scholarly journals Future Flood Risk Assessment under the Effects of Land Use and Climate Change in the Tiaoxi Basin

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6079
Author(s):  
Leilei Li ◽  
Jintao Yang ◽  
Jin Wu
Keyword(s):  
Land Use ◽  
Flood Risk ◽  
Climate Models ◽  
Swat Model ◽  
Climate Projections ◽  
Cultivated Land ◽  
Climate Trend ◽  
The Neural Network ◽  
The Future ◽  
Effects Of Land Use

Global warming and land-use change affects runoff in the regional basin. Affected by different factors, such as abundant rainfall and increased impervious surface, the Taihu basin becomes more vulnerable to floods. As a result, a future flood risk analysis is of great significance. This paper simulated the land-use expansion and analyzed the surface change from 2020 to 2050 using the neural network Cellular Automata Markov (CA-Markov) model. Moreover, the NASA Earth Exchange Global Daily Downscaled Climate Projections (NEX-GDDP) dataset was corrected for deviation and used to analyze the climate trend. Second, the verified SWAT model was applied to simulate future runoff and to analyze the future flood risk. The results show that (1) land use is dominated by cultivated land and forests. In the future, the area of cultivated land will decrease and construction land will expand to 1.5 times its present size. (2) The average annual precipitation and temperature will increase by 1.2% and 1.5 degrees from 2020 to 2050, respectively. During the verified period, the NSE and r-square values of the SWAT model are greater than 0.7. (3) Compared with the historical extreme runoff, the extreme runoff in the return period will increase 10%~25% under the eight climate models in 2050. In general, the flood risk will increase further under the climate scenarios.

Hydrological response of LULC and climate change in Mediterranean basin: application to the  Siliana catchment in Tunisia

2021 ◽  
Author(s):  
Imen EL Ghoul ◽  
Haykel Sellami ◽  
Kaoutar Mounir ◽  
Slaheddine Khlifi ◽  
Marnik Vanclooster
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Swat Model ◽  
Regional Climate ◽  
Climate Projections ◽  
Slight Reduction ◽  
Climate Change Scenarios ◽  
Future Scenarios ◽  
Climate Change Uncertainty ◽  
The Future

<p>Land use/ Land cover (LULC) and climate change are two main factors affecting watershed hydrology. In this study, combined effects of changes in climate and LULC on hydrological processes are investigated by comparing baseline period (2000-2013) to future conditions (2030-2070) using the Soil and Water Assessment Tool (SWAT) hydrological model in the Siliana catchment in Tunisia.</p><p>The LULC future scenarios are modelled using the Cellular Automata (CA)-Markov chain while climate change scenarios were derived from the regional climate models (RCMs) in the coordinated regional climate downscaling experiment (CORDEX-Europe). The (CDF) matching approach with observed precipitation and temperature records is used for bias correction. Subsequently, bias corrected climate projections and LULC future scenarios are fed in the SWAT model to assess changes in catchment hydrology based on a set of hydrological indicators (e.g. monthly discharge and total water availability). Prediction uncertainty related to changes in LULC, climate conditions and SWAT model parameter are also assessed.</p><p>A significant decrease in pasture and an increase in irrigated lands will likely shape the future LULC in comparison to the baseline conditions. However, these changes will be combined by a warmer and drier climate and hydrological conditions in the future in the Siliana catchment. By considering only changes in LULC in the reference period, there was a slight reduction in the surface runoff and total available water in the catchment. </p><p><strong>KEYWORDS:</strong> hydrologic response; land use change; climate change; uncertainty; Mediterranean catchment; SWAT model; CA-Markov</p>

Future projections of river floods hazard over the multiple CORDEX-CORE domains

2020 ◽  
Author(s):  
Francesca Raffaele ◽  
Fabio Di Sante ◽  
Keyword(s):  
East Asia ◽  
Flood Risk ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Global Climate Models ◽  
Climate Projections ◽  
Weather Extremes ◽  
Extreme Precipitation Events ◽  
The Future

<p>One of the most largely recognized effect of the Global Warming is the change of weather extremes. The increase of extreme precipitation events is directly linked to a greater availability of precipitable water induced by a warmer atmosphere.The flood projected signals are heterogeneous and influenced by different phenomena. As an example, the rise in temperature could increase the risk of floods over the regions sensible to extreme precipitations and at the same time could reduce the risk of floods over the regions sensible to the melted snow accumulated during the cold season. In this work the CORDEX-CORE simulations completed using two different Regional Climate Models (RegCM and REMO) are used to estimate the future changes on flood risk for eight CORDEX domains (North-America, Central-America, South-America, Europe, Africa, West-Asia, East-Asia, South-East-Asia and Australasia). A river-routing model is applied to simulate the river discharge of a high resolution grid (0.06 degree) for three different driving Global Climate Models, two different scenarios (rcp2.6 and rcp8.5) and for each of the domains. The simulated discharges are hence used to fit a generalized extreme value (GEV) distribution to estimate the change on flood risk related to the future climate projections.</p>

scholarly journals Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part II: Climate Change Impact Assessment)

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1548
Author(s):  
Suresh Marahatta ◽  
Deepak Aryal ◽  
Laxmi Prasad Devkota ◽  
Utsav Bhattarai ◽  
Dibesh Shrestha
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Models ◽  
Assessment Tool ◽  
Swat Model ◽  
Global Climate Models ◽  
Climate Data ◽  
The Future ◽  
The Impact ◽  
Mountainous River

This study aims at analysing the impact of climate change (CC) on the river hydrology of a complex mountainous river basin—the Budhigandaki River Basin (BRB)—using the Soil and Water Assessment Tool (SWAT) hydrological model that was calibrated and validated in Part I of this research. A relatively new approach of selecting global climate models (GCMs) for each of the two selected RCPs, 4.5 (stabilization scenario) and 8.5 (high emission scenario), representing four extreme cases (warm-wet, cold-wet, warm-dry, and cold-dry conditions), was applied. Future climate data was bias corrected using a quantile mapping method. The bias-corrected GCM data were forced into the SWAT model one at a time to simulate the future flows of BRB for three 30-year time windows: Immediate Future (2021–2050), Mid Future (2046–2075), and Far Future (2070–2099). The projected flows were compared with the corresponding monthly, seasonal, annual, and fractional differences of extreme flows of the simulated baseline period (1983–2012). The results showed that future long-term average annual flows are expected to increase in all climatic conditions for both RCPs compared to the baseline. The range of predicted changes in future monthly, seasonal, and annual flows shows high uncertainty. The comparative frequency analysis of the annual one-day-maximum and -minimum flows shows increased high flows and decreased low flows in the future. These results imply the necessity for design modifications in hydraulic structures as well as the preference of storage over run-of-river water resources development projects in the study basin from the perspective of climate resilience.

scholarly journals Effects of Land Use, Soil Depth and Topography on Soil Physicochemical Properties along the Toposequence at the Wadla Delanta Massif, Northcentral Highlands of Ethiopia

2016 ◽  
Vol 5 (2) ◽  
pp. 57 ◽  
Author(s):  
Nahusenay Abate ◽  
Kibebew Kibret
Keyword(s):  
Land Use ◽  
Physicochemical Properties ◽  
Soil Depth ◽  
Bottom Layer ◽  
Exchange Capacity ◽  
Available Phosphorus ◽  
Soil Physicochemical Properties ◽  
Cultivated Land ◽  
Topographic Positions ◽  
Effects Of Land Use

The study was conducted to investigate the effects of land use, depth and topography on soil physicochemical properties at the Wadla Delanta Massif, northcentral Ethiopia. Four land uses (natural forest, shrub, grazing and cultivated land), three soil depths (0-20, 20-40, 40-60 cm) and three topographic positions (upper, middle and lower) in three replications were considered for this study. A total of 108 composite samples were collected for laboratory analysis. The results show that particle size distribution was affected by the main effects of land use and soil depth; bulk and particle densities, total porosity, organic matter and total nitrogen contents, C:N ratio and available phosphorus were significantly affected by the interaction of land use by soil depth only, whereas, soil pH, electrical conductivity, exchangeable bases, cation exchange capacity, percent base saturation and extractable micronutrients were affected by the interaction effects of the three factors. Highest clay and bulk density were recorded at the bottom layer of the cultivated land soils, while the utmost porosity, organic matter and nitrogen contents, and available phosphorus were recorded at the surface layers of the natural forest land soils. Highest pH was at the bottom layer of the cultivated land at the three topographic positions. Highest exchangeable bases and cation exchange capacity were observed in the bottom layers of soils under the four land use types at the lower topographic position, whilst extractable micronutrients were recorded at the surface layers of the forest land soils at the upper topographic position. In general, most of the measured soil properties were measured better in forest than in other land use soils and the lower topographic positions than the upper and middle ones. Interaction of land use with topography showed negative effects especially on cultivated and grazing land soils in all topographic positions. Therefore, integrated soil fertility management and soil conservation measures are required in all topographic positions to maintain soil physicochemical properties.

scholarly journals Effects of Land Use Types on Selected Soil Properties in Central Highlands of Ethiopia

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Daniel Jaleta Negasa
Keyword(s):  
Land Use ◽  
Soil Properties ◽  
Lower Layer ◽  
Cultivated Land ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Land Use Types ◽  
Sodium Percentage ◽  
Central Highlands ◽  
Effects Of Land Use

Rapid land use changes have been observed in recent years in central Ethiopia. The shift from natural ecosystem to artificial ecosystem is the main direction of change. Therefore, this study was initiated to assess the effects of land use types on selected soil properties in Meja watershed, central highlands of Ethiopia. The randomized complete block design, including three adjacent land use types as treatments with three replications and two soil depths (0–15 and 15–30 cm), was applied in this study. There were significant differences in some soil properties among the three land use types. Lower soil pH and electric conductivity were observed in cultivated land soils than Eucalyptus woodlots soils. This has indicated the worsening soil conditions due to the shift from Eucalyptus woodlots to cultivated land. Less decomposition rate of the Eucalyptus leaves and debris collection for fuel could result in lowest soil organic carbon at the upper layer of Eucalyptus woodlot soils. However, the highest soil organic carbon at the lower layer was observed in Eucalyptus woodlot soils. The presence of highest soil potassium, cation exchange capacity, and exchangeable potassium in cultivated land soil was related to application of artificial fertilizers. Grassland soils have highest exchangeable sodium at the lower layer while highest soil carbon and sum cations at the upper layer, which can be related to the grass root biomass return and less surface runoff on grassland. There was the highest exchangeable sodium percentage on Eucalyptus woodlot soils at the upper layer; it can be due to the less surface nutrient movement and growth characteristics of the tree. The soils in cultivated land was shifted to more acidic and less electric conductivity.This shift can lead to soil quality deterioration that affects the productivity of the soils in the future.Nutrient leaching, application of artificial fertilizer, soil erosion, and continuous farming have affected the soil properties in cultivated land. The presence of highest exchangeable sodium percentage and lowest sum of cations at the upper layer of soil in Eucalyptus woodlot should be noted for management and decision makers. The previous negative speculations on Eucalyptus woodlots which can be related with the soil texture, soil moisture, bulk density, total nitrogen, exchangeable magnesium, calcium, and available sulfur should be avoided because there were no significant differences observed among the three land use types in the study area. The study recommends further studies on the effects of Eucalyptus on soil properties by comparing among different ages and species of Eucalyptus. Finally, planting of Eucalyptus on central highlands of Ethiopia should be supported by land use management decision.

scholarly journals Selection of Bias Correction Methods to Assess the Impact of Climate Change on Flood Frequency Curves

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2266 ◽  
Author(s):  
Enrique Soriano ◽  
Luis Mediero ◽  
Carlos Garijo
Keyword(s):  
Climate Change ◽  
Bias Correction ◽  
Climate Models ◽  
Climate Model ◽  
Control Period ◽  
Flood Frequency ◽  
Climate Projections ◽  
The Future ◽  
Flood Quantiles ◽  
The Impact

Climate projections provided by EURO-CORDEX predict changes in annual maximum series of daily rainfall in the future in some areas of Spain because of climate change. Precipitation and temperature projections supplied by climate models do not usually fit exactly the statistical properties of the observed time series in the control period. Bias correction methods are used to reduce such errors. This paper seeks to find the most adequate bias correction techniques for temperature and precipitation projections that minimizes the errors between observations and climate model simulations in the control period. Errors in flood quantiles are considered to identify the best bias correction techniques, as flood quantiles are used for hydraulic infrastructure design and safety assessment. In addition, this study aims to understand how the expected changes in precipitation extremes and temperature will affect the catchment response in flood events in the future. Hydrological modelling is required to characterize rainfall-runoff processes adequately in a changing climate, in order to estimate flood changes expected in the future. Four catchments located in the central-western part of Spain have been selected as case studies. The HBV hydrological model has been calibrated in the four catchments by using the observed precipitation, temperature and streamflow data available on a daily scale. Rainfall has been identified as the most significant input to the model, in terms of its influence on flood response. The quantile mapping polynomial correction has been found to be the best bias correction method for precipitation. A general reduction in flood quantiles is expected in the future, smoothing the increases identified in precipitation quantiles by the reduction of soil moisture content in catchments, due to the expected increase in temperature and decrease in mean annual precipitations.

scholarly journals Dynamic Land Use Change Prediction and Analysis of Its Impacts on Streamflow for Dabus Watershed, Upper Blue Nile Basin

2021 ◽  
Author(s):  
Neseredin Bashawal Mangel ◽  
Fitsum Berhe
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Swat Model ◽  
Model Performance ◽  
Test Analysis ◽  
Blue Nile Basin ◽  
The Future ◽  
Kappa Value ◽  
Change Prediction ◽  
Basin System

Based on the recorded watershed characteristics, the future conditions on the basin system can be predicted using a different method. In this study, dynamic land-use change and its impacts on the streamflow for the Dabus watershed were predicted using ANN-CA based method. The model performance for accurate prediction of the future land-use change on the Dabus River watershed has been checked by validation of the simulated value with the actual value, hence the overall kappa value (k) = 0.83 for the simulated 2016-LULC validated with actual 2016-LULC. Then, 2026-LULC was predicted based on the 2004 and 2009-LULC. The streamflow for the case of 2004 and 2009-LULC has been simulated using the SWAT model. The value of NSE = 0.87 and 0.90 was attained during validation of simulated streamflow for 2004 and 2009-LULC data cases, respectively. The agreement of simulated value of streamflow with the observed data is indicated as R2 = 0.91 and 0.96 for 2004-LULC and 2009-LULC. The effects of the dynamic land-use change on streamflow for the predicted land use(2026-LULC) catchment were evaluated by T-test analysis. Hence, T-stat =0.04 and -0.002 in the case of simulated streamflow used 2004-LULC and 2009-LULC, respectively compared with simulated value using 2026-LULC.

scholarly journals Drought assessment and trends analysis from 20th century to 21st century over China

2015 ◽  
Vol 371 ◽  
pp. 89-94 ◽  
Author(s):  
X. L. Yang ◽  
L. L. Ren ◽  
R. Tong ◽  
Y. Liu ◽  
X. R. Cheng ◽  
...  
Keyword(s):  
20Th Century ◽  
21St Century ◽  
Climate Models ◽  
Local Economic Development ◽  
Standardized Precipitation Index ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Future Period ◽  
Drought Assessment ◽  
The Future

Abstract. Droughts are becoming the most expensive natural disasters in China and have exerted serious impacts on local economic development and ecological environment. The fifth phase of the Coupled Model Intercomparison Project (CMIP5) provides a unique opportunity to assess scientific understanding of climate variability and change over a range of historical and future period. In this study, fine-resolution multimodel climate projections over China are developed based on 7 CMIP5 climate models under RCP8.5 emissions scenarios by means of Bilinear Interpolation and Bias Correction. The results of downscaled CMIP5 models are evaluated over China by comparing the model outputs with the England Reanalysis CRU3.1 from 1951 to 2000. Accordingly, the results from the output of downscaled models are used to calculate the Standardized Precipitation Index (SPI). Time series of SPI has been used to identify drought from 20th century to 21st century over China. The results show that, most areas of China are projected to become wetter as a consequence of increasing precipitation under RCP8.5 scenarios. Detailed examination shows that the SPI show a slightly increasing trend in the future period for the most parts of China, but drought in Southwest region of China will become the norm in the future RCP8.5 scenarios.

scholarly journals Spatio-temporal trends of hydrological components: the case of the Tafna basin (northwestern Algeria)

2021 ◽  
Author(s):  
Amina Mami ◽  
Djilali Yebdri ◽  
Sabine Sauvage ◽  
Mélanie Raimonet ◽  
José Miguel
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Assessment Tool ◽  
Global Climate ◽  
Swat Model ◽  
Regional Climate ◽  
Temporal Trends ◽  
Regional Climate Models ◽  
Global Climate Models ◽  
The Future

Abstract Climate change is expected to increase in the future in the Mediterranean region, including Algeria. The Tafna basin, vulnerable to drought, is one of the most important catchments ensuring water self-sufficiency in northwestern Algeria. The objective of this study is to estimate the evolution of hydrological components of the Tafna basin, throughout 2020–2099, comparing to the period 1981–2000. The SWAT model (Soil and Water Assessment Tool), calibrated and validated on the Tafna basin with good Nash at the outlet 0.82, is applied to analyze the spatial and temporal evolution of hydrological components, over the basin throughout 2020–2099. The application is produced using a precipitation and temperature minimum/maximum of an ensemble of climate model outputs obtained from a combination of eight global climate models and two regional climate models of Coordinated Regional Climate Downscaling Experiment project. The results of this study show that the decrease of precipitation in January, on average −25%, ranged between −5% and −44% in the future. This diminution affects all of the water components and fluxes of a watershed, namely, in descending order of impact: the river discharge causing a decrease −36%, the soil water available −31%, the evapotranspiration −30%, and the lateral flow −29%.

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