Eddie Riddell & Robin Petersen With acknowledgment to: Managing Transboundary Aquifers: the role of large protected area management with a focus on the Limpopo TBA Midzi Eddie Riddell & Robin Petersen With acknowledgment to: WH du Toit (DWS) H Verster (DWS) & team eddie.riddell@sanparks.org Water Resources Management, Conservation Management, Kruger National Park

Limpopo Transboundary Aquifer (TBA) Makuleke Ramsar Wetlands of International Importance Republics of: Mozambique South Africa Zimbabwe

The Limpopo River Aquifer Cobbing et al, 2008 Natural unconsolidated alluvial deposits Wet season runoff recharges alluvial aquifer, SW decline in dry winter (dislocated pools connected by sub-surface flows) TBA broadest as it enters Mozambique ~700 m. T = 420 m2 /d. Good groundwater quality - around 200 mS/m RSA largest agricultural use of water from this aquifer (dereliction of irrigation farms in Zimbabwe) - Mzingwane catchment CGIAR Challenge programs Hypothetical storage of 150 Mm3 Limpopo TBA The Limpopo River Aquifer Cobbing et al, 2008 Limpopo River is characterised by wet season runoff recharges the alluvial aquifer, SW declines during dry winter reducing to dislocated pools of standing water connected by sub-surface flows. The larger pools hold water for extended periods of time - often spanning more than one dry season - confirming their sub- surface hydraulic continuity. Rock outcrops or shallow bedrock in the river channel act as natural impounding structures; water collects behind these structures and can be abstracted by surface Pumps Assuming conservative values of 20 % for effective porosity, 100 m for channel width and 10 m for saturated thickness, this yields a hypothetical storage of 150 Mm 3 for this reach. This volume reduces to 105 Mm 3 at the 70 % exploitation limit, which makes the resource equivalent to an impoundment with a volume in the top 8 % of surface water impoundments in South Africa. More significantly, this figure suggests that the water demand of 5 900 ha of irrigated land - shared between the riparian countries – could be met from this resource. Thus the aquifer is a potentially valuable water source for resource-poor farmers, able to meet and sustain small scale irrigation demands even during dry periods when surface flow ceases.

Limpopo TBA No Monitoring!! Active Monitoring Active Monitoring Du Toit & Verster, 2017 DWA, 2014 DWA, 2014 DWA, 2014 No Monitoring!! Active Monitoring Active Monitoring Note Limp, Luv and Shi GW monitoring areas

Rain Intensity >150mm/day-1 Limpopo TBA: Luvuvhu/Limpopo Observations: GW recharge during 1:100 – 1:200 year events Luvuvhu GMA Shingwedzi GMA The LEV: GMA shows a strong declining trend in water levels since 2007 up to 2013. A recharge event in 2013 raised the water level a few meters and was maintained at the higher level till end 2014 when water levels dropped again. Water levels in the GMA: SHI shows an overall declining trend despite some minor recharge events that are noticeable on almost all of the graphs. However, a major recharge event in January 2013 changed the situation and terminated the tendency in many cases. As expected the declining tendency (this is not referring to the seasonal fluctuations within a single hydrological year) has again manifested itself in some boreholes after the January 2013 event. The post January 2013 declining tendency is, however, at a much slower rate compared to pre-January 2013 period (Figure 18). Rain Intensity >150mm/day-1

Limpopo TBA: Shingwedzi – Groundwater Dependent Ecosystem & NFEPA Artesian Springs Colvin et al, 2011 Aquifers integral part of savanna landscapes – alluvial, weathered basalt, granitic lineaments Discharge patterns = ecological expression GW bioavailable & hydrological heterogeneity Large store of water in a seasonally dry landscape = perennial lushness and productivity GDEs are refuge habitats & nutrient hot-spots

Limpopo TBA: Population Dependence Esme-Four Farm Ian van Brouwershaven High GW Dependency DWA, 2014 Safe Nitrate Levels DWA, 2014 M McHale

Floodplain Interaction Resource Dependency in certain sections Limpopo TBA: Summary Critical Gaps Floodplain Interaction Resource Dependency in certain sections Groundwater Dependent Ecosystems Downstream Requirements Protected Area Expansion Strategy EGS & SWSA Resource Dependency better understood in SA context

New SWSAs