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• A revised temperature model is built to study the thermal stratification. • The reservoir has a reverse thermal stratification and two overturning in a year. • Low water level can weaken the stability and lengthen the spring overturning. • High inflow volume can strength the stability and defer the spring overturning. Thermal structure plays a significant role in the aquatic ecosystem of reservoirs. In this paper, thermal structure of a large reservoir for water supply in northeast China has been studied. Considering the reservoir has a 150 days icebound period and the ice cover can affect the heat transfer process, we built a revised numerical simulation model based on EFDC to study the temporal and spatial variation of thermal stratification. The absolute mean error (AME) and mean absolute relative error (MARE) between modeled and observed water temperature are 0.40 °C and 7.15%, respectively. The results indicate that the validated model can successfully reproduce the temporal and spatial variation of water temperature. The model results indicate that the reservoir has a reverse thermal stratification in icebound season and there are two over-turning events in a year. Six hypothetical scenarios including the extreme change in the air temperature, inflow discharge, and the water level had been built to quantify the influences of changes in climate and hydrology conditions on the thermal structure. This paper provides a simplified method for the simulation of the water temperature in the reservoir with an icebound season, which can provide a reference for other reservoirs. [ABSTRACT FROM AUTHOR]

Climate change is one of the most serious challenges facing mankind in the 21st century. Extreme climatic events are expected to be more frequent and severe leading to various natural disasters. Vietnam, with more than 70% of the population working in agriculture and having a high density of inhabitants on the coastal plains, is one among those countries heavily impacted by climate change. The aim of this paper is to present a methodology to assess the impacts of climate change on a flood prone area of a coastal river basin in the central region of Vietnam. The hydrological simulations are based on a validated deterministic hydrological model MIKE SHE, which integrates geology, soil, topography, river systems and climate variables. The present-day climate, over the period of 1991–2010, was reasonably simulated by the hydrological model. Future climate (2091–2100) information was obtained from a dynamical downscaling of the global climate models, CCSM3.0, MIROC-medres and ECHAM5 under A2 scenario, using the Regional Climate Model: Weather Research and Forecasting Model. The result indicates that with this area, the ensemble future river flow under scenario A2 might increase up to 200% during rainy season and reduce to roughly 7–30% during dry season. The study also analyzed the changes in the flood dynamics of the study region, the hydrological shift and the uncertainties of climate change simulation. This paper showcases an operational approach to integrate the results from the impacts of climate change to flood protection measures that would help in devising resilience strategies. [ABSTRACT FROM AUTHOR]

• The potential changes in future streamflow due to changing climate could be very significant. Therefore, Land development in the area should carefully consider the future climatic variations. • Sustainable water management strategies must be applied in the catchment to overcome the water shortage issues. • The anticipated drier climate could change the flow regimes and harm the biodiversity of the Peel-Harvey Estuary. • Adaptive responses would be necessary to maintain sustainable ecological communities. • The findings are useful to manage the usage of future water resources in the catchment by considering the low flow situation. This paper presents an assessment of the impacts of future climate changes on the hydrological characteristics of Harvey River catchment in Western Australia. A conceptual lumped-parameter rainfall-runoff model (HBV model) is used to simulate the catchment hydrological behaviour. Daily observations of rainfall, temperature and discharge and monthly mean potential evapotranspiration from the hydro-meteorological stations within the catchment were used to calibrate and validate the HBV model. The calibrated model was then forced by the downscaled future rainfall and temperature to simulate the daily discharge at the catchment outlet for the mid (2046–2065) and late (2080–2099) of the 21st century. Future climate signals were extracted from a multi-model ensemble of eight Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under three Representative Concentration Pathways (RCPs) (RCP2.6, RCP4.5 and RCP8.5). A control run, with the baseline climatic period (1971–2010), was used to represent the current climate status. Results show a noticeable reduction in the mean annual streamflow during the mid-century particularly for the RCP4.5 relative to the current streamflow. By the end of the century, all scenarios revealed a relatively high decline in the mean annual streamflow especially the RCP4.5. The decline in future streamflow ranged between 17–27% during the mid-century and 23–52% by the end of the century. [ABSTRACT FROM AUTHOR]

• Climate change, hydrological and hydraulic model are combined to analyze runoffs. • Four Global Climate Model: BCC, BNU, CanESM and CSIRO are used. • The future design runoffs and water levels increase in Qu River. • Disaster management and infrastructure construction should be paid more attention to. The impact of climate change on regional hydrological extreme events has been a research topic that has received much attention in recent years. This paper aims to provide a general overview of changes on future runoffs and water levels in the Qu River Basin, upper reaches of Qiantang River, East China by combining future climate scenarios, hydrological model and 1D hydraulic model. The LARS-WG (Long Ashton Research Station Weather Generator) statistical downscaling method is used to downscale the GCM (Global Climate Model) outputs (including BCC, BNU, CanESM and CSIRO under RCP4.5 and RCP8.5 scenarios) and generate 50 years of synthetic precipitation and maximum and minimum temperatures to drive the GR4J hydrological model and the 1D hydraulic model for the baseline period 1971–2000 and the future period 2021–2050. Finally, the POT (Peaks over Threshold) method is applied to analyze the change of extreme events in the study area. The results show that design runoffs and water levels all indicate an increasing trend in the future period for Changshangang River and Jiangshangang River at most cases, especially for small return periods, and for Qu River the increase becomes larger, which suggests that the risk of flooding will probably become greater and appropriate adaptation measures need to be taken. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides a detailed characterization of the observed daily rainfall series available for the Mekong, Chi, and Mun River Basins in the context of climate change; and describes the linkage between climate simulations given by Global Circulation Models (GCMs) and the local rainfall characteristics using the popular Statistical Downscaling Model (SDSM). Observed daily rainfall records at 11 stations in the study area for the 1961–2007 period were considered. Results of characterizing the available rainfall data for the 1961–1990 and 1991–2007 periods show different trends of rainfall characteristics for different locations in the study area. However, a consistent increase in the annual maximum number of consecutive dry days (CDD) was observed in the Chi catchment area, the eastern part of the Mun watershed, and the western portion of the Mekong River Basin. In addition, decrease in the annual maximum daily rainfall (AMDR) was found in most locations of the study area, except for the central part of the Chi and Mun River Basins. Moreover, it has been shown in this paper that the SDSM could adequately describe the basic statistical and physical characteristics of the observed rainfall processes for the calibration (1961–1975) and validation (1976–1990) periods. This statistical downscaling method was then used to project future rainfall characteristics for the 1961–2099 period using the climate simulations given by the UK HadCM3 (HadCM3) model under A2 and B2 scenarios (HadCM3A2 and HadCM3B2), and by the Canadian GCM3 (CGCM3) model under A2 and A1B scenarios (CGCM3A2 and CGCM3A1B). In general, the projected trends of rainfall characteristics by both HadCM3 and CGCM3 were found to be consistent with the observed historical trends. However, there was a large difference in the projection results given by these two models. This would indicate the presence of high uncertainty in climate simulations provided by different GCMs. In addition, the climate change impacts on the flood and drought problems in the study area were shown using the CDD and AMDR indices of 100-year return period. [Copyright &y& Elsevier]

This paper investigates the effect of gradual and instantaneous sea level rise (SLR) on the seawater intrusion (SWI) process in coastal aquifer systems with different levels of land-surface inundation. A set of hypothetical case studies with different shoreline slopes is used to conduct this numerical experiment. For the purpose of numerical modelling, a future rate of SLR from 2015 to 2100 is considered based on the moderate expectation of the Intergovernmental Panel on Climate Change (IPCC, 2001). The gradual SLR is implemented in two different stages. First, continuous and nonlinear rising of sea level is imposed starting from year 2015 up to the end of the century. After that the final value of sea level is maintained as constant in order to assess the response time spanning to a new steady state condition. The effects of pumping resulting in lowering of groundwater level are also considered together with the dynamic variation of sea level. The results show that the rate and the amount of SWI are considerably greater in aquifers with flat shoreline slopes compared with those with steep slopes. Moreover, a shorter period of time is required to reach a new steady state condition in systems with flatter slopes. The SWI process is followed by a significant depletion in quantity of freshwater resources at the end of the century. The situation is exacerbated with combined action of SLR and over-abstraction. Finally, by considering the effect of inundation of the shoreline due to gradual SLR, the sensitivity of the system to the main aquifer parameters including molecular diffusion of solute, dispersion, hydraulic conductivity and porosity is investigated. [ABSTRACT FROM AUTHOR]

Abstract: The gradual climate change symptoms in many places on Earth have been observed during the last 20 years. There is a significant increase in frequency and extremity of meteorological and hydrological events () that lead to distinct excess or lack of water in landscape. These phenomena affect not only actual quantity of water but also its quality with direct and indirect impacts on aquatic organisms. From the environmental impact point of view, drought events are considered to be more dangerous due to their medium-term to long-term characteristics and large spatial impacts. However, this study presents that the particular flood event had significantly greater impact on water quality than the period of drought even if for only a very short time The paper reviews changes in water quality with all its consequences during selected extreme hydrological situations in the Czech Republic in last 10 years and compares them with the knowledge of impacts of floods and droughts on water quality collected from literature. [Copyright &y& Elsevier]