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1 Altchenko, Yvan; Shu, Yunqiao. 2011. Water resource management in the Olifants Basin of South Africa: previous projects and future prospects. Paper presented at the 1st Sub Saharan Africa HELP Basin Workshop, Johannesburg, South Africa, 23-25 November 2011. 4p.

Water management ; River basin management ; Water stress ; Water quality ; Food security ; Research projects / South Africa / Olifants River Basin

(Location: IWMI HQ Call no: e-copy only Record No: H044604)

https://vlibrary.iwmi.org/pdf/H044604.pdf

(0.05 MB)

The Olifants River Basin is located in the north-eastern part of the South Africa and southern to Mozambique.The Olifants River passes through three provinces of South Africa (Gauteng, Mpumalanga, Limpopo Province), through the Kruger National Park, into Mozambique, where it joins the Limpopo . it is the home to nearly 10 % of the total population of South Africa. The climate is semi-arid, with rain falling primarily during the summer (November to March). Precipitation averages 630 mm and potential evaporation is 1700mm. In South Africa, significant mining, industrial and agricultural activities (including intensive irrigation schemes) are concentrated within the catchment, so it is of considerable importance for the country’s economy.However, Water is especially scarce in this basin. Like many river basins in South Africa, water resources in the Olifants river basin are almost fully allocated. Water demand management, especially in the agricultural sector, which is the biggest user, is one of the possible solutions being considered by the South African Department of Water Affairs and Forestry (DWAF). The basin also faces significant water quality problems, due to mining activities, industries, power generation and agricultural use of water. The impact of these pollutions (high salinity, high concentrations of metals, low pH) are probably multiple with serious ecological impacts. Particularly of concern in the downstream Kruger National Park which is a major tourist attraction in South Africa and more importantly very worrisome health impacts, since some people are drinking surface water without any treatment. In South Africa it is of prime importance to maintain a minimum level of water quality and quantity in the rivers in order to maintain a healthy biophysical environment (DWAF, 1997). This requirement, referred to as the ‘Ecological Reserve’, is as important in the South African legislation as meeting the basic human needs and must be met before any other users can abstract water. Main activities on the Olifants basin have been done through the Challenge Program on Water and Food and the WETwin project but not only.

2 Altchenko, Yvan; Villholth, Karen G. 2013. Transboundary aquifer mapping and management in Africa: a harmonised approach. Hydrogeology Journal, 21(7):1497-1517. [doi: https://doi.org/10.1007/s10040-013-1002-3]

Aquifers ; Mapping ; Groundwater management ; International waters ; River basins ; Lakes ; Legal aspects ; Corporate culture / Africa

(Location: IWMI HQ Call no: e-copy only Record No: H045995)

https://vlibrary.iwmi.org/pdf/H045995.pdf

(0.79 MB)

Recent attention to transboundary aquifers (TBAs) in Africa reflects the growing importance of these resources for development in the continent. However, relatively little research on these aquifers and their best management strategies has been published. This report recapitulates progress on mapping and management frameworks for TBAs in Africa. The world map on transboundary aquifers presented at the 6th World Water Forum in 2012 identified 71 TBA systems in Africa. This report presents an updated African TBA map including 80 shared aquifers and aquifer systems superimposed on 63 international river basins. Furthermore, it proposes a new nomenclature for the mapping based on three sub-regions, reflecting the leading regional development communities. The map shows that TBAs represent approximately 42 % of the continental area and 30 % of the population. Finally, a brief review of current international law, specific bi- or multilateral treaties, and TBA management practice in Africa reveals little documented international conflicts over TBAs. The existing or upcoming international river and lake basin organisations offer a harmonised institutional base for TBA management while alternative or supportive models involving the regional development communities are also required. The proposed map and geographical classification scheme for TBAs facilitates identification of options for joint institutional setups.

3 Altchenko, Yvan; Villholth, Karen G. 2014. Mapping irrigation potential from renewable groundwater in Africa – a quantitative hydrological approach. Hydrology and Earth System Sciences Discussions, 11(6):6065-6097.

Groundwater irrigation ; Groundwater recharge ; Water demand ; Water availability ; Water requirements ; Irrigation efficiency ; Water use ; Hydrology ; Environmental effects ; Farmland ; Farmer-led irrigation ; Living standards / Africa

(Location: IWMI HQ Call no: e-copy only Record No: H046504)

http://www.hydrol-earth-syst-sci-discuss.net/11/6065/2014/hessd-11-6065-2014-print.pdf
https://vlibrary.iwmi.org/pdf/H046504.pdf

(1.30 MB) (1.30 MB)

Groundwater provides an important buffer to climate variability in Africa. Yet groundwater irrigation contributes only a relatively little share of cultivated land, approximately 1% (about 2 million hectares) as compared to 14% in Asia. While groundwater is over-exploited for irrigation in many parts in Asia, previous assessments indicate an under-utilized potential in parts of Africa. As opposed to previous country-based estimates, this paper derives a continent-wide, distributed (0.5° spatial resolution) map of groundwater irrigation potential, indicated in terms of fractions of cropland potentially irrigable with renewable groundwater. The method builds on an annual groundwater balance approach using 41 years of data, allocating only that fraction of groundwater recharge that is in excess after satisfying other human needs and environmental requirements, while disregarding any socio-economic and physical constraints in access to the resource. Due to high uncertainty of groundwater environmental needs, three scenarios, leaving 30, 50 and 70% of recharge for the environment, were implemented. Current dominating crops and cropping rotations and associated irrigation requirements in a zonal approach were applied in order to convert recharge excess to potential irrigated cropland. Results show an inhomogeneously distributed groundwater irrigation potential across the continent, even within individual countries, reflecting recharge patterns and presence or absence of cultivated cropland. Results further show that average annual groundwater available for irrigation ranges from 692 to 1644 km3 depending on scenario. The total area of cropland irrigable with groundwater ranges from 27.2 to 64.3 million ha, corresponding to 12.5 to 29.6% of the cropland over the continent. The map is a first assessment that needs to be complimented with assessment of other factors, e.g. hydrogeological conditions, groundwater accessibility, soils, and socio-economic factors as well as more local assessments.

4 Altchenko, Yvan; Villholth, Karen G. 2015. Mapping irrigation potential from renewable groundwater in Africa – a quantitative hydrological approach. Hydrology and Earth System Sciences, 19(2):1055-1067. [doi: https://doi.org/10.5194/hess-19-1055-2015]

(Location: IWMI HQ Call no: e-copy only Record No: H046883)

http://www.hydrol-earth-syst-sci.net/19/1055/2015/hess-19-1055-2015.pdf
https://vlibrary.iwmi.org/pdf/H046883.pdf

(8 MB)

Groundwater provides an important buffer to climate variability in Africa. Yet, groundwater irrigation contributes only a relatively small share of cultivated land, approximately 1% (about 2 × 106 hectares) as compared to 14% in Asia. While groundwater is over-exploited for irrigation in many parts in Asia, previous assessments indicate an underutilized potential in parts of Africa. As opposed to previous country-based estimates, this paper derives a continent-wide, distributed (0.5° spatial resolution) map of groundwater irrigation potential, indicated in terms of fractions of cropland potentially irrigable with renewable groundwater. The method builds on an annual groundwater balance approach using 41 years of hydrological data, allocating only that fraction of groundwater recharge that is in excess after satisfying other present human needs and environmental requirements, while disregarding socio-economic and physical constraints in access to the resource. Due to high uncertainty of groundwater environmental needs, three scenarios, leaving 30, 50 and 70% of recharge for the environment, were implemented. Current dominating crops and cropping rotations and associated irrigation requirements in a zonal approach were applied in order to convert recharge excess to potential irrigated cropland. Results show an inhomogeneously distributed groundwater irrigation potential across the continent, even within individual countries, mainly reflecting recharge patterns and presence or absence of cultivated cropland. Results further show that average annual renewable groundwater availability for irrigation ranges from 692 to 1644 km3 depending on scenario. The total area of cropland irrigable with renewable groundwater ranges from 44.6 to 105.3 × 106 ha, corresponding to 20.5 to 48.6% of the cropland over the continent. In particular, significant potential exists in the semi-arid Sahel and eastern African regions which could support poverty alleviation if developed sustainably and equitably. The map is a first assessment that needs to be complimented with assessment of other factors, e.g. hydrogeological conditions, groundwater accessibility, soils, and socio-economic factors as well as more local assessments.

5 Cai, X.; Altchenko, Yvan; Chavula, G. 2017. Availability and use of water resources. In Lautze, Jonathan; Phiri, Z.; Smakhtin, Vladimir; Saruchera, D. (Eds.). 2017. The Zambezi River Basin: water and sustainable development. Oxon, UK: Routledge - Earthscan. pp.7-28. (Earthscan Series on Major River Basins of the World)

Water resources ; Water management ; Water availability ; Water use ; Water storage ; Water supply ; Water demand ; Surface water ; Domestic water ; Groundwater ; Dams ; Reservoir storage ; Climate change ; Economic aspects ; Investment ; Food security / Africa / Angola / Botswana / Malawi / Mozambique / Nambia / Tanzania / Zambia / Zambizi River Basin

(Location: IWMI HQ Call no: IWMI Record No: H048271)

6 McGill, B. M.; Altchenko, Yvan; Hamilton, S. K.; Kenabatho, P. K.; Sylvester, S. R.; Villholth, Karen G. 2019. Complex interactions between climate change, sanitation, and groundwater quality: a case study from Ramotswa, Botswana. Hydrogeology Journal, 27(3):997-1015. [doi: https://doi.org/10.1007/s10040-018-1901-4]

Climate change ; Sanitation ; Groundwater management ; Water quality ; Water supply ; Water security ; Drinking water ; Monitoring ; Wastewater treatment ; Water pollution ; Ecological factors ; Environmental factors ; Environmental protection ; Nitrates ; Denitrification ; Contamination ; Aquifers ; Rainfall ; Drought ; Pit latrines ; Faecal coliforms ; Caffeine ; Human wastes ; Case studies / Africa South of Sahara / Botswana / Ramotswa

(Location: IWMI HQ Call no: e-copy only Record No: H049051)

https://link.springer.com/content/pdf/10.1007%2Fs10040-018-1901-4.pdf
https://vlibrary.iwmi.org/pdf/H049051.pdf

(1.98 MB)

Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled human and natural system (CHANS) linking climate, sanitation, and groundwater quality in Ramotswa, a rapidly growing peri-urban area in the semi-arid southeastern Botswana, which relies on the transboundary Ramotswa aquifer for water supply. Analysis of long-term rainfall records indicated that droughts like the one in 2013–2016 are increasing in likelihood in the area due to climate change. Key informant interviews showed that due to the drought, people increasingly used pit latrines rather than flush toilets. Nitrate, fecal coliforms, and caffeine analyses of Ramotswa groundwater revealed that human waste leaching from pit latrines is the likely source of nitrate pollution. The results in conjunction indicate critical indirect linkages between climate change, sanitation, groundwater quality, and water security in the area. Improved sanitation, groundwater protection and remediation, and local water treatment would enhance reliable access to water, de-couple the community from reliance on surface water and associated water shortage risks, and help prevent transboundary tension over the shared aquifer.