*3.2.1 Spatial changes in groundwater resources of the STAS*

Similar to the KSTA, the STAS is also large; thus, changes in groundwater storage will not be uniform throughout the entire surface area of the aquifer. The spatial changes that occurred in the Stampriet (STAS) are depicted in **Figure 12**, showing how the depth of groundwater in the aquifer changed over time.

Areas that increased in depth as well as areas where depth was reduced are depicted across the aquifer. Although **Figure 12** shows that large parts (approximately *Groundwater Dynamics in Transboundary Aquifers of Southern Africa DOI: http://dx.doi.org/10.5772/intechopen.109906*

**Figure 12.** *Spatial changes in the groundwater storage of the Stampriet TBA.*

90%) of the aquifer experienced a decline in storage depth between 1978 and 1987, areas of recharge increased between 1988 and 2007. During the first decade of study (1948–1957), the Stampriet was dominated by areas of recharge (0.1–50 cm increase in depth), with a small portion of the aquifer showing points of discharge (−24.1 to 0.1 cm decrease in depth) nested along the border of Botswana and South Africa (**Figure 12**). In the next decade (1958–1967), areas of discharge increased and included parts of the aquifer underlying Namibia. The largest positive change in storage depth (increase in depth) occurred between 1968 and 1977, with large areas of the aquifer experiencing increased depth, and only a small part of the aquifer experiencing a minimal decrease in depth. The greatest loss in storage in the Stampriet were recorded between 1978 and 1987, where only a small portion of the aquifer recorded an increase in depth, whereas the remaining parts of the aquifer experienced a loss in depth. Some areas of the aquifer recorded losses of 50 cm and above, with some areas also recording losses above 100 cm. A period of recovery was documented between 1988 and 1997 in Namibia, where the majority of the aquifer's surface area depicted an increase in depth, whereas decreasing depths were observed in parts of the aquifer underlying Botswana, South Africa as well as some parts of southwestern Namibia. Although there were periods when the Stampriet recorded large reduction in depth (1978–1987), the overall positive change in depths reflects increased recharge. The two aquifers mentioned above have experienced fluctuations in groundwater depth and volume over the 72-year study period. Both the aquifers experienced an increase in depth between 1968 and 1977, whereas the largest losses were recorded in both aquifers between 1978 and 1987.

#### **3.3 Conservation, development and management of the KSTA and the STAS**

The governments of the Republic of Botswana, the Kingdom of Lesotho, the Republic of Namibia and the Republic of South Africa established the Orange-Senqu River Commission Agreement (ORASECOM agreement) on 3 November, 2000 [55]. The agreement was founded on the Helsinki Rules [56], the UN Watercourses

Convention [57] as well as the revised SADC protocol on shared water resources [58], with the aim of serving as technical advisor to the parties on matters relating to the development, utilisation and conservation of the water resources of the Orange-Senqu Basin [55].

The ORASECOM agreement lists cooperation as the first obligation of the parties, as stipulated in article 7(1) of the agreement. The obligation to cooperate is an important provision, as it makes it possible for member states to jointly develop, conserve and govern their shared water resources in order to achieve mutual benefit. In addition to the obligation to cooperate, the ORASECOM agreement imposes on member states a duty to protect and preserve the ecosystem of the Orange-Senqu watercourse, article 7(12) of the agreement also imposes a duty on member states to individually and jointly take all the relevant measures to protect and preserve the river system from its sources and headwaters to its common terminus, and article 5(2)(6) imposes a duty to control and reduce pollution. Article 7(2) of the agreement further imposes a duty on watercourse states to utilise the resources of the transboundary catchment in an equitable and reasonable manner in line with the 2000 revised SADC protocol, with a view to attaining an optimal and sustainable use of the resource, in order to ensure its protection.

Member states are further instructed to take all suitable actions to avoid the causing of significant transboundary harm to any other party in line with the revised SADC protocol. The ORASECOM agreement further imposes on member states a duty to include an environmental impact assessment (EIA) study as part of their due diligence and to also address the possible effects of any planned activity on the social, cultural, economic as well as the natural environment. Reflecting the 1997 watercourses convention, as well as the 2000 revised SADC protocol, the ORASECOM agreement also stipulates in articles (7(5-11, and 16) the rules and procedures to be followed by member states in planning and implementing activities (within their territories), which might have adverse effects on the shared watercourse or on other member states.

The ORASECOM agreement established the commission on the Orange-Senqu Basin. Through cooperation, the commission is able to protect and manage their shared water resources in an equitable and sustainable manner with the consideration of each member state's interest in the shared resource. In addition to the legal status of the commission stipulated in the first article of the agreement, the agreement also makes provision for member states to establish river commissions with regard to any part of the Orange-Senqu (article 1(4) and further states that such agreements will be subordinate to the ORASECOM agreement. Furthermore, the agreement makes provision for the establishment of joint commissions and committees on the protection, conservation, development and governance of their respective watercourses. As a result, the ORASECOM established the Groundwater Hydrology Committee (GWHC), which is responsible for all the groundwater-related matters of the Orange-Senqu Catchment (ORASECOM, 2021), thus making provision for the protection and governance of shared groundwater resources through the joint committees of cooperation.

In May 2017, ORASECOM's Groundwater Hydrology Committee (GWHC) as well as the Technical Task Team (TTT) supported the proposal to establish within the ORASECOM structure a multi-country cooperation mechanism (MCCM) for the governance and management of the Stampriet Transboundary Aquifer System [59]. The MCCM is meant to facilitate cooperation among states in the development, monitoring, governance and management of the STAS [59, 60]. The cooperation mechanism

#### *Groundwater Dynamics in Transboundary Aquifers of Southern Africa DOI: http://dx.doi.org/10.5772/intechopen.109906*

was established as part of the STAS-Governance of Groundwater Resources in Transboundary Aquifers (GGRETA) Project with the aim of the mechanism becoming a joint mechanism advising member states on the management of the STAS [59].

The results of the study show that there is great spatio-temporal variability in the groundwater resources within the two transboundary aquifers shared by South Africa and its neighbouring countries. Moreover, the seasonal variability in groundwater resources in the two transboundary aquifers is in line with findings from previous studies that found that groundwater variability is largely influenced by climatic variations [61–66], predominantly precipitation [67, 68], as well as evapotranspiration [69, 70]. Moreover, as shown in previous studies [18, 45, 61, 71–81], data acquired through remote sensing techniques can be exceptionally applicable in hydrogeological studies where *in situ* data are insufficient. Furthermore, in addition to the ORASECOM Groundwater Hydrology Committee, the cooperation mechanism mentioned above is the first governance mechanism to ever be incorporated in a river basin organisation, making it possible for the commission to manage the water resources of the Orange-Senqu conjunctively, following Integrated Water Resources Management (IWRM) processes.

Since only six international agreements and arrangements have been concluded1 on the utilisation, sound management and governance of over 400 transboundary aquifers globally, compared to over 3600 agreements and arrangements that have been signed on the 279 shared surface waters [82], the law regulating transboundary groundwater resources is, thus, gravely lagging and, as such, still in its initial stages. Therefore, through the establishment of joint commissions such as the multi-country cooperation mechanism responsible for the development and management of the STAS, the equitable use and sustainable management of transboundary groundwater resources is possible not only in South Africa, but globally too.

The study has shown that incorporating the management of groundwater resources through the establishment of groundwater specific committees within existing surface water agreements can ensure the protection, as well as manage equitable and sustainable utilisation of shared groundwater resources.
