Can groundwater be successfully implemented as a bulk water resource within rural Limpopo Province? Analysis based on GRIP datasets

Can groundwater be successfully implemented as a bulk water resource within rural Limpopo Province? Analysis based on GRIP datasets Willem du Toit1*, Martin Holland2, Reinhardt Weidemann3 and Fanie Botha4 Department of Water Affairs, PO Box 118, Polokwane, 0700, South Africa 2 Deltah, PO Box 6662, Woodhill, 0076, South Africa 3 VSA Leboa Consulting (Pty) Ltd, PO Box 222, Polokwane, 0700, South Africa 4 Private Consultant, PO Box 11640, Hatfield, 0028, South Africa 1 Abstract Groundwater is a strategic water resource in rural Limpopo Province and it accounts for almost 70% of rural domestic water supply. The resource is available throughout the Province in varying quantities and qualities depending on the hydrogeological properties of the underlying aquifer. These properties are mostly secondary in nature and are constrained by the processes of weathering, faulting, fracturing and the influence of intrusive rocks. These properties define typical fractured aquifers in which the selection of drilling sites requires a thorough scientific approach to locate a successful productive borehole. While most water service authorities in the Province have been randomly developing new boreholes with limited success rates, the analysis of datasets in the newly established groundwater data repository, the Limpopo Groundwater Resource Information Project (GRIP) demonstrates that large quantities of groundwater can be obtained and used for bulk supply if the drilling sites are scientifically selected. The GRIP dataset contains 24 922 entries of which 4 000 were tested. The pumping test results indicate that an estimated 576 000 m3/d (210 Mm3/a) can be sustainably abstracted from boreholes in approximately 2 500 villages that are dispersed throughout the Province. However, more than 50% of these boreholes are unequipped of which 3 000 can provide a combined yield of 109 Mm 3/a based on a 24 h abstraction rate. These results show that groundwater can be developed as a potential viable bulk-water supply source. This paper attempts to demonstrate, using the existing GRIP dataset, that groundwater is an underutilised resource that can be viably and cost-effectively developed as an alternative bulk water source or conjunctively with surface water. Keywords: groundwater, GRIP, bulk water supply, information variability, borehole productivity, conjunctive use, well-field development cost, well-field yield Introduction Historically, groundwater has always been seen as a standalone or site-specific resource and never as regional bulk-water supply. Only as recently as 1998, with the promulgation of the National Water Act (Act No. 36 of 1998; RSA, 1998), groundwater became part of an integrated water resource; before that boreholes were mostly owned and managed by landowners. This article aims to indicate how groundwater can be rapidly and cost-effectively developed as a bulk-water resource, meeting short- to medium-term water requirements, becoming part of a truly integrated water resource. In the National Water Resource Strategy (NWRS), groundwater was not introduced as an exciting nor strategic resource, but rather pushed as a suitable resource for hand-pump installations, emergency water supply or rural use in small communities (DWAF, 2004). However, in the publication ‘Strategic Planning for Water Resources in South Africa Situation Analysis’ (DWA, 2009) the Department of Water Affairs (DWA) concurred that groundwater can play a significant role in larger cities/towns, for example Cape Town. Therefore, at a policy level, groundwater has come a long way and it seems that South Africa’s groundwater has a bright future. This paper was originally presented at the International Conference on Groundwater: Our Source of Security in an Uncertain Future, Pretoria, 19-21 September 2011. * To whom all correspondence should be addressed.  +27 82 808-6386; e-mail: Groundwater as a water resource has a competitive advantage, especially within the short- to medium-term solution sphere; this so-called advantage can broadly be divided into 3 major aspects: • Conjunctive resource: It can be used as an additional water resource together with surface water to meet water demands. • Rapid development: High-yielding aquifers are quite common in South Africa and as a result they can be developed at or close to the user within a short space of time. • Phased development: When developing a surface water resource, future demands need to be considered; as a result massive capital expenditure is required, for infrastructure which will only be used within the next 20 years to 30 years, whereas groundwater resources can be developed as the need arises. Nevertheless, groundwater still struggles to find a path from being a scientific entity to becoming a useable water resource. As a result, the endeavour to have groundwater take its rightful place as a conjunctive water resource continues to fail. This disbelief and lack of confidence in the resource, despite the scientific evidence available within South Africa, has been created as a result of 3 specific reasons, as discussed below. The most common question is, why not jump in and start to develop groundwater resources? If a village experiences a water shortage, boreholes are drilled, tested and equipped. This practice results in scattered, single-source, poorly-maintained water resources. This is clearly illustrated when boreholes are selected for pump testing using exactly the same approach, regardless of context, e.g. in the GRIP study areas there are http://dx.doi.org/10.4314/wsa.v38i3.4 Available on website http://www.wrc.org.za ISSN 0378-4738 (Print) = Water SA Vol. 38 No. 3 International Conference on Groundwater Special Edition 2012 ISSN 1816-7950 (On-line) = Water SA Vol. 38 No. 3 International Conference on Groundwater Special Edition 2012 391 hardly places where a non-tested borehole cannot be found within a kilometre. However, GRIP results (GRIP Limpopo Online) suggest that as much as 75% of rural Limpopo can be supplied with potable water during a drought period by simply repairing vandalised or dysfunctional boreholes (Botha, 2005). Why the lack of confidence in the available groundwater figures? Certainly, one answer is that groundwater was the ‘new kid on the block’ and in the beginning there was large variability in different groundwater figures and that created discomfort in groundwater development. According to the NWRS (DWAF, 2004), the total available yield from groundwater resources in South Africa is estimated at about a 1 000 Mm3/a. Based on Vegter’s (2001) estimation of current use of groundwater due to the development of the modern drilling rig, the use should be around 3 600 Mm3/a, corresponding well with the figure determined by Baron et al. (1996). If Baron et al. and Vegter are correct in their assumptions, then use exceeds the NWRS figure threefold. The different figures between use and yield create uncertainty. Confusing the issue (...truncated)