scholarly journals Effect of climate change on long-term river geometric variation in Andong Dam watershed, Korea

2020 ◽  
Author(s):  
Jong Mun Lee ◽  
Jungkyu Ahn ◽  
Young Do Kim ◽  
Boosik Kang
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Environmental Changes ◽  
River Regulation ◽  
Large River ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Output Analysis ◽  
Integrated Method ◽  
Geometric Variation

Abstract Because of multifunctional weirs installed as part of large river regulation works in Korea, water quality problems have arisen from environmental changes in tandem with decreased flow rates. However, there has been limited research into the green algae removal effect, water quality improvement in congested waters, dam and weir operations, and consequential riverbed changes. Studies regarding outflow in a basin, the application and development of sediment load output analysis methods, feasibility of related dam operations, and riverbed patterns have been separately performed. However, basins and rivers should be analyzed by an integrated method instead of an individual one. Therefore, in the present study, the effect of congestion on a river connected to a dam/weir and estuary bank was analyzed based on climate change scenarios HadGEM3-RA RCP 4.5 and 8.5, with the aim of integrating individual studies using watershed and river models. Flow was controlled by dam- and weir-related discharge simulations. Variations in the riverbed caused by the transfer of suspended load in the downstream region were analyzed for both long and short durations. The results of this analysis suggest that given future climate change scenarios, the width of the river and riverbed variations in the riverbed are expected to rise.

Impact of climate change on streamflow and water quality in the upper Dong Nai river basin, Vietnam

2018 ◽  
pp. 70-79 ◽  
Author(s):  
Le Viet Thang ◽  
Dao Nguyen Khoi ◽  
Ho Long Phi
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
River Basin ◽  
Sediment Load ◽  
Swat Model ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Nutrient Load ◽  
Impact Of Climate Change ◽  
The Impact

In this study, we investigated the impact of climate change on streamflow and water quality (TSS, T-N, and T-P loads) in the upper Dong Nai River Basin using the Soil and Water Assessment Tool (SWAT) hydrological model. The calibration and validation results indicated that the SWAT model is a reasonable tool for simulating streamflow and water quality for this basin. Based on the well-calibrated SWAT model, the responses of streamflow, sediment load, and nutrient load to climate change were simulated. Climate change scenarios (RCP 4.5 and RCP 8.5) were developed from five GCM simulations (CanESM2, CNRM-CM5, HadGEM2-AO, IPSL-CM5A-LR, and MPI-ESM-MR) using the delta change method. The results indicated that climate in the study area would become warmer and wetter in the future. Climate change leads to increases in streamflow, sediment load, T-N load, and T-P load. Besides that, the impacts of climate change would exacerbate serious problems related to water shortage in the dry season and soil erosion and degradation in the wet season. In addition, it is indicated that changes in sediment yield and nutrient load due to climate change are larger than the corresponding changes in streamflow.

scholarly journals Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management

2017 ◽  
Author(s):  
Marie Arnoux ◽  
Florent Barbecot ◽  
Elisabeth Gibert-Brunet ◽  
John Gibson ◽  
Aurélie Noret
Keyword(s):  
Water Quality ◽  
Water Balance ◽  
Isotopic Composition ◽  
Sustainable Management ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Rapid Development ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Lake Water Quality

Abstract. Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent change in water use may further exasperate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and for sustainable management of lake water quality into the future. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely Representative Concentration Pathways (RCP) 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (therefore climate conditions), lake catchment size (which impacts the intensity of the flux change), lake volume (which impacts the range of variation), and lake G-index (i.e., the percentage of groundwater that makes up total lake inflows), the latter being the dominant control on water balance conditions, as revealed by the sensitivity of lake isotopic composition. Based on these model simulations, stable isotopes appear to be especially useful for detecting changes in recharge to lakes with a G-index of between 50 % and 80 %, but response is non-linear. Simulated monthly trends reveal that evolution of annual lake isotopic composition can be dampened by opposing monthly recharge fluctuations. It is also shown that changes in water quality in groundwater-connected lakes depend significantly on lake location and on the intensity of recharge change.

scholarly journals Macrofaunal diversity gradients in Antarctic rocky benthic communities: Effects of glaciers and depth

2018 ◽  
Author(s):  
Luis Miguel Pardo ◽  
Ignacio Garrido ◽  
Paulina Bruning ◽  
Charlotte Carrier ◽  
Rossana Reveco ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Diversity ◽  
Salinity Tolerance ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Benthic Communities ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Rocky Subtidal ◽  
Diversity Gradients

Western Antarctic shows one of the fastest responses to climate change on Earth. Glacier meltdown and freshening are perhaps the most conspicuous evidence of anthropogenic impacts, that together with ice scouring can strongly modify benthic communities. The spatial extension of these impacts has been rarely explored in rocky subtidal environments. This study describes changes in benthic communities across glacier and bathymetric gradient in Fildes Bay, Antarctica. Suction samples were taken from four sites at increasing distance from the Collin glacier (0 - 2.5 – 5 - 7 km) and three depths (5 – 10 - 15 m). Macrofaunal diversity increased with depth across all distances from the glacier; these changes were associated with the increase in diversity of amphipods and echinoderms. The lowest and highest species diversity occurred at zero and two km from the glacier, indicating a strong, but localized, glacier effect. Variation in salinity tolerance and the abundance of key habitat forming algae could explain the spatial variation in these communities. This result remarks the importance of facilitation as a structuring force in Antarctic benthic communities. We suggest that the fate of communities in future climate-change scenarios will depend on how habitat-forming species respond to these environmental changes.

scholarly journals Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management

2017 ◽  
Vol 21 (11) ◽  
pp. 5875-5889 ◽  
Author(s):  
Marie Arnoux ◽  
Florent Barbecot ◽  
Elisabeth Gibert-Brunet ◽  
John Gibson ◽  
Aurélie Noret
Keyword(s):  
Water Quality ◽  
Water Balance ◽  
Isotopic Composition ◽  
Sustainable Management ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Rapid Development ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
The Future

Abstract. Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent changes in water use may further exacerbate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and sustainable management of lake water quality into the future. In this context, the aim of the present paper is to determine if the future evolution of the climate, the population, and the recharge could modify the geochemistry of lakes (mainly isotopic signature and quality via phosphorous load) and if the isotopic monitoring of lakes could be an efficient tool to highlight the variability of the water budget and quality. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely representative concentration pathways (RCPs) 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (and therefore climate conditions), lake catchment size (which impacts the intensity of the flux change), lake volume (which impacts the range of variation), and lake G index (i.e., the percentage of groundwater that makes up total lake inflows), the latter being the dominant control on water balance conditions, as revealed by the sensitivity of lake isotopic composition. Based on these model simulations, stable isotopes appear to be especially useful for detecting changes in recharge to lakes with a G index of between 50 and 80 %, but response is non-linear. Simulated monthly trends reveal that evolution of annual lake isotopic composition can be dampened by opposing monthly recharge fluctuations. It is also shown that changes in water quality in groundwater-connected lakes depend significantly on lake location and on the intensity of recharge change.

Irish bathing sites closures and Stormwater Overflows: Precipitation forecasts, extremes analysis, and comparison with climate change projections

2021 ◽  
Author(s):  
Angelos Alamanos ◽  
Alec Rolston ◽  
Suzanne Linnane
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Goodness Of Fit ◽  
Added Value ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Water Utility ◽  
Worst Case ◽  
Daily Precipitation Data ◽  
The Future

<p>During the summer of 2020, five bathing sites in Ireland were closed for the full season because of bad water quality, and 12 more received warnings and closed temporarily. Wastewater and sewage discharges, and Stormwater Overflows (SWOs) were the main causes. Although SWOs are not regarded as a management priority, they contributed to almost every bathing site’s closure, sharpening other existing issues. In this study, the precipitation in Ireland was analysed to inform a national stakeholder forum (An Fóram Uisce/The Water Forum), which provides guidance on water management to the national government, and the national water utility on the rainfall-driven SWOs issues. A correlation analysis of the observations of the closest meteorological stations of each bathing site is presented, showing that there are significant variances across the country, and each area (bathing site) must be examined separately. The Greater Dublin Area (GDA)’s precipitation was then further analysed because eight bathing sites in the GDA are facing SWO problems. Daily, monthly, and annual timeseries (10 years) were studied for peaks, trends, and seasonality. A daily forecast was performed for 1-year, using five techniques, starting from the simplest to the more complex: Seasonal naïve, Seasonal ARIMA, Holt-Winters Seasonal Exponential Smoothing, Non-seasonal ARIMA using seasonality as an exogenous covariate, and Christiano-Fitzgerald filtering. The peculiarities of the observed GDA’s precipitation timeseries are further highlighted through monthly, seasonal, and annual analyses. The trends showed that more extreme events (higher peaks) occurred over the last 30-20 years, thus, a brief extreme analysis was carried out using 120-year daily precipitation data. The Generalised Extreme Value (GEV) distribution was fitted to the historic precipitation using the L-moments method, and was compared to other theoretical distributions, commenting on their goodness of fit. Additionally, by comparing the historic data of temperature and rainfall from all the stations, with the respective reported projections of the future climate change scenarios, all stations we found to have already faced greater ranges than the predicted (e.g. the GDA has already experienced 45% higher temperature than forecast by the worst-case climate change predictions). Overall, the analysis indicates that water quality deterioration from SWOs caused by heavy rainfall events is forecast to become more frequent in the future. Consequently, managing authorities need to pay more attention to SWOs, instead of continuing to consider them as an occasional problem impacting water quality. This is the first study in the country approaching the issue of bathing water quality from the perspective of precipitation analysis. Very few similar rainfall analyses have been carried out in Ireland, thus this work has also a significant added value to the Irish climate literature.</p>

scholarly journals Macrofaunal diversity gradients in Antarctic rocky benthic communities: Effects of glaciers and depth

2018 ◽  
Author(s):  
Luis Miguel Pardo ◽  
Ignacio Garrido ◽  
Paulina Bruning ◽  
Charlotte Carrier ◽  
Rossana Reveco ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Diversity ◽  
Salinity Tolerance ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Benthic Communities ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Rocky Subtidal ◽  
Diversity Gradients

Western Antarctic shows one of the fastest responses to climate change on Earth. Glacier meltdown and freshening are perhaps the most conspicuous evidence of anthropogenic impacts, that together with ice scouring can strongly modify benthic communities. The spatial extension of these impacts has been rarely explored in rocky subtidal environments. This study describes changes in benthic communities across glacier and bathymetric gradient in Fildes Bay, Antarctica. Suction samples were taken from four sites at increasing distance from the Collin glacier (0 - 2.5 – 5 - 7 km) and three depths (5 – 10 - 15 m). Macrofaunal diversity increased with depth across all distances from the glacier; these changes were associated with the increase in diversity of amphipods and echinoderms. The lowest and highest species diversity occurred at zero and two km from the glacier, indicating a strong, but localized, glacier effect. Variation in salinity tolerance and the abundance of key habitat forming algae could explain the spatial variation in these communities. This result remarks the importance of facilitation as a structuring force in Antarctic benthic communities. We suggest that the fate of communities in future climate-change scenarios will depend on how habitat-forming species respond to these environmental changes.

scholarly journals Mapping current and potential future distributions of the oak tree (Quercus aegilops) in the Kurdistan Region, Iraq

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Nabaz R. Khwarahm
Keyword(s):  
Climate Change ◽  
Habitat Suitability ◽  
Environmental Variables ◽  
Climate Changes ◽  
Future Climate ◽  
Annual Precipitation ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Kurdistan Region ◽  
Oak Tree

Abstract Background The oak tree (Quercus aegilops) comprises ~ 70% of the oak forests in the Kurdistan Region of Iraq (KRI). Besides its ecological importance as the residence for various endemic and migratory species, Q. aegilops forest also has socio-economic values—for example, as fodder for livestock, building material, medicine, charcoal, and firewood. In the KRI, Q. aegilops has been degrading due to anthropogenic threats (e.g., shifting cultivation, land use/land cover changes, civil war, and inadequate forest management policy) and these threats could increase as climate changes. In the KRI and Iraq as a whole, information on current and potential future geographical distributions of Q. aegilops is minimal or not existent. The objectives of this study were to (i) predict the current and future habitat suitability distributions of the species in relation to environmental variables and future climate change scenarios (Representative Concentration Pathway (RCP) 2.6 2070 and RCP8.5 2070); and (ii) determine the most important environmental variables controlling the distribution of the species in the KRI. The objectives were achieved by using the MaxEnt (maximum entropy) algorithm, available records of Q. aegilops, and environmental variables. Results The model demonstrated that, under the RCP2.6 2070 and RCP8.5 2070 climate change scenarios, the distribution ranges of Q. aegilops would be reduced by 3.6% (1849.7 km2) and 3.16% (1627.1 km2), respectively. By contrast, the species ranges would expand by 1.5% (777.0 km2) and 1.7% (848.0 km2), respectively. The distribution of the species was mainly controlled by annual precipitation. Under future climate change scenarios, the centroid of the distribution would shift toward higher altitudes. Conclusions The results suggest (i) a significant suitable habitat range of the species will be lost in the KRI due to climate change by 2070 and (ii) the preference of the species for cooler areas (high altitude) with high annual precipitation. Conservation actions should focus on the mountainous areas (e.g., by establishment of national parks and protected areas) of the KRI as climate changes. These findings provide useful benchmarking guidance for the future investigation of the ecology of the oak forest, and the categorical current and potential habitat suitability maps can effectively be used to improve biodiversity conservation plans and management actions in the KRI and Iraq as a whole.

scholarly journals Water Temperature and Hydrological Modelling in the Context of Environmental Flows and Future Climate Change: Case Study of the Wilmot River (Canada)

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2101
Author(s):  
Christian Charron ◽  
André St-Hilaire ◽  
Taha B.M.J. Ouarda ◽  
Michael R. van den Heuvel
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Environmental Flows ◽  
Low Flow ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Water Abstraction ◽  
Surface Water Flow ◽  
Modelling Studies ◽  
Rcp 8.5

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

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