Alfredo Granados

Quantitative Assessment of Climate Change Vulnerability of Irrigation Demands in Mediterranean Europe

This paper presents an analysis of water resources management under climate change in Southern European River Basin Districts. The analysis is based on the Water Availability and Adaptation Policy Analysis (WAAPA) model, which focuses on the quantitative evaluation of maximum potential water withdrawal for different types of demands. The Water Availability and Adaptation Policy Analysis model performs the simulation of water resources systems at the monthly time scale and allows the estimation of the demand-reliability curve in every subbasin of the river network. Over sixty River Basin Districts of Southern Europe have been analyzed, taking basic information from publicly available databases: basin topology from the Hydro1K database, average runoff from the University of New Hampshire Global Runoff Data Centre (GRDC) composite runoff field, population from the Global Rural–urban Mapping Project (GRUMP) and irrigation area from the Global Map of Irrigated Area dataset. Streamflow monthly time series were obtained from the results of the ENSEMBLES project in four climate scenarios for time horizon 2070–2100. Climate change vulnerability of irrigation demands is estimated from changes in maximum potential water withdrawals for irrigation in current and future scenarios. Maximum potential water withdrawal for irrigation was computed as the largest value of irrigation demand that could be supplied with a given reliability requirement once the existing urban demand is adequately satisfied. The results show significant regional disparities in vulnerability to climate change in the irrigation sector across Europe. The greatest vulnerabilities have been obtained for Southwest Europe (Iberian Peninsula) and some basins in Italy and Greece.

Strategies to reduce water stress in Euro-Mediterranean river basins.

A portfolio of water management strategies now exists to contribute to reach water demand and supply targets. Among them, integrated water resource management has a large potential for reducing water disagreement in water scarcity regions. Many of the strategies are based on well tested choices and technical know-how, with proven benefits for users and environment. This paper considers water management practices that may contribute to reduce disagreement in water scarcity areas, evaluating the management alternatives in the Mediterranean basins of Europe, a region that exemplifies other water scarcity regions in the world. First, we use a model to compute water availability taking into account water management, temporal heterogeneity, spatial heterogeneity and policy options, and then apply this model across 396 river basins. Second, we use a wedge approach to illustrate policy choices for selected river basins: Thrace (Greece), Guadalquivir, Ebro, Tagus and Duero (Spain), Po (Italy) and Rhone (France). At the wide geographical level, the results show the multi-determinant complexities of climate change impacts and adaptation measures and the geographic nature of water resources and vulnerability metrics. At the local level, the results show that optimisation of water management is the dominating strategy for defining adaptation pathways. Results also show great sensitivity to ecological flow provision, suggesting that better attention should be paid to defining methods to estimate minimum ecological flows in water scarcity regions. For all scales, average water resource vulnerability computed by traditional vulnerability indicators may not be the most appropriate measure to inform climate change adaptation policy. This has large implications to applied water resource studies aiming to derive policy choices, and it is especially interesting in basins facing water scarcity. Our research aims to contribute to shape realistic water management options at the regional level and therefore provide information to climate change, agricultural and water policies.

Behavioural barriers in response to climate change in agricultural communities: an example from Kenya

Farmers’ behavioural attitudes towards climate change are complex and poorly understood, making difficult the development of mitigation and adaptation policies that would be accepted and implemented. So far, the scientific literature has not clearly framed behavioural barriers related to the uptake of mitigation and adaptation strategies. Therefore behavioural barriers are frequently not considered in the modelling framework for climate change policy assessments. This paper presents a method that frames farmers’ behavioural barriers and analyses their main determinants in order to incorporate behavioural constraints in the modelling frameworks. Three focus group discussions and a household survey were carried out in order to assess farmers’ behavioural barriers taking into account the perspectives of both farmers and agricultural technical advisors. The analytical framework includes Principal Component Analysis to identify behavioural barriers and a binary Logit model to analyse the marginal effects of their main determinants. Farming experience, educational attainment and receiving climate information seem to be the key factors that determine the probability of displaying or not displaying most behavioural barriers. This work presents a method to model behavioural barriers in the context of the adoption of climate change adaptation and mitigation practices. Since a better understanding of behavioural barriers can help to enhance the support of mitigation and adaptation policies to farmers, this study could provide a valuable contribution to the deliberation of climate change policies in Kenya.

Hydrologic Determinants of Climate Change Impacts on Regulated Water Resources Systems

This paper assesses the effect of climate change on water availability for consumptive use for a river basin taking into account the regulation capacity of its water supply systems and a set of management standards (restrictions, demands, reliability). A specific sensitivity index to climate change defined by the relation between the unitary variation of water availability and the unitary variation of the average annual inflow is studied. The analysis is conducted by constructing climate projections taking into consideration changes only in mean annual streamflow and changes in both the mean and the coefficient of variation of the annual streamflow. The study area includes 567 basins which cover practically the entire territory of continental Spain. The results show a significant sensitivity to changes in the coefficient of variation for regulated systems.

Adapting Water Allocation to Irrigation Demands to Constraints in Water Availability Imposed by Climate Change

Climate change projections predict a rise in temperatures which may result in a reduction in water resource availability. Irrigation is both the most demanding water use and that which is the lowest priority. Consequently, adaptation measures regarding irrigation demands are required in coping with such a resource decrease. As improvement in water efficiency use could not be enough to counteract strong stream flow reductions, management actions regarding demands may be implemented. This paper proposes a methodology for identifying the required reductions and sequence in which water allocation is to be reduced in order to meet satisfactory system behaviour. Such a methodology could help basin managers in decision making in meeting irrigation demands which, accordingly, could offer better performance in terms of both reliability and productivity. The methodology is applied at the Guadalquivir Basin in Spain, under eight hydrological projections which represent future climate change scenarios. The results show that it is possible to reduce future water scarcity problems and, hence, improve system performance. In addition to this, it is found that optimal reduction sequence is not only affected by water productivity, but also by the system topology which influences reliability. In the case study, the most sensitive demands are those located at the river head. As such demands have no alternative sources, they typically offer the lowest degree of reliability.