Investigating a spatial approach to groundwater quantity management using radius of influence with a case study of South Africa

Abstract

The purpose of this paper is to investigate whether a simple, spatially-based approach to groundwater sustainability using radius of influence should be used to replace the pervasive, yet deprecated, 'natural recharge water balance' volumetric method. Using South Africa as a case study, the radius of influence methodology was shown to be scientifically practical, to provide plausible results, and to be permissible under the country's water laws. The approach also provides better indicators for institutions involved in groundwater management, and remains conceptually correct at all scales. However, further research is recommended on more robust alternatives to the Cooper-Jacob equation for determining radius of influence.

Implementation of groundwater protection measures, particularly resource-directed measures in South Africa: a review paper

“…Simpler, spatially-based approaches (as an alternative to the recharge balance approach) are available to enable practical protection, which have not been applied to date. A radius of influence methodology was shown to be scientifically practical to provide plausible results and to be permissible under the country's water law (Seward et al, 2015). The RDM process takes into account inputs by stakeholders.…”

The Water Budget Myth and Its Recharge Controversy: Linear vs. Nonlinear Models

“…This implies the left‐hand side of Equation 31 is zero, from which the following well‐known formula can be derived: $$$$ Q= N\pi {r}_d^2 $$$$ Equation 34 is used to calculate the radius of the capture zone (Haitjema 1995), also called the area contributing recharge to the well (Reilly and Pollock 1996). Note that this “capture” may not be confused with the water budget capture (Seward et al 2015; Barlow et al 2018). Since $$$ {h}_2 $$$ is zero in this case, by definition, $$$ {r}_d $$$ is also the radius of influence.…”

“…Seward et al (2015) question Zhou's (2009) statement that aquifer sustainability depends on both natural recharge and capture, as the first is missing in Bredehoeft's (2002) capture equation. Seward et al (2015) also believe a large part of the hydrogeological community see no harm in “pumping the recharge” approaches to sustainability, referring to Balleau (2013), although the latter suggests to abandon the traditional concept of safe yield from the administrative functions, as the concept was dismissed by groundwater experts long time ago. Balleau (2013) even disapproves the use of a ratio of natural recharge to well‐field withdrawals as indicator of sustainability by Wada et al (2010).…”

Review: karst springs in Shanxi, China

“…There is a certain gap between local and international investigators regarding the methods used. For instance, on the basis of summarizing the situation of groundwater management in South Africa, Seward et al (2015) proposed a simple method of influence radius to be added to the water balance approach to carry out groundwater protection, which is aimed to supplement the existing practice of groundwater management, and to ensure the sustainability of groundwater, but further work is needed for the protection and management of karst water in Shanxi spring catchments.…”

“…8. With the development of the economy in Shanxi spring catchments and the improvement of the people's consciousness of environmental protection, research on the analysis of karst spring protection, sustainable management of karst water, and water ecological environment of coal mine areas in spring catchments are also problems to be strengthened in the future (Seward et al 2006(Seward et al , 2015. 9.…”