation and determination of hydrologic basins and their morphometric parameters are difficult morphological tasks, GIS-based approach simplifies the investigation of various morphometric factors and helps to explore the correlation between the drainage morphometry and landform properties. The present study is aimed to investigate the spatial distribution of drainage basins around Jeddah–Makkah region and its surrounding areas (nearly 40,247 km2) using GIS spatial analysis. The morphometric parameters of these drainage basins and their channel systems were estimated and calculated. The computed morphometric parameters are categorized into the following three main groups: linear, aerial, and relief features. The documentation of these parameters was, then, used to evaluate and construct flood hazard map of the region. Flood hazard map assesses five classes with varying degrees (very low, low, moderate, high, and very high) of flood hazard zones. Such hydrological hazard is mostly due to the basin’s area and its highest relief ratio, relative relief, and ruggedness factor. The flood hazard map shows that the city of Jeddah is in a moderate to high flood hazard zone, but most of the areas surrounding it are in moderate flood hazard zone. This indicates that during heavy rainfalls, flash flood could be generated in these areas which can be severely affecting the city. In addition, this study shows a remarkable correlation between theoretical concepts, data sets, and field observations, predominantly highlighting the role of geology and geomorphology in influencing the basin morphometry and identity.