scholarly journals Flash-flooding of Ephemeral Streams in the Context of Climate Change

2020 ◽  
Author(s):  
A.M. Camarasa-Belmonte
Keyword(s):  
Climate Change ◽  
River Water ◽  
Flood Control ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Flash Flood ◽  
Intermittent Flow ◽  
Ephemeral Streams ◽  
Basin Scale ◽  
Flood Generation

Ephemeral streams, which are more extended than expected, entail a significant flood risk. Historically they have been underestimated due to their intermittent flow and the lack of knowledge on their hydro-geomorphology. Currently, European legislation recognizes their associated risk and supports research into them, adapting the scale and methodology to their characteristics. Based on the compilation of various works carried out in four Valencian catchments (Eastern Spain), this paper approaches the key questions of rainfall-runoff conversion and flood generation in ephemeral streams, taking into account their hydro-geomorphological specificity. Moreover, the consequences which derive from current environmental changes are addressed in the wider scale of Júcar River Water Authority.The study is based on 5-minute data, registered by the SAIH-Júcar network (Authomatic Hydrological Information System). The investigation has been conducted in two phases. Firstly, key issues determining flash-flood generation at basin scale have been addressed, based on the study of 138 floods, registered between 1989 and 2018, in four Valencian ephemeral streams (Barranc del Carraixet, Rambla de Poyo, Riu Vernissa and Rambla de Gallinera). Secondly, concerning a broader scale (Júcar River Water Authority), the evolution of 698 rain episodes (1989-2007) has been analysed. Finally, the consequences that environmental changes (climatic, anthropogenic and morphogenetic) might mean for flash-flood generation have been discussed.The results show how environmental changes point towards an increase in risk to the detriment of resource. Rain episodes tend to increase in intensity and decrease accumulated precipitation. As a consequence, hydrological connectivity will become more dependent on rain intensity, thus reducing runoff thresholds and basin response times. Anthropic changes enhance this behaviour, reducing infiltration and increasing surface runoff and erosion, while accelerating the hydrological cycle. An increase in process-form disequilibrium in Mediterranean catchments can be expected due to the increase in morphogenetic phases (because of the intensification of events) and a decrease in the efficiency of low-magnitude recovery episodes.Consequently, the behaviour of ephemeral-streams under current climate change conditions points firstly to an increase in intense flash-flood events, which will be difficult to manage with the current flood control measures, and secondly an increase in the general aridity conditions of catchments.

scholarly journals Alteration of the Ecohydrological Status of the Intermittent Flow Rivers and Ephemeral Streams due to the Climate Change Impact (Case Study: Tsiknias River)

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 43
Author(s):  
Soumaya Nabih ◽  
Ourania Tzoraki ◽  
Prodromos Zanis ◽  
Thanos Tsikerdekis ◽  
Dimitris Akritidis ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Assessment Tool ◽  
Land Use Changes ◽  
Anthropogenic Factors ◽  
Intermittent Flow ◽  
Climate Change Scenarios ◽  
Ephemeral Streams ◽  
Extreme Flood ◽  
The Impact

Climate change projections predict the increase of no-rain periods and storm intensity resulting in high hydrologic alteration of the Mediterranean rivers. Intermittent flow Rivers and Ephemeral Streams (IRES) are particularly vulnerable to spatiotemporal variation of climate variables, land use changes and other anthropogenic factors. In this work, the impact of climate change on the aquatic state of IRES is assessed by the combination of the hydrological model Soil and Water Assessment Tool (SWAT) and the Temporary Rivers Ecological and Hydrological Status (TREHS) tool under two different Representative Concentration Pathways (RCP 4.5 and RCP 8.5) using CORDEX model simulations. A significant decrease of 20–40% of the annual flow of the examined river (Tsiknias River, Greece) is predicted during the next 100 years with an increase in the frequency of extreme flood events as captured with almost all Regional Climate Models (RCMs) simulations. The occurrence patterns of hyporheic and edaphic aquatic states show a temporal extension of these states through the whole year due to the elongation of the dry period. A shift to the Intermittent-Pools regime type shows dominance according to numerous climate change scenarios, harming, as a consequence, both the ecological system and the social-economic one.

Comparison and validation of the Pyrenean hydrological cycle simulated by different modeling approaches using in-situ and remote sensing data.

2021 ◽  
Author(s):  
Pere Quintana-Seguí ◽  
Yvan Caballero ◽  
Roxelane Cakir ◽  
Benoît Dewandel ◽  
Youen Grusson ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Remote Sensing ◽  
Soil Moisture ◽  
Water Resources ◽  
Hydrological Cycle ◽  
Temporal Trends ◽  
Daily Streamflow ◽  
Basin Scale ◽  
The Mediterranean

<p>In the Mediterranean, mountainous areas are an important source of water resources. Not only do mountains generate most of runoff, but they also store water in soils, as groundwater in aquifers and as snowpack which melts in spring where it can be diverted and used for agriculture. However, climate change and local anthropic processes are changing the behaviour of the Mediterranean mountainous basins, which is adding uncertainty to water management in an area where water management is already difficult. This is the case of the Pyrenees range between France, Spain and Andorra.</p><p>Hydrological modelling is a valuable tool in order to quantify the continental water cycle and, hence, the water resources as green and blue water. It helps  understanding the underlying processes, simulating variables that are difficult or impossible to observe (e.g. soil moisture, snowpack, or land evaporation), and performing experiments impossible to conduct in the real-world (e.g.: fix the land use in order to assess the impacts of climate change only). However, all that valuable contributions are subjected to model uncertainty,  an issue that should not be neglected and carefully assessed.</p><p>The PIRAGUA project aims at assessing the water resources of the Pyrenees in the past and in the future. To this aim, different models are being deployed and compared with past dataset in a first step (period September 1979 to August 2014). At the scale of the whole Pyrenees, we use the physical-based and semi-distributed hydrological model SWAT and the fully distributed, physically-based, hydrological chain SASER (based on the SURFEX LSM). Furthermore, potential groundwater recharge is also evaluated using a simple water balance approach (RECHARGE). In some selected river basins, including karst systems, the GIS-BALAN hydrogeological model has also been applied. The agreement and disagreement of the models with the observations (when available), and between them, will allow a the detection and quantification of the main sources of uncertainty.</p><p>In this study, we have first validated the simulated streamflow at a selection of non-influenced gauging stations. Not only have we used the usual scores (i.e. KGE), but we have also validated the model temporal trends, comparing them to the observed ones. This will allow attributing (assess the link with climate change) trend changes in influenced stations, where models simulate the natural flow and observations also include human processes. KGE comparisons shown that the models are able to correctly simulate daily streamflow on most natural sub-basins. Then, the main fluxes (evaporation, drainage and runoff) and stocks (soil moisture and snowpack) of the models have been compared at the sub-basin scale, showing the rate of agreement between them. Finally, some variables have been compared to remote sensing products (evaporation, soil moisture and snow cover), in order to expand the validation to other relevant variables.</p>

Climate change and water resources in the Lower Mekong River Basin: putting adaptation into the context

2010 ◽  
Vol 1 (2) ◽  
pp. 103-117 ◽  
Author(s):  
M. Keskinen ◽  
S. Chinvanno ◽  
M. Kummu ◽  
P. Nuorteva ◽  
A. Snidvongs ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Change Adaptation ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Climate Change Impacts ◽  
Mekong River ◽  
Adaptation To Climate Change ◽  
Mekong River Basin ◽  
Spatial And Temporal Scales

Adaptation to climate change has become one of the focal points of current development discussion. This article summarises the findings from a multidisciplinary research project looking at climate change impacts and adaptation in the Mekong River Basin in Southeast Asia. The research highlights the central role that the hydrological cycle has in mediating climate change impacts on ecosystems and societies. The findings indicate that climate change should not be studied in isolation, as there are several other factors that are affecting the hydrological cycle. In the Mekong, the most important such factor is the on-going hydropower development that is likely to induce changes at least as radical as climate change, but with shorter timescales. The article concludes that climate change adaptation should broaden its view to consider environmental changes likely to occur due to different factors at various spatial and temporal scales. It is also important to recognise that climate change adaptation is a dynamic, development-orientated process that should consider also broader socio-political context. To enable this, we propose that an area-based adaptation approach should be used more actively to complement the dominant sector-based approaches.

scholarly journals Climate change in Brazil: perspective on the biogeochemistry of inland waters

2012 ◽  
Vol 72 (3 suppl) ◽  
pp. 709-722 ◽  
Author(s):  
F Roland ◽  
VLM Huszar ◽  
VF Farjalla ◽  
A Enrich-Prast ◽  
AM Amado ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Landscape Fragmentation ◽  
Water Bodies ◽  
Inland Waters ◽  
Running Waters ◽  
Climate Change Scenarios ◽  
Natural Lakes

Although only a small amount of the Earth's water exists as continental surface water bodies, this compartment plays an important role in the biogeochemical cycles connecting the land to the atmosphere. The territory of Brazil encompasses a dense river net and enormous number of shallow lakes. Human actions have been heavily influenced by the inland waters across the country. Both biodiversity and processes in the water are strongly driven by seasonal fluvial forces and/or precipitation. These macro drivers are sensitive to climate changes. In addition to their crucial importance to humans, inland waters are extremely rich ecosystems, harboring high biodiversity, promoting landscape equilibrium (connecting ecosystems, maintaining animal and plant flows in the landscape, and transferring mass, nutrients and inocula), and controlling regional climates through hydrological-cycle feedback. In this contribution, we describe the aquatic ecological responses to climate change in a conceptual perspective, and we then analyze the possible climate-change scenarios in different regions in Brazil. We also indentify some potential biogeochemical signals in running waters, natural lakes and man-made impoundments. The possible future changes in climate and aquatic ecosystems in Brazil are highly uncertain. Inland waters are pressured by local environmental changes because of land uses, landscape fragmentation, damming and diversion of water bodies, urbanization, wastewater load, and level of pollutants can alter biogeochemical patterns in inland waters over a shorter term than can climate changes. In fact, many intense environmental changes may enhance the effects of changes in climate. Therefore, the maintenance of key elements within the landscape and avoiding extreme perturbation in the systems are urgent to maintain the sustainability of Brazilian inland waters, in order to prevent more catastrophic future events.

Determinants of Perception and Impact of Climate Change Induced Events on Livelihood of People in the Haor Area of Kishoreganj, Bangladesh

2021 ◽  
Vol 7 (4) ◽  
pp. 1-17
Author(s):  
Md. Azizul Baten ◽  
Md. Kabir Hossain
Keyword(s):  
Climate Change ◽  
Crop Production ◽  
Flood Control ◽  
Large Scale ◽  
Flash Flood ◽  
Sampling Technique ◽  
Cluster Sampling ◽  
Impact Of Climate Change ◽  
The People ◽  
The Impact

Bangladesh is prone to the danger of different natural calamities and is going to be most affected due to climate change-induced events in the upcoming decades. This study attempted to assess the farmers’ awareness, perception and the impact of climate change on the livelihood of people living in the Haor area of Kishoregang, Bangladesh. A total of 230 respondents were interviewed in the study area (Khatkhal union) using the cluster sampling technique. Only 52.2% of farmers are found to be aware of climate change, 61.7% unaware and 47.8% did not know the consequences of rapid climate change. Climate change and the unavailability of flood control embankments are considered as the main reasons for flash floods. Due to the devastating flash flood that occurred in early April 2017; most of the farmers lost more than two-thirds of their standing crops. Flash flood has a large scale impact on soil degradation. As a consequence of these effects, crop production was observed to be reduced the following year. People from Khoishore village are affected by riverbank erosion while the people from Dalargaon village and Hasimpur village are severely affected by Riverbed fill up. Above 93%, people of three villages opined that there is a severe climate change impact on pisciculture, biodiversity and cultivable land.

scholarly journals Streamflow and its components in Ebinur basin: decoupling of anthropogenic and climatic elements

2021 ◽  
Author(s):  
bao qingling ◽  
ding jianli ◽  
liu jie ◽  
han lijie ◽  
wang yinghui
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Junggar Basin ◽  
Anthropogenic Factors ◽  
Lake Basin ◽  
Infiltration Capacity ◽  
Area Index ◽  
Impact Phase

Detecting and assessing changes in the hydrological cycle and how it responds to a changing environment is essential for maintaining regional ecological security and restoring damaged ecosystems. The Ebinur Lake basin, an important ecological barrier in the Junggar Basin of Xinjiang, China, has undergone significant changes in recent decades as a result of massive eco-rehabilitation projects and increased anthropogenic factors. Former studies concentrated on the effect of environmental changes on total runoff, while studies on runoff components in arid region were absent. To solve the above defects, we separated the study period into three phases based on the heuristic segmentation algorithm：the reference phase (1964-1985) and two impact phases: I (1986-2000) and II (2001-2017). The Variable Infiltration Capacity (VIC) surface models were used to determine the contribution of both human activities and climate change to streamflow along with its components. Based on the VIC model of streamflow splitting, the results showed that surface runoff, baseflow and snowmelt accounted for 20.97%, 60.37% and 23.42% of the annual runoff volume respectively. The differential evolution Markov chain (DEMC) algorithm improved the Nash-Sutcliffe efficiency by 20% over the traditional SCE-UA algorithm, which exceeded 0.6 and reached reliable level. Increases in cropland and forested land were partially contributed by grassland and heathland throughout the study period, While the leaf area index (LAI) of the season of plant growth showed a trend of 0.002 increase per year. Direct human activity was the main factor in the reduction of runoff in impact phase I and indirect human activity in impact phase II, Whereas, in the total impact phase, climate change was the main driver of runoff increase. Our results provide insight into decision making related to water stress in changing circumstances in arid regions.

scholarly journals Regions of intensification of extreme snowfall under future warming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lennart Quante ◽  
Sven N. Willner ◽  
Robin Middelanis ◽  
Anders Levermann
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Observational Data ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Models ◽  
Average Intensity ◽  
High Latitudes ◽  
Future Warming

AbstractDue to climate change the frequency and character of precipitation are changing as the hydrological cycle intensifies. With regards to snowfall, global warming has two opposing influences; increasing humidity enables intense snowfall, whereas higher temperatures decrease the likelihood of snowfall. Here we show an intensification of extreme snowfall across large areas of the Northern Hemisphere under future warming. This is robust across an ensemble of global climate models when they are bias-corrected with observational data. While mean daily snowfall decreases, both the 99th and the 99.9th percentiles of daily snowfall increase in many regions in the next decades, especially for Northern America and Asia. Additionally, the average intensity of snowfall events exceeding these percentiles as experienced historically increases in many regions. This is likely to pose a challenge to municipalities in mid to high latitudes. Overall, extreme snowfall events are likely to become an increasingly important impact of climate change in the next decades, even if they will become rarer, but not necessarily less intense, in the second half of the century.

scholarly journals The Impact of Climate Change on the Resistance of Rice Near-Isogenic Lines with Resistance Genes Against Brown Planthopper

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yun-Hung Kuang ◽  
Yu-Fu Fang ◽  
Shau-Ching Lin ◽  
Shin-Fu Tsai ◽  
Zhi-Wei Yang ◽  
...  
Keyword(s):  
Climate Change ◽  
Resistance Genes ◽  
Environmental Changes ◽  
Gene Pyramiding ◽  
Brown Planthopper ◽  
Inhibitory Effect ◽  
Near Isogenic Lines ◽  
Impact Of Climate Change ◽  
Isogenic Lines ◽  
The Impact

Abstract Background The impact of climate change on insect resistance genes is elusive. Hence, we investigated the responses of rice near-isogenic lines (NILs) that carry resistance genes against brown planthopper (BPH) under different environmental conditions. Results We tested these NILs under three environmental settings (the atmospheric temperature with corresponding carbon dioxide at the ambient, year 2050 and year 2100) based on the Intergovernmental Panel on Climate Change prediction. Comparing between different environments, two of nine NILs that carried a single BPH-resistant gene maintained their resistance under the environmental changes, whereas two of three NILs showed gene pyramiding with two maintained BPH resistance genes despite the environmental changes. In addition, two NILs (NIL-BPH17 and NIL-BPH20) were examined in their antibiosis and antixenosis effects under these environmental changes. BPH showed different responses to these two NILs, where the inhibitory effect of NIL-BPH17 on the BPH growth and development was unaffected, while NIL-BPH20 may have lost its resistance during the environmental changes. Conclusion Our results indicate that BPH resistance genes could be affected by climate change. NIL-BPH17 has a strong inhibitory effect on BPH feeding on phloem and would be unaffected by environmental changes, while NIL-BPH20 would lose its ability during the environmental changes.

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