Editors: | F. Kongoli, Z. Wang, T. Okura, E. Souza, A. C. Silva |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 256 pages |
ISBN: | 978-1-987820-94-2 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Knowledge of key hydrological processes and the scale at which they are dominant is still a gap in understanding how mountain catchments function [1]. This is crucial for the sustainable management of water resources as mountain areas are regarded as water towers where the bulk of fresh water is generated [2]. The general effects of land cover types on hydrological processes are known, but estimation of the specific effects in a given catchment is still problematic [3]. This study is examining how herbaceous wetlands dominated by palmiet plants (Prionium serratum) and stands of invasive woody plants (Acacia mearnsii) affect flow paths as well as surface and ground water levels in valley bottoms within a catchment context. An assessment of the appropriate level of complexity required for the prediction of vegetation impacts on hydrological processes is also undertaken.
The Kromme and Baviaanskloof River catchments in the Eastern Cape Province of South Africa were used as case study sites because of their unique nature (narrow valleys with relatively flat valley bottoms) and regional importance for water supply. Through physical characterization, the nature of the groundwater-surface water interactions is being determined and how the valley bottoms are linked to their adjacent steep hillslopes. Data being collected include rainfall, groundwater levels, soil moisture and stream flow. Two models (MIKE SHE and FLEXI Topo) are used for prediction. Preliminary conceptualization of the catchment's hydrology shows that it is highly responsive to rainfall of high intensities, which are attributed to changes in land cover types; stream flow duration is also prolonged even in small tributaries, and this could be due to groundwater discharge from the fractured bedrock aquifer. The project forms part of a larger research study on participatory hydrological modelling, which involves stakeholder engagement in the selection of options being considered in the modeling process for sustainable water management.