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T. A. Abiye and K. C. Leketa
upon which the community depends on for day-to-day activities. Therefore, recharge
rarely reaches water supply aquifers except in the shallow and weathered aquifers
with modern water. The increase in annual temperature from the Late Pleistocene to
the Holocene, and even in the recent times observed in this study, could encourage
policymakers and water managers to introduce integrated assessments of groundwater storage for resource allocation. Often, the extent of aquifer and storage for
water supply is not known and it can hinder sustainable management of the groundwater resource in the region. In many areas, well fields that have been supplying
water for big cities and irrigation schemes should also be accompanied by managed
aquifer recharge from available runoff and treated wastewater return into catchments.
In the Johannesburg region, on average, about 5 m
3 /s (Leketa and Abiye 2019) of
treated wastewater flows into streams from the wastewater treatment works. This
amount can be sustainably used to recharge the weathered and alluvial aquifers.
5 Conclusions
The integrated results from δ
18 O and
14 C records reveal an alarming temperature
variation over millennia within the southern African region that requires a thorough reflection on the management of the available groundwater resource. Through
geological times, temperature showed an increase based on the δ
18 O record that
has an impact on the availability of recharging water from rainfall. The results also
reveal the presence of historical groundwater in the region as a critical resource, especially because of the lack of active groundwater recharge, which is neither consistent nor reliable. So, in order to plan large-scale exploitation of groundwater that
was recharged over a thousand years ago, a contingency plan to include managed
aquifer recharge through runoff harvesting, treated wastewater storage and use of
water-efficient irrigation technologies, must be designed.
References
Abiye TA (ed) (2013a) The use of isotope hydrology to characterize and assess water resources in
Southern Africa. WRC Report No TT 570/13, Pretoria, p 211. ISBN 978-1-4312-0480-9
Abiye TA (2013b) Surface water and groundwater interaction in the upper Crocodile River basin.
In: Abiye T (ed) The use of isotope hydrology to characterize and assess water resources in South
(ern) Africa. WRC Report No TT 570/13, Pretoria, pp 141–164. ISBN 978-1-4312-0480-9
Abiye TA (2016) Synthesis on groundwater recharge in Southern Africa: A supporting tool for
groundwater users. Groundwater Sustain Dev 2:182–189
Abiye TA, Mengistu H, Demlie MB (2011) Groundwater resource in the crystalline rocks of the
Johannesburg area, South Africa. J Water Resour Protect 03:199–212
Abiye TA, Mengistu H, Masindi K, Demlie MB (2015) Surface water and groundwater interaction in
the upper Crocodile River Basin, Johannesburg, South Africa: Environmental Isotope Approach.
South Afr J Geol 118(2):109–118
T. A. Abiye and K. C. Leketa
upon which the community depends on for day-to-day activities. Therefore, recharge
rarely reaches water supply aquifers except in the shallow and weathered aquifers
with modern water. The increase in annual temperature from the Late Pleistocene to
the Holocene, and even in the recent times observed in this study, could encourage
policymakers and water managers to introduce integrated assessments of groundwater storage for resource allocation. Often, the extent of aquifer and storage for
water supply is not known and it can hinder sustainable management of the groundwater resource in the region. In many areas, well fields that have been supplying
water for big cities and irrigation schemes should also be accompanied by managed
aquifer recharge from available runoff and treated wastewater return into catchments.
In the Johannesburg region, on average, about 5 m
3 /s (Leketa and Abiye 2019) of
treated wastewater flows into streams from the wastewater treatment works. This
amount can be sustainably used to recharge the weathered and alluvial aquifers.
5 Conclusions
The integrated results from δ
18 O and
14 C records reveal an alarming temperature
variation over millennia within the southern African region that requires a thorough reflection on the management of the available groundwater resource. Through
geological times, temperature showed an increase based on the δ
18 O record that
has an impact on the availability of recharging water from rainfall. The results also
reveal the presence of historical groundwater in the region as a critical resource, especially because of the lack of active groundwater recharge, which is neither consistent nor reliable. So, in order to plan large-scale exploitation of groundwater that
was recharged over a thousand years ago, a contingency plan to include managed
aquifer recharge through runoff harvesting, treated wastewater storage and use of
water-efficient irrigation technologies, must be designed.
References
Abiye TA (ed) (2013a) The use of isotope hydrology to characterize and assess water resources in
Southern Africa. WRC Report No TT 570/13, Pretoria, p 211. ISBN 978-1-4312-0480-9
Abiye TA (2013b) Surface water and groundwater interaction in the upper Crocodile River basin.
In: Abiye T (ed) The use of isotope hydrology to characterize and assess water resources in South
(ern) Africa. WRC Report No TT 570/13, Pretoria, pp 141–164. ISBN 978-1-4312-0480-9
Abiye TA (2016) Synthesis on groundwater recharge in Southern Africa: A supporting tool for
groundwater users. Groundwater Sustain Dev 2:182–189
Abiye TA, Mengistu H, Demlie MB (2011) Groundwater resource in the crystalline rocks of the
Johannesburg area, South Africa. J Water Resour Protect 03:199–212
Abiye TA, Mengistu H, Masindi K, Demlie MB (2015) Surface water and groundwater interaction in
the upper Crocodile River Basin, Johannesburg, South Africa: Environmental Isotope Approach.
South Afr J Geol 118(2):109–118