WATER SCARCITY AND DROUGHT IN SRDO RIVER BASIN

WATER SCARCITY AND DROUGHT IN SÔRDO RIVER BASIN University of Minho School of Engineering Territory, Environment and Construction Centre (C-TAC) Author* Maria Adelaide Machado Supervisors: Naim Haie; Co-Supervisor: Luís Filipe Fernandes * machado. adelaide@gmail. com Introduction Drought is a normal component that occurs in all kinds of climate on the planet. It is the most complex of all natural disasters and affects more people than any other risk. Analyses have shown that drought can lead to losses as large as those caused by floods and hurricanes. Knowledge of drought and the effects it can contributed decisively to advance strategies to combat it. The importance of developing an ongoing drought monitoring program in Portugal, is essential for integrated and structured management of this phenomenon. This study identifies major impacts on the Sordo River Basin, local and national institutional responses and proposes a methodology for drought monitoring based on methodologies developed in different countries. The prediction of drought, like the prediction of other catastrophic events, is beyond the reach of science, however, the way people and government prepare for their occurrence is essential for minimizing and mitigating against adverse consequences. Study Area The Sôrdo River Basin, a sub catchment of the Douro basin, is of the situated in the Vila Real district of northern of Portugal, where it covers the areas of Vila Real and Santa Marta de Penaguião (figure 1). Drought is a normal, recurring feature of climate; it occurs in virtually all climatic regimes. It occurs in both high and low rainfall areas. It is a temporary aberration, in contrast to aridity, which is a permanent feature of the climate and is restricted to low rainfall areas. Drought is the consequence of a natural reduction in the amount of precipitation received over an extended period of time, usually a season or more in length, although other climatic factors are often associated with it in many regions of the world that can significantly aggravate the severity of the event. Drought is also related to the timing and the effectiveness of the rainfall events. Thus, each drought year is unique in its climatic characteristics and impacts. Drought 2005 The 2005 drought was one of the worst, if not the most serious since there data records began (1945). When drought was declared on January 31 st , the classes of severe and extreme drought covered 75% of the national territory; , between 31 st July and 31 st August reached applied to 100% of the territory, and continued to do so until late September. The graph on the left illustrates data on Sôrdo dam storage levels. According to data of “Águas de Trásos-Montes and Alto Douro” maximum storage capacity is given as 522. 5 m, and that the minimum level of exploitation is 504. 0 m. . Preparing for the future Factors that may encourage administrative bodies to develop plans to combat the effects of drought are numerous and change from one country to another. These factors may be (i) external; for example the 1986 call to develop plans to combat drought forwarded by the World Meteorological Organization (WMO), or (ii) internal such as the occurrence of severe drought and economic, social and environment factors which also affect the economy and rates of societal development. The successful development of planning strategies to combat the drought effects requires several requirements such as: political recognition of the importance of implementing such policies, the involvement of different social, economic and scientific participants, available finance for creating dedicated departments and above all social awareness that such approaches can contribute in a decisive way to the development of the country. Conclusions The year 2005 was an atypical year in terms of rainfall, since the dry weather reached “severe” and “extreme” classification levels, covering the entire national territory. This situation exposed weaknesses of Portuguese institutions in dealing with this kind of phenomenon. The total lack of preparation resulted in a very late response to the phenomenon. Like the rest of the country, the study area affected by the 2005 drought, with rainfall levels far below normal, as shown in the graph to the right. The graph shows low levels of rainfall during the 2004/2005 hydrological year with levels well below normal between November and January. This must have had serious implications for replenishing the amount of water available across the region. Knowledge of this phenomenon and the specificities of each region or country, is essential for the development of a methodology for drought prediction and mitigation. Using an approach supported by methods already developed and implemented by other countries will requires a that decision makers update their outlook concerning the management of water scarcity and drought. Current management frameworks are resistant to change which requires substantial financial investment, with only a slow return that is often not readily apparent to the decision maker. This study proposes a change in how institutional frameworks deal with drought, based on (i) technical expertise and (ii) political accountability. Uma Escola a Reinventar o Futuro – Semana da Escola de Engenharia - 24 a 27 de Outubro de 2011