scholarly journals How will climate change modify river flow regimes in Europe?

2013 ◽  
Vol 17 (1) ◽  
pp. 325-339 ◽  
Author(s):  
C. Schneider ◽  
C. L. R. Laizé ◽  
M. C. Acreman ◽  
M. Flörke
Keyword(s):  
Climate Change ◽  
River Flow ◽  
Anthropogenic Impacts ◽  
Flow Characteristics ◽  
Flow Regimes ◽  
Temperate Climate ◽  
Climate Zone ◽  
Natural Flow ◽  
The Mediterranean ◽  
Boreal Climate

Abstract. Worldwide, flow regimes are being modified by various anthropogenic impacts and climate change induces an additional risk. Rising temperatures, declining snow cover and changing precipitation patterns will interact differently at different locations. Consequently, in distinct climate zones, unequal consequences can be expected in matters of water stress, flood risk, water quality, and food security. In particular, river ecosystems and their vital ecosystem services will be compromised as their species richness and composition have evolved over long time under natural flow conditions. This study aims at evaluating the exclusive impacts of climate change on river flow regimes in Europe. Various flow characteristics are taken into consideration and diverse dynamics are identified for each distinct climate zone in Europe. In order to simulate present-day natural flow regimes and future flow regimes under climate change, the global hydrology model WaterGAP3 is applied. All calculations for current and future conditions (2050s) are carried out on a 5' × 5' European grid. To address uncertainty, bias-corrected climate forcing data of three different global climate models are used to drive WaterGAP3. Finally, the hydrological alterations of different flow characteristics are quantified by the Indicators of Hydrological Alteration approach. Results of our analysis indicate that on the European scale, climate change can be expected to modify flow regimes remarkably. This is especially the case in the Mediterranean (due to drier conditions with reduced precipitation across the year) and in the boreal climate zone (due to reduced snowmelt, increased precipitation, and strong temperature rises). In the temperate climate zone, impacts increase from oceanic to continental. Regarding single flow characteristics, strongest impacts on timing were found for the boreal climate zone. This applies for both high and low flows. Flow magnitudes, in turn, will be predominantly altered in the Mediterranean but also in the Northern climates. At the end of this study, typical future flow regimes under climate change are illustrated for each climate zone.

scholarly journals How will climate change modify river flow regimes in Europe?

2012 ◽  
Vol 9 (8) ◽  
pp. 9193-9238 ◽  
Author(s):  
C. Schneider ◽  
C. L. R. Laizé ◽  
M. C. Acreman ◽  
M. Flörke
Keyword(s):  
Climate Change ◽  
Mediterranean Climate ◽  
River Flow ◽  
Anthropogenic Impacts ◽  
Flow Characteristics ◽  
Flow Regimes ◽  
Global Climate Models ◽  
Low Flow ◽  
Climate Zone ◽  
The Mediterranean

Abstract. Worldwide, flow regimes are being modified by various anthropogenic impacts and climate change induces an additional risk. Rising evapotranspiration rates, declining snow cover and changing precipitation patterns will interact differently at different locations. Consequently, in distinct climate zones, unequal consequences can be expected in matters of water stress, flood risk, water quality, and food security. In particular, river ecosystems and their vital ecosystem services will be compromised as their species richness and composition have evolved over long time under natural flow conditions. This study aims at evaluating the exclusive impacts of climate change on river flow regimes in Europe. Various flow characteristics are taken into consideration and diverse dynamics are identified for each distinct climate zone in Europe. In order to simulate natural and modified flow regimes, the global hydrology model WaterGAP3 is applied. All calculations for current and future conditions (2050s) are carried out on a 5' × 5' European grid. To address uncertainty, climate forcing data of three different global climate models are used to drive WaterGAP3. Finally, the hydrological alterations of different flow characteristics are quantified by the Indicators of Hydrological Alteration approach. Results of our analysis indicate that on European scale, climate change can be expected to modify flow regimes significantly. This is especially the case in the Mediterranean climate zone (due to drier conditions with reduced precipitation across the year) and in the continental climate zone (due to reduced snowmelt and drier summers). Regarding single flow characteristics, strongest impacts on timing were found for the boreal climate zone. This applies for both, high and low flows. While low flow magnitudes are likely to be stronger influenced in the Mediterranean climate, high flow magnitudes will be mainly altered in snow climates with warmer summers. At the end of this study, typical future flow regimes under climate change are illustrated for each climate zone including a validation on robustness.

scholarly journals Sensitivity of Regulated Flow Regimes to Climate Change in the Western United States

2018 ◽  
Vol 19 (3) ◽  
pp. 499-515 ◽  
Author(s):  
Tian Zhou ◽  
Nathalie Voisin ◽  
Guoyong Leng ◽  
Maoyi Huang ◽  
Ian Kraucunas
Keyword(s):  
Climate Change ◽  
Water Management ◽  
United States ◽  
River Flow ◽  
Flow Regimes ◽  
Western United States ◽  
Regulated River ◽  
Flow Conditions ◽  
Natural Conditions ◽  
Natural Flow

Abstract Water management activities modify water fluxes at the land surface and affect water resources in space and time. Conventional understanding on the role of water management suggests that regulated river flow would be less sensitive to future climate conditions than natural flow in terms of the absolute changes in mean monthly flows. In this study the authors evaluate such an assumption by redefining sensitivity as the difference in the emergence of changes in cumulative distribution functions (CDFs) of future regulated and natural flows in response to climate change with respect to their respective historical regulated and natural flow conditions. The emergence of changes (shift in CDFs) in natural and regulated river flow regimes across the western United States from simulations driven by multiple climate models and scenarios were compared. Forty percent of Hydrologic Unit Codes 4 (HUC4s) over the western United States might perceive such a shift in seasonal regulated flow earlier than they would have seen in natural flow conditions, although the absolute change is smaller than that under natural conditions. About 10% of the regulated HUC4s see a delay and are therefore less sensitive to climate change. In the spring (MAM), the overall sensitivity tends to decrease as the level of river regulation increases, as expected. However, in the winter (DJF) and summer (JJA) seasons, the sensitivity tends to increase with increasing levels of regulation, with changes in smaller magnitudes than under natural conditions. The results could inform integrated assessment studies when designing adaptation strategies in the water–energy–food nexus.

scholarly journals Impact of climate change on freshwater ecosystems: a global-scale analysis of ecologically relevant river flow alterations

2010 ◽  
Vol 14 (5) ◽  
pp. 783-799 ◽  
Author(s):  
P. Döll ◽  
J. Zhang
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
River Flow ◽  
Flow Regimes ◽  
Freshwater Ecosystems ◽  
Land Area ◽  
Impact Of Climate Change ◽  
Water Withdrawals ◽  
The Impact

Abstract. River flow regimes, including long-term average flows, seasonality, low flows, high flows and other types of flow variability, play an important role for freshwater ecosystems. Thus, climate change affects freshwater ecosystems not only by increased temperatures but also by altered river flow regimes. However, with one exception, transferable quantitative relations between flow alterations and ecological responses have not yet been derived. While discharge decreases are generally considered to be detrimental for ecosystems, the effect of future discharge increases is unclear. As a first step towards a global-scale analysis of climate change impacts on freshwater ecosystems, we quantified the impact of climate change on five ecologically relevant river flow indicators, using the global water model WaterGAP 2.1g to simulate monthly time series of river discharge with a spatial resolution of 0.5 degrees. Four climate change scenarios based on two global climate models and two greenhouse gas emissions scenarios were evaluated. We compared the impact of climate change by the 2050s to the impact of water withdrawals and dams on natural flow regimes that had occurred by 2002. Climate change was computed to alter seasonal flow regimes significantly (i.e. by more than 10%) on 90% of the global land area (excluding Greenland and Antarctica), as compared to only one quarter of the land area that had suffered from significant seasonal flow regime alterations due to dams and water withdrawals. Due to climate change, the timing of the maximum mean monthly river discharge will be shifted by at least one month on one third on the global land area, more often towards earlier months (mainly due to earlier snowmelt). Dams and withdrawals had caused comparable shifts on less than 5% of the land area only. Long-term average annual river discharge is predicted to significantly increase on one half of the land area, and to significantly decrease on one quarter. Dams and withdrawals had led to significant decreases on one sixth of the land area, and nowhere to increases. Thus, by the 2050s, climate change may have impacted ecologically relevant river flow characteristics more strongly than dams and water withdrawals have up to now. The only exception refers to the decrease of the statistical low flow Q90, with significant decreases both by past water withdrawals and future climate change on one quarter of the land area. However, dam impacts are likely underestimated by our study. Considering long-term average river discharge, only a few regions, including Spain, Italy, Iraq, Southern India, Western China, the Australian Murray Darling Basin and the High Plains Aquifer in the USA, all of them with extensive irrigation, are expected to be less affected by climate change than by past anthropogenic flow alterations. In some of these regions, climate change will exacerbate the discharge reductions, while in others climate change provides opportunities for reducing past reductions. Emissions scenario B2 leads to only slightly reduced alterations of river flow regimes as compared to scenario A2 even though emissions are much smaller. The differences in alterations resulting from the two applied climate models are larger than those resulting from the two emissions scenarios. Based on general knowledge about ecosystem responses to flow alterations and data related to flow alterations by dams and water withdrawals, we expect that the computed climate change induced river flow alterations will impact freshwater ecosystems more strongly than past anthropogenic alterations.

scholarly journals Water and forests in the Mediterranean hot climate zone: a review based on a hydraulic interpretation of tree functioning

2016 ◽  
Vol 25 (2) ◽  
pp. eR02 ◽  
Author(s):  
Teresa Soares David ◽  
Clara Assunção Pinto ◽  
Nadezhda Nadezhdina ◽  
Jorge Soares David
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Water Resources ◽  
Water Availability ◽  
Forest Growth ◽  
Bibliographic Databases ◽  
Climate Zone ◽  
Hot Climate ◽  
Tree Survival ◽  
The Mediterranean

Aim of the study: Water scarcity is the main limitation to forest growth and tree survival in the Mediterranean hot climate zone. This paper reviews literature on the relations between water and forests in the region, and their implications on forest and water resources management. The analysis is based on a hydraulic interpretation of tree functioning.Area of the study: The review covers research carried out in the Mediterranean hot climate zone, put into perspective of wider/global research on the subject. The scales of analysis range from the tree to catchment levels.Material and Methods: For literature review we used Scopus, Web of Science and Google Scholar as bibliographic databases. Data from two Quercus suber sites in Portugal were used for illustrative purposes.Main results: We identify knowledge gaps and discuss options to better adapt forest management to climate change under a tree water use/availability perspective. Forest management is also discussed within the wider context of catchment water balance: water is a constraint for biomass production, but also for other human activities such as urban supply, industry and irrigated agriculture.Research highlights: Given the scarce and variable (in space and in time) water availability in the region, further research is needed on: mapping the spatial heterogeneity of water availability to trees; adjustment of tree density to local conditions; silvicultural practices that do not damage soil properties or roots; irrigation of forest plantations in some specific areas; tree breeding. Also, a closer cooperation between forest and water managers is needed.Keywords: tree hydraulics; tree mortality; climate change; forest management; water resources.

scholarly journals Climate-driven changes in UK river flows

2015 ◽  
Vol 39 (1) ◽  
pp. 29-48 ◽  
Author(s):  
Jamie Hannaford
Keyword(s):  
Climate Change ◽  
River Flow ◽  
Research Effort ◽  
Flow Regimes ◽  
Trend Detection ◽  
Human Disturbances ◽  
Apparent Contradiction ◽  
River Flows ◽  
Climatic Trend ◽  
The Uk

There is a burgeoning international literature on hydro-climatic trend detection, motivated by the need to detect and interpret any emerging changes in river flows associated with anthropogenic climate change. The UK has a particularly strong evidence base in this area thanks to a well-developed monitoring programme and a wealth of studies published over the last 20 years. This paper reviews this research, with a view to assessing the evidence for climate change influences on UK river flow, including floods and droughts. This assessment is of international relevance given the scale of the research effort in the UK, a densely monitored and data-rich environment, but one with significant human disturbances to river flow regimes, as in many parts of the world. The review finds that changes can be detected in river flow regimes, some of which agree with future change projections, while others are in apparent contradiction. Observed changes generally cannot be attributed to climate change, largely due to the fact that river flow records are limited in length and the identification of short-term trends is confounded by natural variability. A UK ‘Benchmark’ network of near-natural catchments is an internationally significant example of an initiative to enable climate variability to be discerned from direct human disturbances (e.g. abstractions, dam construction). Generally, however, the problem of attribution has been tackled rather indirectly in the UK, as elsewhere, and more efforts are required to attribute change in a more rigorous manner.

Stability of River Flow Regimes

1992 ◽  
Vol 23 (3) ◽  
pp. 137-154 ◽  
Author(s):  
I. Krasovskaia ◽  
L. Gottschalk
Keyword(s):  
Climate Change ◽  
Flow Regime ◽  
Climate Models ◽  
River Flow ◽  
Flow Regimes ◽  
Low Flow ◽  
Future Climate Change ◽  
Mean Annual Temperature ◽  
Economic Policies ◽  
Temperature And Precipitation

One of the most important consequences of future climate change may be an alteration of the surface hydrological balance, including changes in flow regimes, i.e. seasonal distribution of flow and especially the time of occurrence of high/low flow, which is of vital importance for environmental and economic policies. Classification of flow regimes still has an important role for the analyses of hydrological response to climate change as well as for validating climate models on present climatic and hydrologic data, however, with some modifications in the methodology. In this paper an approach for flow regime classification is developed in this context. Different ways of flow regime classification are discussed. The stability of flow regimes is studied in relation to changes in mean annual temperature and precipitation. The analyses have shown that even rather small changes in these variables can cause changes in river flow regimes. Different patterns of response have been traced for different regions of the Nordic countries.

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