Flood Volume Research Articles

Flood resilience: Response of an Australian sub‐tropical riparian rainforest to catastrophic flooding

AbstractRiparian taxa are subject to dynamic, intense, flood‐related stressors, and have evolved traits to persist in this environment. Climate change‐induced intensification of flood regimes pose a threat to these ecosystems, and little is understood about their resilience to this intensification. Following two consecutive major floods (the first flood record‐breaking) along the subtropical coast of eastern Australia in March 2022, we used methods based on persistence (resprouting, seedling recruitment), and floristic structure (height, DBH) and assemblage, to assess the resilience of an old growth riparian rainforest to severe flooding in the 12‐month post‐flooding window. Smallerwoody plants (stems <10 m tall, <30 cm DBH) were the most impacted and were significantly impacted by flooding. Native species richness and plant density (plants/m−2) significantly decreased between before and 3 months post‐flooding, after which they continued to significantly increase to surpass pre‐flood values. Overall, ~35% of taxa exhibited resprouting, ~28% of taxa exhibited seedling recruitment, and ~11% exhibited both resprouting and recruitment. An additional ~21% native taxa were introduced to the site via seedling recruitment, along with 65 invasive species. Model‐based multivariate analysis showed flooding significantly altered community floristics (p = 0.026) at 3 months. At 12 months post‐flooding the community was recovering, becoming more floristically similar to its pre‐flood composition. The riparian rainforest exhibited high resilience to intense flooding. Impact, persistence, and resilience varied amongplots, and the community took 12 months to move into recovery. We found that persistence, and floristic structure and composition weighted against impact were effective measures of ecosystem resilience. In the absence of further consecutive events, mature‐phase riparian rainforests are likely to be structurally and floristically resilient to climate change‐induced amplification of flood regimes. Further studies should build on this framework to include invasive weed species impacts, for a more accurate assessment of impacts.

Flood vulnerability of inland bridges with foundation scour

Extreme floods can cause water level to rise above bridge superstructures. Following worldwide statistics on hydraulic bridge failure, it becomes essential to generate a comprehensive knowledge base to predict probable bridge failure scenarios under future floods and to identify appropriate countermeasures for flood risk mitigation. With this objective, the study here develops a numerical framework for systematic evaluation of forces on vulnerable bridge components during floods and to understand the global response of inland river-crossing bridges under flood hazards. Computational fluid dynamics (CFD) simulations are performed to calculate hydrodynamic forces on superstructure of a representative bridge for different inundation levels and flood velocities resulting from varied intensity flood events. Hydrodynamic forces on piers and scour depths around foundations are estimated for flood cases considered here. Knowing the forces and scour depths, finite element bridge models with and without scour are developed and analyzed to apprehend its global response and progressive failure under various combinations of water height and velocity. Further, regression relations are proposed to project component-level responses based on which damage state of the bridge under future intense flood events and fragility characteristics could be predicted. Thus, results enable identifying key factors to reduce flood vulnerability of inland bridges.

Climate change impacts on magnitude and frequency of urban floods under scenario and model uncertainties

Many studies have confirmed that climate change leads to frequent urban flooding, which can lead to significant socioeconomic repercussions. However, most existing studies have not evaluated the impacts of climate change on urban flood from both event-scale and annual-scale dimensions. In addition, there are only few studies that simultaneously consider scenario and model uncertainties of climate change, and combine flood risk assessment and uncertainty analysis results to provide practical suggestions for urban drainage system management. This study uses the statistical downscaling method to calculate the design rainfall under ten rainfall return periods of four climate models and three climate change scenarios in 2040s, 2060s, and 2080s in various prefecture-level cities in China. The four climate models are HadGEM2- ES, MPI-ESM-MR, NorESM1-M and FGOALS-g2 models and the three climate change scenarios are constructed by different representative concentration pathways (RCP), namely RCP2.6, RCP4.5 and RCP8.5. On this basis, relying on the generated drainage systems using geographical information and other data, event-scale and annual-scale precipitation are combined to calculate the change ratio of annual flood volume expectation in prefecture-level cities in each future year compared with the current situation. Furthermore, the study evaluates scenario and model uncertainties of climate change, and then comprehensively integrates the flood risk and its uncertainties to provides suggestions for urban drainage system management.

Identification of Possible Incoming Runoff using Different Combinations of Extreme Rainfall Events in a Semi-arid Context: Banas River, Bisalpur Dam Catchment

ABSTRACT Event-based hydrologic models are very useful to predict peak flow and flood volume, particularly in semi-arid regions. In HEC-HMS software methods selected for loss, transformation, routing and base flow were soil conservation service (SCS) curve number (CN), SCS unit hydrograph (UH), Muskingum and recession, respectively. A total of six extreme events from the year 2011 to 2019 were selected, out of which four were used for calibration, one each for validation and application. The developed model can identify the peak discharge and flood volume satisfactorily at 2-hour intervals. During validation performance statistical viz. percent difference in runoff volume (DV%), percent difference in peak flow (DP%), Nash Sutcliffe Efficiency (NSE), percent bias (%BIAS), coefficient of determination (R2) and ratio of the root mean square error to the standard deviation (RSR) were −3.68, −25.93, 0.52, 3.52, 0.53 and 0.69, respectively. The sensitivity analysis revealed that the CN is the highest sensitive parameter followed by the storage time constant (K), which affects the peak discharge. Whereas, for flood volume, CN is the highest sensitive parameter followed by the recession constant (Rc). The relative sensitivity of CN for peak flow and flood volume were 2.11 and 1.73, respectively. Out of center maximum rainfall (CeMR) and cumulative maximum rainfall (CuMR) distribution, CeMR distribution has given higher peak discharge for all rainfall duration. The rainfall characteristics of the 2016 flood event suggest a hypothetical 9-day rainfall duration can be considered. The 9-day event with CeMR gives 70.64% higher discharge as compared to the observed peak discharge during the 2016 flood.

Flooding Resiliency of Surigao del Sur, Caraga Region, Philippines Residences Through Rainwater Catchment and Storage System

Urbanised areas in Northeastern Mindanao have a problem of addressing flooding occurrences. This study primarily aimed to provide insights into how the rainwater catchment system of uptown communities and their cooperation could increase flood resiliency of downtown communities in the Surigao del Sur, Caraga Region, Philippines. This research employed quantitative analysis of the eleven (11) year (2010-2020) data from the Philippine Atmospheric, Geophysical, and Astronomical Services Administration - Hinatuan, Surigao del Sur station. The recommendable optimum rainwater storage capacities for a given number of household occupants, roof areas at run-off efficiency of 90%, and three (3) day rainfall characteristics at 36.9% averaged probability of exceedance were initially determined. Through scenario analysis, uptown communities emptying their rainwater storages before heavy downpour occurs could provide sufficient flood volume reduction and buffer time for downtown communities to prepare. The output of this research is vital in the environmental planning, management, and policies of cities and regions.

UAV Mapping for Flood Routing in Steep and Densely Vegetated Areas: Insights from the Contok River Basin, Garang Watershed, Indonesia

This research utilizes photogrammetry to assess flood routing dynamics in the Contok river basin, a sub-watershed with a challenging landscape characterized by steep slopes, dense vegetation, and meandering patterns. The objectives are to assess Unmanned Aerial Vehicle (UAV) mapping accuracy, evaluate the river's capacity for design flood volumes, quantify the impact of land cover changes on surface runoff, and provide insights for early warning systems and watershed conservation strategies. The study area, encompassing the Contok River Basin, a sub-watershed of the Garang Watershed, covers 7,413 km² and includes a stream length of 5,274 meters in Semarang City, Central Java, Indonesia. This research employed image processing of aerial photographs and satellite imagery. Aerial photos captured using UAV data were utilized to derive elevation data and cross-sectional profiles of the Contok River, essential for understanding channel morphology and hydraulic characteristics. Concurrently, satellite imagery was used for land cover analysis, identifying vegetation and built-up areas that influence surface runoff dynamics. Hydrological analysis was performed to quantify discharge magnitudes, simulated against river cross-sections to evaluate flood behavior under varying scenarios. Our proposed UAV mapping provides adequate accuracy for small and local areas. Furthermore, it remains reliable for flood routing analysis. We discovered that the capacity of the Contok River channel in the downstream area allows it to convey design flood discharges up to a 50-year return period, contrary to the upstream area, it overflows. Notably, the shift from vegetated to built-up and agricultural areas significantly contributes to the 10.6% increase in surface runoff. This research highlights the role of UAV-based photogrammetry in assessing and mitigating flood hazards amidst evolving land cover patterns. It also enhances the understanding of flood dynamics and thus provides insights that will serve as a reference for flood early warning systems, flood management practices, and watershed conservation.

Effects of small rock check dams on channel bed, vegetation diversity, and soil properties 10 years after a severe wildfire in forest micro‐catchments of central eastern Spain

AbstractOne of the most common post‐fire management techniques is the construction of check dams in catchments. However, little research has explored how small check dams impact on bed profile, vegetation diversity and soil properties several years after their construction in Mediterranean ephemeral channels draining micro‐catchments burned by severe wildfires. To fill this gap, this study has evaluated the effects of rock check dams installed about 10 years ago in small catchments after a wildfire in Castilla La Mancha (Central Eastern Spain). The changes in channel morphology, plant diversity as well as a large dataset of soil properties have been analysed close to the check dams in comparison to burned but non‐regulated channels. Neither the channel slope nor bed sediment size significantly changed downstream and upstream of the structures in comparison to the non‐regulated channels. Thanks to the unexploited retention capacity, the studied control works are still able to store the mobilised sediments on occasion of the most intense floods. Higher species richness in both upstream and downstream sections (+64%) was detected, while the plant evenness was not altered compared to the non‐regulated channels. Regarding the soil properties, increases in organic matter (over 200%), nutrients (+72% for N and +152% for P) and some cations (+29% for Ca and +86% for Mg) were measured. Overall, the presence of the rock check dams in the burned micro‐catchments, although improving many key plant and soil characteristics, did not sharply change the hydrological, geomorphological and ecological conditions compared with those of the non‐regulated catchments.

Assessing Reliability, Resilience and Vulnerability of Water Supply from SuDS

In recent decades, the impacts of urbanization on the hydrological cycle have led to an increase in the frequency and magnitude of urban flooding events, and this is also amplified by the effects of climate change. Sustainable Drainage Systems (SuDS) provide a revolutionary change in this field, improving the sustainability and resilience of cities. This research explores the integration of different SuDS with the aim of significantly reducing both the flow volume and celerity of floods in a residual urban catchment area of the metropolitan city of Querétaro (Mèxico), where extreme rainfall frequently occurs. This catchment is a representative suburb of urban pressure and environmental degradation problems. Currently, managing storm water under climate uncertainty through a multi-disciplinary approach is a major concern in this urban area. A 1D–2D coupling model of shallow water equations, the finite volume method, an unstructured meshing method, and a hybrid parallel computing application defined the optimal configuration of SuDS at catchment scale to reduce the flood vulnerability in Querétaro. Specifically, in this paper, we explore the management issues of the proposed SuDS configuration that acts as a water resource system with multiple purposes. A generic simulation model called MODSIM was applied to simulate the designed urban drainage system under a balanced IPCC future climate scenario in terms of reliability, resilience and vulnerability against water scarcity. The proposed hierarchical Reliability–Resilience–Vulnerability approach appears to be effective in evaluating the system performance, showing that the complete satisfaction of non-essential water uses in Querétaro can be assured at a 65% rate of reliability for a large range of reservoir storage conditions.

Evaluating the comprehensive flood impact assessment on the head reach of the Chiniot dam project

The major sources of surface water available to Pakistan are perennial flows of the River Indus and its tributaries i.e. Jhelum and Chenab Rivers. The creation of a reservoir of 0.9 MAF Capacity will cause the water level to rise and reduction in flow velocity on the Chenab River upstream of Chiniot Bridge. Consequently, it will cause sediment deposition which would further increase the water level due to the raised river bed level by deposited sediments. To study this storage, the reservoir has been modelled in HEC-RAS software to assess pre-dam and post-dam scenarios to simulate different conditions of river flow for water surface profile and sediment delta modelling of the reservoir reach, using historical daily water and sediment flows (1985–2022). The results of flood routing showed that the reservoir has attenuated the peak flood volume with safe releases at downstream side with proper operation of spillway gates. The average sediment inflow in the reservoir is worked out to be 38.4 metric tons. The results of sediment modelling and reservoir flood management indicated that after every 05 years of normal reservoir operation, reservoir flushing is recommended. Without sediment flushing, the river bed would be further raised beyond 189.0 m due to incoming sediment, resulting in further rise of water level up to 192.8 m which is the existing crest level of upstream training works of Talibwala Motorway Bridge.

Hyper-resolution flood hazard mapping at the national scale

Abstract. Flood hazard mapping is currently in a transitional phase involving the use of data and methods that were traditionally in the domain of local studies in a regional or nationwide context. Challenges include the representation of local information such as hydrological particularities and small hydraulic structures, as well as computational and labour costs. This paper proposes a methodology of flood hazard mapping that merges the best of the two worlds (local and regional studies) based on experiences in Austria. The analysis steps include (a) quality control and correction of river network and catchment boundary data; (b) estimation of flood discharge peaks and volumes on the entire river network; (c) creation of a digital elevation model (DEM) that is consistent with all relevant flood information, including riverbed geometry; and (d) simulation of inundation patterns and velocities associated with a consistent flood return period across the entire river network. In each step, automatic methods are combined with manual interventions in order to maximise the efficiency and at the same time ensure estimation accuracy similar to that of local studies. The accuracy of the estimates is evaluated in each step. The study uses flood discharge records from 781 stations to estimate flood hazard patterns of a given return period at a resolution of 2 m over a total stream length of 38 000 km. It is argued that a combined local–regional methodology will advance flood mapping, making it even more useful in nationwide or global contexts.

Performance and uncertainty assessment of green roofs for urban flood reduction in a high-density catchment in Ahmedabad, India

Urban flooding poses a significant challenge to the rapidly growing Indian cities. Low-impact development strategies such as green roofs have shown the potential to reduce urban flooding. However, their performance assessment significantly varies across different studies. Therefore, the study's primary objective is to evaluate green roofs in the Indian context. For this evaluation, the green roofs are assessed based on building-level implementation scenarios for a high-density urban area in India for 25%,50%, and 75% application rates and different rainfall intensities (2,3 and 4-h duration and 2,5,10 and 25-year frequencies). Secondly, to probe the variations in the green roof performance across studies, uncertainty contributions to the runoff reduction from different parameters are quantified. The results show that green roofs can reduce up to 62% of flood volume and 24% of runoff. However, they are reasonably effective only beyond 25% application rates. Further, rainfall intensity contributes the most to the uncertainty of runoff reduction from green roofs. This uncertainty assessment implies that localized evaluation of green roofs depending on local rainfall conditions is required for city-wide policy planning. The study has a significant contribution to building confidence in the ability of green roofs to reduce urban floods in the context of developing countries like India.

Nonstationary multi-site design flood estimation and application to design flood regional composition analysis

Impacts of climate change and human activities may lead to changes in the spatiotemporal composition of the design flood as well as its size. Previous studies mainly focused on changes in design flood size, while there has been relatively little research on changes in its regional composition. In this study, a nonstationary multi-site design flood estimation method is developed, which is useful for the design flood regional composition analysis under nonstationary conditions. Dynamic copula models are first constructed to analyze the change in the joint distribution of the nonstationary multi-site flood variables with the consideration of the nonstationarity of the marginal distribution and copula structure parameters. Then the design flood combinations in multi-site for a specified design standard are calculated by comprehensively applying the equivalent reliability method, the expectation conditional and the most-likely conditional combination strategies, which considers the future precipitation change and design lifespan length impacts on the design flood. Finally, the uncertainty of the multi-site design flood estimation caused by the model parameters uncertainty is evaluated. A case study, based on the annual maximum 7-day (AM7) flood volume in the Yichang (YC) and Cuntan (CT) sites, is conducted to illustrate this method. Results show that flood quantiles in the YC and CT sites exhibit an increasing trend as the precipitation projections will increase in the future, but the flood quantiles in the YC site are less compared to the historical period because of the huge regulation and storage effect of the Three Gorges Reservoir. In addition, the design flood combination in the CT and YC sites are calculated and the CT design floods from the expectation combination strategy are bigger than those provided by the most-likely combination strategy.

A combined qualitative–quantitative method for adaptive configuration of urban flood mitigation measure

Inappropriately selecting flood mitigation measures can lead to ineffective governance and wastage of social resources. To address this issue, this research proposes a framework for adaptive configuration of urban flood mitigation measure. This framework aims to achieve a two-sided matching between the disaster reduction capacity of measures and the specific demands of the construction site. The framework was employed to the urban flood mitigation strategy in Longkungou drainage system, an optimal allocation scheme for addressing urban flood disasters under the design rainfall with 50-year return period was determined. The results revealed that green mitigation measures are primarily concentrated in the drainage system within the upstream catchment. Stormwater pumping stations are mainly situated at the drainage outlets and adjacent river channels in the study area. By reducing the water level in the river channel, these stations effectively prevent and manage flood volume resulting from river overflow. As a result of the flood mitigation strategy, the flood volume in the Longkungou drainage system was reduced by 591,186 m3, representing a peak total flood volume reduction rate of 42.44%. The severity of flood disasters in each sub-catchment has significantly diminished, indicating that the flood mitigation strategy has successfully achieved the desired improvement.

Associated impact mechanism of heavy rain and floods in the middle and lower reaches of the Yangtze river basin based on ocean-atmosphere anomaly patterns

Heavy rainfall and flooding disasters are increasing due to global warming. A clear understanding of the mechanism of heavy rain and floods is the basic premise of disaster risk management. However, most previous studies emphasized more on the single anomalous signal from the average state in the whole season, which may neglect the combined influence of multiple signals in the ocean-atmosphere and differential characteristics of anomalous signals at different periods. Here, our study aimed to reveal the possible influence mechanism of heavy rain and floods in the middle and lower reaches of the Yangtze River Basin (MLRYRB) by systematically analyzing the monthly-scale and daily-scale ocean-atmosphere anomaly patterns in the preceding periods of heavy rainfall and flooding events. The results showed that heavy rainfall and flooding events were highly likely to occur in the region one month after El Niño decayed, with the flooding intensity in June having the negative correlation with the sea ice concentration anomaly in the Arctic with a lag of about 5 months (150 days). Besides, North Atlantic Oscillation, Western Pacific subtropical high, blocking, East Asian subtropical westerly jet, and the water vapor fluxes from the Arabian Sea and western Pacific Ocean could be used as the anomalous signals inducing heavy rain and floods. The daily-scale conceptual model inducing heavy rainfall and flooding events was built based on the patterns of all anomalous signals, which detailed the possible impact mechanism of heavy rain and floods in the region. By making targeted forecasts of anomalous signals and using this information in water resources planning and management based on climate mechanisms, it will have a significant impact on water management in the country.

Quantification of the flood mitigation ecosystem service by coupling hydrological and hydrodynamic models

Flood mitigation service provides crucial information for reducing flood disasters and assessing ecosystem capacities by quantifying how much damage is reduced and how many benefiting areas are protected during flood events. However, there remains a gap in the full-process quantification, which results in less precise simulation outcomes. In this study, we introduce a novel methodology to accurately quantify the flood mitigation service of ecosystems by coupling hydrological and hydrodynamic models. We utilized the Hydrological Simulation Program-Fortran (HSPF) model to simulate peak flow and flood volume and then used these data as inputs for the Environmental Fluid Dynamics Code (EFDC) hydrodynamic model to simulate the spatial extent and depth of flood inundation. The contribution and capacity of the ecosystem are reflected through the reduction in peak flow, flood volume, and inundation areas. We used the Nandu Basin flood event in October 2010 as a case study to illustrate our approach, comparing our assessment results with those simulated by the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and the Height Above Nearest Drainage (HAND) model. The results demonstrate that coupling the HSPF model (R2 = 0.93) with the EFDC model (overlap ratio = 83.71 %) allows for precise quantification of flood mitigation service. The process-based hydrological and hydrodynamic models show a high correlation with the simpler and faster InVEST and HAND model simulations, with the full-process models reducing relative errors by 7.66 % and 5.25 % respectively. This study offers a promising approach for accurately and comprehensively assessing flood mitigation ecosystem service and provides a basis for model selection.

Flood Pulse Effects on the Growth of Pseudoplatystoma fasciatum in the Amazon Basin

Fish growth is a fundamental biological process driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors that underpin individual fitness and population dynamics. Interannual variability in river hydrology regarding the intensity and duration of floods and droughts can induce interannual variations in the biotic and abiotic variables that regulate fish growth. However, the understanding of how interannual variability in river hydrology affects fish growth remains limited for most species and ecosystems. We evaluated how inter-annual hydrological variations within the Amazon River basin influence the growth of the catfish Pseudoplaystoma fasciatum. Our research questions were as follows: Do floods lead to the faster growth of P. fasciatum and droughts lead to the slower growth? And do floods and droughts affect all age classes in the same manner? We sampled 364 specimens of P. fasciatum from five sites in the Amazon basin, estimated their growth rates, and related the growth rates to indices of the intensity of floods and droughts. We fitted linear mixed-effects models to test the relationship between growth increments and hydrological indices (with F and D quantifying the intensities of floods and droughts, respectively), age as fixed effects, and basins and Fish ID as random effects. We found an inverse relationship between the increment width in the fish hard parts and hydrological indices. That is, intense floods and droughts negatively affected the growth rates. We also found that the growth of P. fasciatum was no different in years with intense and mild floods across age classes 1–5, although was different for age class 6. However, the growth of P. fasciatum was faster in years of mild droughts for all age classes. Our results showing that the growth of P. fasciatum was slower in years of intense droughts are supported by those of previous studies in the Amazon basin and elsewhere. However, our results showing for the first time that the growth of P. fasciatum is slower in years of intense flooding is the opposite of patterns found in other studies. These results thus suggest that the growth of P. fasciatum is maximized within an optimum range of hydrological conditions, where neither floods nor droughts are intense.

Assessment of the Impact of Land Use and Land Cover Change on the Surface Runoff of Hadejia River System, Kano, Nigeria

Land use and land cover changes, mostly driven by anthropogenic activities, affect the processes of the water cycle. The impacts of land use (LU) and land cover (LC) changes between 1995 and 2015 on the surface runoff of the Hadejia River System (HRS) were investigated. The LULC changes obtained through re-classifications of selected Landsat satellite images and their effects on runoff peak discharges and volumes were assessed using selected hydrologic models for runoff generation and routing available within the HEC-HMS. Physically-based parameters of the models were estimated from the LULC change maps together with a digital elevation model and soil datasets of the basin. The simulated flows from the 90 sub-catchments were routed to the basin outlet afterwards to obtain the accrued effects in the entire river basin. Model results obtained generally revealed significant and varying increases in the runoff peak discharges and volumes within some sub-basins in the whole catchment, though the change was not significant at the basin outlet. In the sub-catchments within Kano and Jigawa states, increase between 15-20% and 10-15% were observed in the peak discharge respectively. These are the areas with the highest increase in agricultural activities and urbanization within the whole catchment. In the entire basin, however, the flood peak discharges and volumes increased by at least 3.57% and 8.18% respectively. From these results, the study concludes that changes were more pronounced in Kano and Jigawa states due to the increase of urbanization and farming activities in those areas, leading to reduction of infiltration and hence, increase in surface runoff. The study successfully outlined the hydrological consequences of land cover changes, emphasizing the importance of sustainable land use and catchment management strategies. Hence, integration of remote sensing, GIS, and the hydrological model (HEC-HMS) can be used to solve hydrological problems in a river basin.

Extreme weather events and their socioeconomic impacts: A remote sensing-based analysis of flood damages

Global warming is a primary cause of change in global climate patterns. Pakistan ranks among the eight nations that have been impacted by global warming. Pakistan is experiencing significant consequences due to the increasing frequency and intensity of floods. A recent flood in 2022 affected 33 million people and destroyed 2.3 million houses. The study used Sentinel-1 data to extract the precise flood extent and its impacts on infrastructure and cropland in Pakistan's Sindh province. According to the results, the recent flood caused extensive damage to about ∼7340 kilometers, from which ∼1220 kilometers of roads were damaged in the Dadu district. A total of ∼4343 acres of settlement areas was affected along with 0.82 million acres of croplands by flood across different districts of Sindh. Pakistan recently experienced a temperature of 40 °C in many cities during May. It is worth noting that the average temperature in Pakistan has been steadily rising over the past 70 years. In addition, numerous cities experienced unprecedented levels of precipitation within a single month and heavy rainfall within a single day. According to the study, the key factors contributing to this severe flood include heavy monsoon rains, extreme temperatures, rapid glacial melting, and inadequate governance. The study suggested potential solutions to avoid this type of crisis in the future, including the green revolution to avoid extreme temperatures, dam constructions, long-term political stability, raising awareness about climate change, and infrastructure advancement.

Quantifying the Impacts of Land-Cover Change on the Hydrologic Response to Hurricane Ida in the Lower Mississippi River Basin

Abstract The Lower Mississippi River basin (LMRB) has experienced significant changes in land cover and is one of the most vulnerable regions to hurricanes in the United States. Here, we study the impacts of land-cover change on the hydrologic response to Hurricane Ida in LMRB. By using an integrated surface–subsurface hydrologic model, Energy Exascale Earth System Model (E3SM) Land Model coupled with the three-dimensional ParFlow subsurface flow model (ELM-ParFlow), we simulate the effects of land-cover change on the flood volume and peak timing induced by rainfall from Hurricane Ida. The results show that land-cover changes from 1850 to 2015, which resulted in a smoother surface and less vegetation, exacerbated both flood peak time and volume induced by Hurricane Ida. The effects of land-cover changes can be decomposed into two mechanisms: a smoother surface routes more water faster to a watershed outlet and less vegetation allows more water to contribute to surface runoff. By comparing scenarios in which the two mechanisms were isolated, we found that changes in soil moisture due to vegetation cover change have more dominant effects on floods in the southern part and changes in Manning’s coefficient have the largest effect on floods in the northern part of the LMRB. The study provides important insights into the complex relationship between land-use, land-cover, and hydrologic processes in coastal regions.

Modeling flood characteristics in the Krueng Keureuto river basin in North Aceh regency using the Jams/J2000 application

Abstract Significant land use changes in the Krueng Keureuto River basin exacerbate flooding annually. Despite intensive flood studies, there’s no mapped information on past and future flood inundation. Flood discharge parameters rely on empirical formulas, overlooking climate factors and flood event data, crucial in flood analysis due to climate change. To comprehensively understand flood characteristics, this research employs the JAMS/J2000 application on climatological data (2010-2020), land use, soil type, and geological maps. Using HRU-Web, Hydrologic Response Units (HRUs) are derived for J2000 modeling, producing four runoff components: overland flow, interflow, fast groundwater, and slow groundwater. Notably, the highest overland flow, or flood runoff, was 23.21 mm on December 26, 2014, with 40.69 mm/day rainfall. Interflow peaked at 6.72 mm on October 8, 2011, with 18.10 mm/day rainfall. Fast groundwater reached 1.28 mm on November 30, 2019, with 13.18 mm/day rainfall, and slow groundwater peaked at 1.04 mm on November 13, 2020, with 48.87 mm/day rainfall. This study provides comprehensive insights into the complex dynamics of flood characteristics in the Krueng Keureuto River basin.