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Establishing hydrological monitoring hubs to support the conceptual assessment and protection of Africa’s natural water towers

IWRA World Water Congress 2025 Marrakech Morocco
Groundwater Challenges and Oppotunities
Author(s): Tibor Stigter, Associate Professor, Michel Frem - PhD Researcher

Authors: Tibor Stigter - Associate Professor, Michel Frem, PhD Researcher
IHE Delft Institute for Water Education

Co-authors: Gretchen Gettel, Graham Jewitt, Benson Lombo, Tilahun Azagegn, Binyam Hailu, Petri Pellikka
3 December 2025

Oral: PDF

Abstract

Tropical Mountains – Natural Water Towers

EU project ESSA: IHE Delft responsible for hydrological study of two natural water towers: tropical mountain systems providing freshwater for household use and food production.


▪ Evidence from recharge, discharge and hydrochemistry observations shows that geological faults play an important role in highland – lowland water transmissions.

▪ The main river of Taita Hills changes its behavior along its course, also due to offtake for consumption, becoming "older" and with a stronger lowland signature.

▪ Land use change, in particular increasing cropland area and plantation forest, has decreased the water retention potential of the catchment.

▪ Increased water use is an additional major driver of reduced flow in the dry season, where demand exceeds available flow in dry years.

▪ Strategies for adaptation, including control of water use, reduction of runoff and increase of recharge, will be further evaluated with the model.