Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Italie → Designing efficient reservoir filling strategies using seasonal drought forecasts (Ethiopia)

Politecnico di Milano (2018)

Designing efficient reservoir filling strategies using seasonal drought forecasts (Ethiopia)

CAVIGLIONI, LORENZO

Titre : Designing efficient reservoir filling strategies using seasonal drought forecasts (Ethiopia)

Auteur : CAVIGLIONI, LORENZO

Université de soutenance : Politecnico di Milano

Grade : Laurea Magistrale 2018

Résumé partiel
Climate change and growing population are expected to severely affect freshwater availability by the end of 21th century. Many river basins, especially in developing countries, are likely to become more prone to periods of reduced water supply, risking considerable impacts on society, environment, and economy. The construction of new dams has the potential to bring significant social and economic benefits, but in the past several negative impacts have been associated with dam construction. The existing literature concerning optimal or strategic dam planning mainly focused on sizing and siting of dams and its associated impacts ; these are certainly important, but for many dams the most severe impact are not associated to regime operations, but to the construction and the filling phases. The construction phase often requires the resettlement of local populations and the preparation of the construction site, and the subsequent filling phase can have non-negligible implications downstream the dam. Extreme precaution towards downstream impacts would require transiting very high percentages of inflow resulting in multi-decadic filling time. A more efficient strategy for upstream interests would tend to speed up the impoundment of water to maximize hydropower production, generating minimal or negligible inflows for several years downstream. In this process, the hydroclimatic variability plays a key role : if the filling occurs in an extremely wet period, the downstream impact is very low, instead in a dry period the impacts will be amplified. The state of global teleconnections stongly influences the hydroclimatic variability, thus introducing a long-term source of predictability on hydrological fluctuations that can be exploited to design efficient filling operations. This study investigates different reservoir filling strategies, in particular, assessing the role that medium and long-term forecasts can play to better inform the impounding strategy, eventually modulating it over time to adapt to the hydroclimatic variability. The proposed methodology is demonstrated onto the case study of the Omo-Turkana basin in Ethiopia, where the construction and filling of Gibe III dam raised the strong opposition of the local community and international organizations. The thesis suggests a retrospective analysis of Gibe III filling to evaluate the impacts of alternative filling strategies, and demonstrate how the availability of long-term forecasts could prove extremely useful. Rainfall and temperature data necessary for this thesis were retrieved from satellite data comparing and correcting three precipitation remote sensing datasets (TRMM, CHIRPS and TAMSAT) and two temperature remote sensing datasets (MERRA-2 and ORH).

Mots Clés  : previsioni ; teleconnessioni globali ; strategie di riempimento ; siccità ; indici di siccità ; fiume Omo ; lago Turkana ; dataset satellitari ; correzione di bias ; procedura NIPA ; modello ELM

Présentation

Version intégrale (20,3 Mb)

Page publiée le 10 mai 2020