Water resources management and climate change adaptation in Iberian transboundary basins

19:00 Tuesday 28 May




Rodrigo Proença De Oliveira (Portugal) 1; Joana Simões (Portugal) 2; Melissa Nogueira (Brazil) 1

1 - Instituto Superior Técnico - Universidade de Lisboa; 2 - Bluefocus

Water resources planning under climate change is particularly trying in transboundary basins, a condition that cannot be ignored in Europe where transboundary basins cover more than 80% of the continent’s land surface.

The problems of climate adaptation are amplified in transboundary basins because a plan must be agreed across the border, as well as among policy sectors and government levels. The involvement of a larger number of stakeholders and the absence of a common planning, legislative and regulatory framework makes reaching a consensus more difficult.

Yet, strong cooperation is needed to develop an efficient and effective adaptation strategy in transboundary contexts. The sharing of resources generates a common understanding of the arising vulnerabilities that is key for a coordinated response. A joint analysis of the possible actions enlarges the set of options to address the threats, increases its efficacy and avoids transferring vulnerabilities from on part to the other part of the basin. It also ensures that each adaptation measure is implemented where it has the most impact to the whole basin and the least socio-economic cost.

In Southern Europe, the Mediterranean climate and current climate change projections add to these challenges. Water scarcity and substantial flow regulation by large storage reservoirs lead to very specific problems of water shortages, poor water quality and significant impacts to aquatic ecosystems. A large majority of the reservoirs is used for power production and is increasingly equipped with pump-storage systems to store energy produced from renewable sources. The reservoir operation is often dictated by the electricity price in the market, putting additional pressure into water resources.

Given the current climate projections, some drastic adaptation measures will probably be needed, defying the possibility of a step-by-step approach with flexible measures. The inexistence of common river basin organizations requires that governments must take the responsibility to reach a consensus and must be directly involved in coordinating their adaptation efforts.

The presentation will analyse the large transboundary basins in the Iberian Peninsula and, particularly, the Tagus river basin which includes the metropolitan areas of Madrid and Lisbon, some important agricultural areas and a major water transfer to basins in southern Spain. The basin suffers water shortage and water quality problems which will be further aggravated by climate change. The presentation will discuss how adaptation efforts should be considered within the bi-national agreement for managing shared water resources, as well as in the River Basin Management Plans.