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UNESCO-IHE Institute for Water Education, Delft (2020)

Hydrological drought propagation and societal feedbacks in the Incomati River basin

Tendo, Mark

Titre : Hydrological drought propagation and societal feedbacks in the Incomati River basin

Auteur : Tendo, Mark

Université de soutenance : UNESCO-IHE Institute for Water Education, Delft

Grade : Master of Science (MS) 2020

Résumé
Human influences have become an important part in the drivers of drought in the Anthropocene. Activities such as land use change, damming of rivers, expansion of irrigated agriculture and the cultivation of high water consuming exotic trees can modify the hydrology of catchments and lead to unintended consequences such as the exacerbation of droughts. The measures that societies implement in response to drought such as the excessive abstraction of groundwater ; increase of the storage capacity of reservoirs and increase in irrigation efficiency have also recently been observed to have feedbacks on the occurrence of drought. Recent observations indicate that in some river basins of the world, have unintentionally intensified droughts. Understanding the feedbacks that exist between society and drought propagation is essential in designing sustainable drought response plans. However, the understanding of how drought propagates from meteorological drought through to hydrological drought is still limited. The human influence on the propagation of hydrological drought still needs to be studied in the majority of river basins. This research aims to widen the scope of understanding by studying the influence of society on the propagation of hydrological drought, with the Incomati River basin in South Africa as a case study. The main approach used is the pairing of catchments that are heavily regulated due to for example dams to relatively natural catchments. In some cases comparison between sites upstream and downstream of a dam has been employed. Drought analysis was mainly based on the variable monthly exceedance thresholds of 70 – 95% for both precipitation and discharge. Drought events identified through these thresholds were compared with droughts identified using the standard indices of SPI and SRI at timescales of 1 month, 3 months, and 6 months. Drought characteristics were determined over the entire analysis period of 1981-2018 for ten selected catchments.

Sujets  : drought management hydrological drought human impact case studies South Africa

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Page publiée le 22 avril 2021