Assessment of the Impacts of Climate Change on Hydrological Characteristics of the Mbarali River Sub Catchment Using High Resolution Climate Simulations from CORDEX Regional Climate Models

This study assesses the impacts of climate change on water resources over Mbarali River sub-catchment using high resolution climate simulations from the Coordinated Regional Climate Downscaling Experiment Regional Climate Models (CORDEX_RCMs). Daily rainfall, minimum and maximum temperatures for historical climate (1971-2000) and for the future climate projection (2011-2100) under two Representative Concentration Pathways RCP 8.5 and RCP 4.5 were used as input into the Soil and Water Assessment Tool (SWAT) hydrological model to simulate stream flows and water balance components for the Mbarali River sub-catchment. The impacts of climate change on hydrological conditions over Mbarali river catchment were assessed by comparing the mean values of stream flows and water balance components during the present (2011-2040), mid (2041-2070) and end (2071-2100) centuries with their respective mean values in the baseline (1971-2000) climate condition. The results of the study indicate that, in the future, under both RCP 4.5 and RCP 8.5 emission scenarios, the four main components that determine change in catchment water balance (rainfall, ground water recharge, evaporation and surface runoff) over Mbarali river catchment are projected to increase. While the stream flows are projected to decline in the future by 13.33% under RCP 4.5 and 13.67% under RCP 8.5 emission scenarios, it is important to note that simulated surface runoff under RCP8.5 emission scenario is higher than that which is obtained under the RCP4.5 emission scenario.

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Assessment of the impacts of climate change on maize production in the Wami Ruvu basin of Tanzania

Journal of Water and Climate Change ◽

10.2166/wcc.2016.055 ◽

2016 ◽

Vol 8 (1) ◽

pp. 142-164 ◽

Cited By ~ 3

Author(s):

Philbert Luhunga ◽

Ladslaus Chang'a ◽

George Djolov

Keyword(s):

Climate Change ◽

Climate Models ◽

Regional Climate ◽

Climate Projections ◽

Intergovernmental Panel ◽

Lower Altitude ◽

Rcp 8.5 ◽

Maize Yields ◽

The Impact ◽

Impacts Of Climate Change

The IPCC (Intergovernmental Panel on Climate Change) assessment reports confirm that climate change will hit developing countries the hardest. Adaption is on the agenda of many countries around the world. However, before devising adaption strategies, it is crucial to assess and understand the impacts of climate change at regional and local scales. In this study, the impact of climate change on rain-fed maize (Zea mays) production in the Wami-Ruvu basin of Tanzania was evaluated using the Decision Support System for Agro-technological Transfer. The model was fed with daily minimum and maximum temperatures, rainfall and solar radiation for current climate conditions (1971–2000) as well as future climate projections (2010–2099) for two Representative Concentration Pathways: RCP 4.5 and RCP 8.5. These data were derived from three high-resolution regional climate models, used in the Coordinated Regional Climate Downscaling Experiment program. Results showed that due to climate change future maize yields over the Wami-Ruvu basin will slightly increase relative to the baseline during the current century under RCP 4.5 and RCP 8.5. However, maize yields will decline in the mid and end centuries. The spatial distribution showed that high decline in maize yields are projected over lower altitude regions due to projected increase in temperatures in those areas.

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Quantification of the Expected Changes in Annual Maximum Daily Precipitation Quantiles under Climate Change in the Iberian Peninsula

Proceedings ◽

10.3390/ecws-3-05819 ◽

2018 ◽

Vol 7 (1) ◽

pp. 23 ◽

Cited By ~ 1

Author(s):

Carlos Garijo ◽

Luis Mediero

Keyword(s):

Climate Change ◽

Iberian Peninsula ◽

Climate Models ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Regional Climate ◽

Control Period ◽

Regional Climate Models ◽

The Future

Climate model projections can be used to assess the expected behaviour of extreme precipitations in the future due to climate change. The European part of the Coordinated Regional Climate Downscalling Experiment (EURO-CORDEX) provides precipitation projections for the future under various representative concentration pathways (RCPs) through regionalised Global Climate Model (GCM) outputs by a set of Regional Climate Models (RCMs). In this work, 12 combinations of GCM and RCM under two scenarios (RCP 4.5 and RCP 8.5) supplied by the EURO-CORDEX are analysed for the Iberian Peninsula. Precipitation quantiles for a set of probabilities of non-exceedance are estimated by using the Generalized Extreme Value (GEV) distribution and L-moments. Precipitation quantiles expected in the future are compared with the precipitation quantiles in the control period for each climate model. An approach based on Monte Carlo simulations is developed in order to assess the uncertainty from the climate model projections. Expected changes in the future are compared with the sampling uncertainty in the control period. Thus, statistically significant changes are identified. The higher the significance threshold, the fewer cells with significant changes are identified. Consequently, a set of maps are obtained in order to assist the decision-making process in subsequent climate change studies.

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Climate change impacts on the water and groundwater resources of the Lake Tana Basin, Ethiopia

Journal of Water and Climate Change ◽

10.2166/wcc.2020.126 ◽

2020 ◽

Author(s):

Tibebe B. Tigabu ◽

Paul D. Wagner ◽

Georg Hörmann ◽

Jens Kiesel ◽

Nicola Fohrer

Keyword(s):

Climate Change ◽

Climate Models ◽

Water Cycle ◽

Groundwater Resources ◽

Regional Climate ◽

Climate Change Impacts ◽

Regional Climate Models ◽

Water Balance Components ◽

Lake Tana ◽

Lake Tana Basin

Abstract Climate change impacts on the water cycle can severely affect regions that rely on groundwater to meet their water demands in the mid- to long-term. In the Lake Tana basin, Ethiopia, discharge regimes are dominated by groundwater. We assess the impacts of climate change on the groundwater contribution to streamflow (GWQ) and other major water balance components in two tributary catchments of Lake Tana. Based on an ensemble of 35 bias-corrected regional climate models and a hydrologic catchment model, likely changes under two representative concentration pathways (RCP4.5 and 8.5) are assessed. No or only slight changes in rainfall depth are expected, but the number of rainy days is expected to decrease. Compared to the baseline average, GWQ is projected to decrease whereas surface runoff is projected to increase. Hence, rainfall trends alone are not revealing future water availability and may even be misleading, if regions rely heavily on groundwater.

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Analysis of EURO-CORDEX sub-daily rainfall simulations and derived event characteristics

10.5194/egusphere-egu21-2119 ◽

2021 ◽

Author(s):

Paola Nanni ◽

David J. Peres ◽

Rosaria E. Musumeci ◽

Antonino Cancelliere

Keyword(s):

Climate Change ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Regional Climate Models ◽

Rainfall Event ◽

Historical Period ◽

High Temporal Resolution ◽

Hydrological Hazards ◽

The Future

<p>Climate change is a phenomenon that is claimed to be responsible for a significant alteration of the precipitation regime in different regions worldwide and for the induced potential changes on related hydrological hazards. In particular, some consensus has raised about the fact that climate changes can induce a shift to shorter but more intense rainfall events, causing an intensification of urban and flash flooding hazards. &#160;Regional climate models (RCMs) are a useful tool for trying to predict the impacts of climate change on hydrological events, although their application may lead to significant differences when different models are adopted. For this reason, it is of key importance to ascertain the quality of regional climate models (RCMs), especially with reference to their ability to reproduce the main climatological regimes with respect to an historical period. To this end, several studies have focused on the analysis of annual or monthly data, while few studies do exist that analyze the sub-daily data that are made available by the regional climate projection initiatives. In this study, with reference to specific locations in eastern Sicily (Italy), we first evaluate historical simulations of precipitation data from selected RCMs belonging to the Euro-CORDEX (Coordinated Regional Climate Downscaling Experiment for the Euro-Mediterranean area) with high temporal resolution (three-hourly), in order to understand how they compare to fine-resolution observations. In particular, we investigate the ability to reproduce rainfall event characteristics, as well as annual maxima precipitation at different durations. With reference to rainfall event characteristics, we specifically focus on duration, intensity, and inter-arrival time between events. Annual maxima are analyzed at sub-daily durations. We then analyze the future simulations according to different Representative concentration scenarios. The proposed analysis highlights the differences between the different RCMs, supporting the selection of the most suitable climate model for assessing the impacts in the considered locations, and to understand what trends for intense precipitation are to be expected in the future.</p>

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Modelling the water balance of Lake Victoria (East Africa) – Part 2: Future projections

Hydrology and Earth System Sciences ◽

10.5194/hess-22-5527-2018 ◽

2018 ◽

Vol 22 (10) ◽

pp. 5527-5549 ◽

Cited By ~ 13

Author(s):

Inne Vanderkelen ◽

Nicole P. M. van Lipzig ◽

Wim Thiery

Keyword(s):

Climate Change ◽

Water Balance ◽

Lake Level ◽

Climate Models ◽

Emission Scenario ◽

Lake Victoria ◽

Regional Climate ◽

Regional Climate Models ◽

Management Scenario ◽

Dam Management

Abstract. Lake Victoria, the second largest freshwater lake in the world, is one of the major sources of the Nile river. The outlet to the Nile is controlled by two hydropower dams of which the allowed discharge is dictated by the Agreed Curve, an equation relating outflow to lake level. Some regional climate models project a decrease in precipitation and an increase in evaporation over Lake Victoria, with potential important implications for its water balance and resulting level. Yet, little is known about the potential consequences of climate change for the water balance of Lake Victoria. In this second part of a two-paper series, we feed a new water balance model for Lake Victoria presented in the first part with climate simulations available through the COordinated Regional Climate Downscaling Experiment (CORDEX) Africa framework. Our results reveal that most regional climate models are not capable of giving a realistic representation of the water balance of Lake Victoria and therefore require bias correction. For two emission scenarios (RCPs 4.5 and 8.5), the decrease in precipitation over the lake and an increase in evaporation are compensated by an increase in basin precipitation leading to more inflow. The future lake level projections show that the dam management scenario and not the emission scenario is the main controlling factor of the future water level evolution. Moreover, inter-model uncertainties are larger than emission scenario uncertainties. The comparison of four idealized future management scenarios pursuing certain policy objectives (electricity generation, navigation reliability and environmental conservation) uncovers that the only sustainable management scenario is mimicking natural lake level fluctuations by regulating outflow according to the Agreed Curve. The associated outflow encompasses, however, ranges from 14 m3 day−1 (−85 %) to 200 m3 day−1 (+100 %) within this ensemble, highlighting that future hydropower generation and downstream water availability may strongly change in the next decades even if dam management adheres to he Agreed Curve. Our results overall underline that managing the dam according to the Agreed Curve is a key prerequisite for sustainable future lake levels, but that under this management scenario, climate change might potentially induce profound changes in lake level and outflow volume.

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Assessing Future Impacts of Climate Change on Water Supply System Performance: Application to the Pozzillo Reservoir in Sicily, Italy

Water ◽

10.3390/w11122531 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2531 ◽

Cited By ~ 2

Author(s):

Peres ◽

Modica ◽

Cancelliere

Keyword(s):

Climate Change ◽

Water Supply ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Supply System ◽

Water Supply System ◽

Reservoir Inflow ◽

Emissions Scenario ◽

Impacts Of Climate Change

Climate change induced by greenhouse gas emissions is expected to alter the natural availability of water, affecting domestic, agricultural and industrial uses. This work aims at assessing the possible future impacts of climate change on precipitation, temperature and runoff, and to simulate the effects on reservoir demand–performance curves. To this aim, a modeling chain is set up, based on the combined use of regional climate models (RCMs) and water supply system simulation models. The methodology is applied to the Pozzillo reservoir, located in Sicily (Italy), which has experienced several droughts in the past. We use an RCM model that, based on a previous study, has proved to be the most reliable in the area, among those of the EURO-CORDEX initiative. RCM precipitation and temperature monthly time series are used to generate future reservoir inflow data, according to two representative concentration pathways, RCP4.5 (intermediate emissions scenario) and RCP8.5 (high emissions scenario) and a two-step bias correction procedure. Simulation of the reservoir indicated that, due to reservoir inflow reduction induced by climate change, performances of the Pozzillo reservoir are predicted to decrease significantly in the future, with impacts of RCP8.5 generally higher than RCP4.5.

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Assessment of climate change impact on hydrology of a transboundary river of Bhutan and India

Journal of Water and Climate Change ◽

10.2166/wcc.2021.338 ◽

2021 ◽

Author(s):

Phub Zam ◽

Sangam Shrestha ◽

Aakanchya Budhathoki

Keyword(s):

Climate Change ◽

Climate Models ◽

Assessment Tool ◽

Regional Climate ◽

Flow Simulation ◽

Water Security ◽

Regional Climate Models ◽

Transboundary River ◽

Rcp 8.5 ◽

The Impact

Abstract Assessing the impacts of climate change on a transboundary river plays an important role in sustaining water security within as well as beyond the national boundaries. At times, the unilateral decision taken by one country can increase the risk of negative effect on the riparian countries and if the impact is felt strongly by the other country, it can lead to international tension between them. This study examines the impact of climate change on hydrology between a shared river which is Wangchu river in Bhutan and Raidak river in India. The river is mainly used to produce hydropower in the two largest hydropower plants on which the majority of Bhutan's economic development depends and is mainly used for agriculture in India. The Soil and Water Assessment Tool (SWAT) was used for future flow simulation. Future climate was projected for near future (NF) from 2025–2050 and far future (FF) from 2074–2099 using an ensemble of three regional climate models (ACCESS, CNRM-CM5 and MPI-ESM-LR) for two RCPs (Representative Concentration Pathways), RCP 4.5 and RCP 8.5 scenario. The ensemble results indicated that, in future, the study area would become warmer with temperature increase of 1.5 °C under RCP 4.5 and 3.6 °C under RCP 8.5. However, as per RCP 4.5 and RCP 8.5, rainfall over the study area is projected to decrease by 1.90% and 1.38% respectively. As a consequence of the projected decrease in rainfall, the flow in river is projected to decrease by 5.77% under RCP 4.5 and 4.73% under RCP 8.5. Overall, the results indicated that the degree of hydrological change is expected to be higher, particularly for low flows in both Wangchu and Raidak River. Since transboundary water is a shared for economic growth, climate change adaptation and opportunities should also be considered by both the nations for better water management.

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Assessing the Hydrological Effect of Climate Change on Water Balance of a River Basin in Northern Greece

International Journal of Agricultural and Environmental Information Systems ◽

10.4018/ijaeis.2018100102 ◽

2018 ◽

Vol 9 (4) ◽

pp. 14-33

Author(s):

Panagiota G. Koukouli ◽

Pantazis E. Georgiou ◽

Dimitrios K. Karpouzos

Keyword(s):

Climate Change ◽

Water Balance ◽

River Basin ◽

Climate Models ◽

Baseline Period ◽

Balance Model ◽

Climate Change Scenarios ◽

Northern Greece ◽

Time Periods ◽

Impacts Of Climate Change

In this work, the impacts of climate change on the water resources of the Olynthios River Basin in Northern Greece, were assessed. For this purpose, the climate change scenarios SRES and RCPs were used (SRES A1B, Α2 and RCP4.5, 8.5) - which were taken from two climate models, CGCM3.1/T63 and CanESM2, respectively - for two time periods (2031-2050 and 2081-2100) and for the baseline period (1981-2000). The downscaling was performed using the weather generator ClimGen. The monthly water balance of the Olynthios River Basin was estimated with the use of a conceptual water balance model. Results showed that the annual runoff of the river basin of Olynthios will decrease in response to climate change under all scenarios for both time periods. The results highlight the necessity for adequate adaptation strategies which could improve agricultural water management and reduce the impacts of climate change on agriculture.

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Downscaling of climate change scenarios for a high resolution, site–specific assessment of drought stress risk for two viticultural regions with heterogeneous landscapes

10.5194/esd-2021-9 ◽

2021 ◽

Author(s):

Marco Hofmann ◽

Claudia Volosciuk ◽

Martin Dubrovský ◽

Douglas Maraun ◽

Hans R. Schultz

Keyword(s):

Climate Change ◽

Drought Stress ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Weather Data ◽

Climate Change Scenarios ◽

Research Knowledge ◽

Wine Production ◽

The Future

Abstract. Extended periods without precipitation observed for example in Central Europe including Germany during the seasons from 2018 to 2020, can lead to water deficit and yield and quality losses for grape and wine production. However, irrigation infrastructure is largely non–existent. Regional climate models project changes of precipitation amounts and patterns, indicating an increase in frequency of occurrence of comparable situations in the future. In order to assess possible impacts of climate change on the water budget of grapevines, a water balance model was developed, which accounts for the large heterogeneity of vineyards with respect to their soil water storage capacity, evapotranspiration as a function of slope and aspect, and viticultural management practices. The model was fed with data from soil maps (soil type and plant available water capacity), a digital elevation model, the European Union (EU) vineyard–register, observed weather data and future weather data provided by regional climate models and a stochastic weather generator. This allowed conducting a risk assessment of the drought stress occurrence for the wine–producing regions Rheingau and Hessische Bergstraße in Germany on the scale of individual vineyard plots. The simulations showed that the risk for drought stress varies substantially between vineyard sites but might increase for steep–slope regions in the future. Possible adaptation measures depend highly on local conditions and to make targeted use of the resource water, an intense interplay of different wine-industry stakeholders, research, knowledge transfer, and local authorities will be required.

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