Potential impacts of climate change on groundwater recharge in South Africa using stable isotopes of water
Date
2021-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Unimodal wet season precipitation plays a significant role in ensuring sustainable and
continuous replenishment of groundwater resources, especially in arid to semi-arid climates that
only recharge during these seasons in heavy rainfall events. Therefore, changes in
precipitation patterns (i.e., the frequency, intensity, and duration of precipitation events) may
effectively threaten the reliability and sustainability of groundwater resources. This
study investigates the relationship between stable water isotope composition of groundwater and
precipitation samples collected across the different climatic zones in South Africa. The
analysis was done to deduce the evaporative conditions experienced by precipitation before
groundwater recharge, which in turn assisted in extrapolating how various changes in climatic
conditions would translate to groundwater recharge (e.g., induced evaporative loss of rainfall).
Both precipitation and groundwater samples showed a proper alignment with the Global
Meteoric Water Line (GMWL) and respective LMWLs with a dispersion that increased from the O- and H-
isotope depleted sections towards the enriched areas. Groundwater samples showed relative
characteristics with wet season precipitation plotting along the same regionality on
respective Local Meteoric Water Lines (LWMLs). The secondary evaporation of precipitation, noted by
the deviation of groundwater samples from the GMWL and respective LMWLs, increased from the
south-western and east coasts, which receive relatively higher precipitation amounts towards the
interior, south, and west coast of the country, which are somewhat dryer. This analysis will assist
in the forecasting of future groundwater recharge patterns in response to climate change.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
Description
Thesis (MSc)--Stellenbosch University, 2021.
Keywords
Groundwater recharge -- South Africa, Stable isotope tracers, Groundwater -- Climatic factors, Arid regions -- Environmental aspects -- South Africa, Temperature -- Seasonal variations, UCTD