scholarly journals Water allocation under climate change

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Pilar Barría ◽  
Ignacio Barría Sandoval ◽  
Carlos Guzman ◽  
Cristián Chadwick ◽  
Camila Alvarez-Garreton ◽  
...  

Chile is positioned in the 20th rank of water availability per capita. Nonetheless, water security levels vary across the territory. Around 70% of the national population lives in arid and semiarid regions, where a persistent drought has been experienced over the last decade. This has led to water security problems including water shortages. The water allocation and trading system in Chile is based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms, where the volume to be granted as permanent and eventual WURs is calculated from statistical analyses of historical streamflow records if available, or from empirical estimations if they are not. This computation of WURs does not consider the nonstationarity of hydrological processes nor climatic projections. This study presents the first large sample diagnosis of water allocation system in Chile under climate change scenarios. This is based on novel anthropic intervention indices (IAI), which were computed as the ratio between the total granted water volume to the water availability within 87 basins in north-central and southern Chile (30°S–42°S). The IAI were evaluated for the historical period (1979–2019) and under modeled-based climatic projections (2055–2080). According to these IAI levels, to date, there are 20 out of 87 overallocated basins, which under the assumption that no further WURs will be granted in the future, increases up to 25 basins for the 2055–2080 period. The results show that, to date most of north-central Chilean catchments already have a large anthropic intervention degree, and the increases for the future period occurs mostly in the southern region of the country (approximately 38°S), which has been considered as possible source of water for large water transfer projects (i.e., water roads). These indices and diagnosis are proposed as a tool to help policy makers to address water scarcity under climate change.

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1078 ◽  
Author(s):  
Alvaro Sordo-Ward ◽  
Alfredo Granados ◽  
Ana Iglesias ◽  
Luis Garrote ◽  
María Bejarano

We evaluated different management alternatives to enhance potential water availability for agriculture under climate change scenarios. The management goal involved maximizing potential water availability, understood as the maximum volume of water supplied at a certain point of the river network that satisfies a defined demand, and taking into account specified reliability requirements. We focused on potential water availability for agriculture and assumed two types of demands: urban supply and irrigation. If potential water availability was not enough to satisfy all irrigation demands, management measures were applied aiming at achieving a compromise solution between resources and demands. The methodological approach consisted of estimation and comparison of runoff for current and future period under climate change effects, calculation of water availability changes due to changes in runoff, and evaluation of the adaptation choices that can modify the distribution of water availability, under climate change. Adaptation choices include modifying water allocation to agriculture, increasing the reservoir storage capacity, improving the efficiency of urban water use, and modifying water allocation to environmental flows. These management measures were evaluated at the desired points of the river network by applying the Water Availability and Adaptation Policy Analysis (WAAPA) model. We simulated the behavior of a set of reservoirs that supply water for a set of prioritized demands, complying with specified ecological flows and accounting for evaporation losses. We applied the methodology in six representative basins of southern Europe: Duero-Douro, Ebro, Guadalquivir, Po, Maritsa-Evros, and Struma-Strymon. While in some basins, such as the Ebro or Struma-Strymon, measures can significantly increase water availability and compensate for a fraction of water scarcity due to climate change, in other basins, like the Guadalquivir, water availability cannot be enhanced by applying the management measures analyzed, and irrigation water use will have to be reduced.


2013 ◽  
Vol 4 (3) ◽  
pp. 302-316
Author(s):  
Qiuan Zhu ◽  
Hong Jiang ◽  
Changhui Peng ◽  
Jinxun Liu ◽  
Xiuqin Fang ◽  
...  

The spatial and temporal variation and uncertainty of precipitation and runoff in China were compared and evaluated between historical and future periods under different climate change scenarios. The precipitation pattern is derived from observed and future projected precipitation data for historical and future periods, respectively. The runoff is derived from simulation results in historical and future periods using a dynamic global vegetation model (DGVM) forced with historical observed and global climate models (GCMs) future projected climate data, respectively. One GCM (CGCM3.1) under two emission scenarios (SRES A2 and SRES B1) was used for the future period simulations. The results indicated high uncertainties and variations in climate change effects on hydrological processes in China: precipitation and runoff showed a significant increasing trend in the future period but a decreasing trend in the historical period at the national level; the temporal variation and uncertainty of projected precipitation and runoff in the future period were predicted to be higher than those in the historical period; the levels of precipitation and runoff in the future period were higher than those in the historical period. The change in trends of precipitation and runoff are highly affected by different climate change scenarios. GCM structure and emission scenarios should be the major sources of uncertainty.


2019 ◽  
Author(s):  
Gabriela C. Gesualdo ◽  
Paulo Tarso S. Oliveira ◽  
Dulce B. B. Rodrigues ◽  
Hoshin V. Gupta

Abstract. Climate change affects the global water cycle and has the potential to alter water availability for food-energy-water production, and for ecosystems services, on regional and local scales. An understanding these effects is crucial to assessing future water availability, and for the development of sustainable management plans. Here, we investigate the influence of anticipated climate change on water security in the Jaguari Basin, which is the main source of freshwater for 9 million people in the Sao Paulo Metropolitan Region (SPMR). First, we calibrate and evaluate a hydrological model using daily observed data, obtaining satisfactory Coefficient of Determination and Kling-Gupta efficiency values for both periods. To represent possible climate change scenarios up to 2095, we consider two International Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP 4.5 and RCP 8.5) and use an ensemble of future projections generated by 17 General Circulation Models (GCMs). These data were used to drive the hydrological model to generate projected scenarios of streamflow. Then we used indicators of water scarcity and vulnerability to carry out a quantitative analysis of provision probability. Our results indicate that streamflow can be expected to exhibit increased interannual variability, significant increases in flow rate between January and March, and an extension of the dry season (currently June to September) until November. The latter includes more than 35 % reduction in streamflow during September through November (with > 50 % reduction in October). Our findings indicate an increased risk of floods and droughts accompanied by an expansion of the basin critical period, and our analysis of the Water Security Indices identifies October and November as the most vulnerable months. Overall, our analysis exposes the fragility of water security in the Sao Paulo metropolitan region, and provides valuable technical and scientific information that can be used to guide regional plans and strategies to cope with potential future water scarcity.


2006 ◽  
Vol 9 ◽  
pp. 3-13 ◽  
Author(s):  
S. Giertz ◽  
B. Diekkrüger ◽  
A. Jaeger ◽  
M. Schopp

Abstract. This paper presents an interdisciplinary scenario analysis to assess the influence of global and regional change on future water availability and water consumption in the Upper Ouémé catchment in central Benin. For the region three development scenarios were evolved. These scenarios are combined with climate change scenarios based on the IPCC (Intergovernmental Panel on Climate Change). In the modelling approach the quantification of the land use/land cover change is performed by the cellular automata model CLUE-S. The future climate scenarios are computed with the regional climate model REMO driven by the global ECHAM model. Using this data different land use and climate change scenarios can be calculated with the conceptual hydrological model UHP-HRU to assess the effects of global changes on the future water availability in Benin. To analyse the future water availability also the water consumption has to be taken into account. Due to high population growth an increase in water need in the future is expected for the region. To calculate the future household water consumption data from a regional survey and demographic projections are used. Development of the water need for animal husbandry is also considered. The first test run of the modelling approach was performed for the development scenario 'business as usual' combined with the IPCC scenario B2 for the year 2025. This test demonstrates the applicability of the approach for an interdisciplinary scenario analysis. A continuous run from 2000–2025 will be simulated for different scenarios as soon as the input data concerning land use/land cover and climate are available.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1560 ◽  
Author(s):  
Meron Taye ◽  
Ellen Dyer ◽  
Feyera Hirpa ◽  
Katrina Charles

Rapid growth of agriculture, industries and urbanization within the Awash basin, Ethiopia, as well as population growth is placing increasing demands on the basin’s water resources. In a basin known for high climate variability involving droughts and floods, climate change will likely intensify the existing challenges. To quantify the potential impact of climate change on water availability of the Awash basin in different seasons we have used three climate models from Coupled Models Inter-comparison Project phase 5 (CMIP5) and for three future periods (2006–2030, 2031–2055, and 2056–2080). The models were selected based on their performance in capturing historical precipitation characteristics. The baseline period used for comparison is 1981–2005. The future water availability was estimated as the difference between precipitation and potential evapotranspiration projections using the representative concentration pathway (RCP8.5) emission scenarios after the climate change signals from the climate models are transferred to the observed data. The projections for the future three periods show an increase in water deficiency in all seasons and for parts of the basin, due to a projected increase in temperature and decrease in precipitation. This decrease in water availability will increase water stress in the basin, further threatening water security for different sectors, which are currently increasing their investments in the basin such as irrigation. This calls for an enhanced water management strategy that is inclusive of all sectors that considers the equity for different users.


2019 ◽  
Vol 23 (12) ◽  
pp. 4955-4968 ◽  
Author(s):  
Gabriela Chiquito Gesualdo ◽  
Paulo Tarso Oliveira ◽  
Dulce Buchala Bicca Rodrigues ◽  
Hoshin Vijai Gupta

Abstract. Climate change affects the global water cycle and has the potential to alter water availability for food–energy–water production, and for ecosystems services, on regional and local scales. An understanding of these effects is crucial for assessing future water availability, and for the development of sustainable management plans. Here, we investigate the influence of anticipated climate change on water security in the Jaguari Basin, which is the main source of freshwater for 9 million people in the São Paulo metropolitan region (SPMR). First, we calibrate and evaluate a hydrological model using daily observed data, obtaining satisfactory coefficient of determination and Kling–Gupta efficiency values for both periods. To represent possible climate change scenarios up to 2095, we consider two International Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP4.5 and RCP8.5) and use an ensemble of future projections generated by 17 general circulation models (GCMs). These data were used to drive the hydrological model to generate projected scenarios of streamflow. We then used indicators of water scarcity and vulnerability to carry out a quantitative analysis of provision probability. Our results indicate that streamflow can be expected to exhibit increased interannual variability, significant increases in flow rate between January and March, and a 2-month extension of the hydrological dry season (currently June to September) until November. The latter includes a more than a 35 % reduction in streamflow during September through November (with a > 50 % reduction in October). Our findings indicate an increased risk of floods and droughts accompanied by an expansion of the basin critical period, and our analysis of the water security indices identifies October and November as the most vulnerable months. Overall, our analysis exposes the fragility of water security in the São Paulo metropolitan region, and provides valuable technical and scientific information that can be used to guide regional plans and strategies to cope with potential future water scarcity.


2018 ◽  
Vol 22 (1) ◽  
pp. 463-485 ◽  
Author(s):  
Marit Van Tiel ◽  
Adriaan J. Teuling ◽  
Niko Wanders ◽  
Marc J. P. Vis ◽  
Kerstin Stahl ◽  
...  

Abstract. Glaciers are essential hydrological reservoirs, storing and releasing water at various timescales. Short-term variability in glacier melt is one of the causes of streamflow droughts, here defined as deficiencies from the flow regime. Streamflow droughts in glacierised catchments have a wide range of interlinked causing factors related to precipitation and temperature on short and long timescales. Climate change affects glacier storage capacity, with resulting consequences for discharge regimes and streamflow drought. Future projections of streamflow drought in glacierised basins can, however, strongly depend on the modelling strategies and analysis approaches applied. Here, we examine the effect of different approaches, concerning the glacier modelling and the drought threshold, on the characterisation of streamflow droughts in glacierised catchments. Streamflow is simulated with the Hydrologiska Byråns Vattenbalansavdelning (HBV-light) model for two case study catchments, the Nigardsbreen catchment in Norway and the Wolverine catchment in Alaska, and two future climate change scenarios (RCP4.5 and RCP8.5). Two types of glacier modelling are applied, a constant and dynamic glacier area conceptualisation. Streamflow droughts are identified with the variable threshold level method and their characteristics are compared between two periods, a historical (1975–2004) and future (2071–2100) period. Two existing threshold approaches to define future droughts are employed: (1) the threshold from the historical period; (2) a transient threshold approach, whereby the threshold adapts every year in the future to the changing regimes. Results show that drought characteristics differ among the combinations of glacier area modelling and thresholds. The historical threshold combined with a dynamic glacier area projects extreme increases in drought severity in the future, caused by the regime shift due to a reduction in glacier area. The historical threshold combined with a constant glacier area results in a drastic decrease of the number of droughts. The drought characteristics between future and historical periods are more similar when the transient threshold is used, for both glacier area conceptualisations. With the transient threshold, factors causing future droughts can be analysed. This study revealed the different effects of methodological choices on future streamflow drought projections and it highlights how the options can be used to analyse different aspects of future droughts: the transient threshold for analysing future drought processes, the historical threshold to assess changes between periods, the constant glacier area to analyse the effect of short-term climate variability on droughts and the dynamic glacier area to model more realistic future discharges under climate change.


2021 ◽  
Vol 07 (03) ◽  
pp. 2150012
Author(s):  
Sahar Farid Yousef

More than one-quarter of the world’s population lives in water-scarce areas, while most countries share at least one transboundary river. If water scarcity is this prevalent, should we expect riparian countries to fight over the water allocation of shared rivers? To answer this question, I develop a modified one-shot three-stage river-sharing game where countries can resort to force to solve their water allocation problem. Using backward induction, I solve for the probability of the downstream country initiating conflict against the upstream country and the likelihood of the latter responding with force to the former’s hostile actions. I test the model empirically using a set of all upstream–downstream riparian dyads with available data from AQUASTAT and the Correlates of War Project for the years 1960–2010. The main contribution of this paper is that it demonstrates how upstream and downstream riparian countries differ in their decision to use force against the other country when experiencing water scarcity. I find that water scarcity increases the likelihood of the downstream country initiating the conflict, but it has no effect on the upstream country’s likelihood of responding with force. If history is a predictor of the future, then the results imply that as more riparian countries become water-scarce, militarized conflicts between upstream and downstream countries are likely to increase, especially if there is heterogeneity in water availability between the riparian dyad.


2021 ◽  

Abstract This book is a collection of 77 expert opinions arranged in three sections. Section 1 on "Climate" sets the scene, including predictions of future climate change, how climate change affects ecosystems, and how to model projections of the spatial distribution of ticks and tick-borne infections under different climate change scenarios. Section 2 on "Ticks" focuses on ticks (although tick-borne pathogens creep in) and whether or not changes in climate affect the tick biosphere, from physiology to ecology. Section 3 on "Disease" focuses on the tick-host-pathogen biosphere, ranging from the triangle of tick-host-pathogen molecular interactions to disease ecology in various regions and ecosystems of the world. Each of these three sections ends with a synopsis that aims to give a brief overview of all the expert opinions within the section. The book concludes with Section 4 (Final Synopsis and Future Predictions). This synopsis attempts to summarize evidence provided by the experts of tangible impacts of climate change on ticks and tick-borne infections. In constructing their expert opinions, contributors give their views on what the future might hold. The final synopsis provides a snapshot of their expert thoughts on the future.


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