Resource Directed Measures for Protection of Water Resources: Groundwater Component

WATER RESOURCES PROTECTION POLICY IMPLEMENTATION

RESOURCE DIRECTED MEASURES FOR PROTECTION OF WATER RESOURCES

SECTION F:PROCEDURE FOR THE COMPREHENSIVE DETERMINATION OF THE GROUNDWATER COMPONENT OF RDM

Senior Authors: H MacKay, Department of Water Affairs and Forestry

R Parsons, Parsons and Associates Specialist Groundwater Consultants

Version 1.0:

Date:24 September 1999

Section F:Comprehensive Determination of the Groundwater Component of RDM

F.1Status of method development

Development of tools to assess instream flow requirements of rivers was initiated almost a decade ago with significant progress having been made (Tharme, 1996; Tharme and King, 1998). In contrast, little attention has been paid to quantifying the role of groundwater in sustaining and supporting aquatic ecosystems. As a result, tools to determine the groundwater component of RDM were not readily available.

In developing procedures for implemention of Sections 13, 14, 16 and 17 of the National Water Act (Act 36 of 1998), development of tools to determine the groundwater component of RDM using the intermediate method (described in section E) was given priority. The Water Resources Situation Study initiated by the Department of Water Affairs and Forestry in 1998 provided a mechanism for developing tools for the Desktop and Rapid methods for determination of the groundwater component of RDM (described in Section C).

The Water Research Commission (WRC) and DWAF established a research programme in 1999 to support the development of tools required for quantifying the groundwater component of the Comprehensive RDM Determination (CRD) method. As the research is still in its early stages, no formal procedure is yet available for the groundwater component, but an early draft report has been released (Braune et al, 1999), which outlines various issues, considerations and possible approaches to comprehensive determination of the groundwater component of RDM.

Until such time as a formal comprehensive procedure is in place, the conceptual approach used in the IRD method presented in Section E should form the basis of a comprehensive determination of the groundwater component. It is the task of the responsible geohydrologist to ensure the requirements of a comprehensive determination are met as specified below.

F.2Requirements for Comprehensive Determination

The method for comprehensive determination of the groundwater component must allow the specification of a groundwater allocation according to section 23 of the NWA. It is the task of the responsible geohydrologist to demonstrate that the following aspects have been adequately provided for in determining the groundwater allocation:

  • water quantity and quality to meet the requirements of the Reserve for surface water ecosystems;
  • water quantity and quality to supply basic human needs;
  • protection of the integrity of the groundwater resource;
  • water to supply down-gradient or downstream needs.

The procedure used must:

  • be legally defensible, since assessments will form the basis for issuing legally valid water use licences;
  • be scientifically defensible and based on sound principles in line with the integrated ecosystem approach to water resource management;
  • match the Department’s administrative requirements for water use licensing;
  • provide a determination of the groundwater allocation which has a high to very high confidence level;
  • take approximately 8 to 12 months to provide the required information; and
  • be fully integrated with the other components of RDM (rivers, wetlands, estuaries), according to the procedures described in the Integrated Manual.

Where specific knowledge, information or expertise is lacking, a determination can be based on expert judgement applied within a structured and consistent process. All assumptions must be properly documented and fully justified. A formal, independent review process will be used to ensure quality control and consistency. Finally, the method used must accommodate the need for appropriate consultation with interested and affected parties, as specified by the National Water Act (Act No. 36 of 1998).

By definition, the CRD method may require extensive field data collection. At present, no formal guidelines are available in this regard. Data stored on the National Groundwater Database (NGDB) should form the basis for an assessment, but additional data needed to meet the specified level of confidence will have to be collected during the allowable timeframe.

Reference

Braune E, Xu Y, Van der Voort I, Conrad J, Colvin C, Le Maitre D, Van Tonder GJ, Chiang WH, Zhang J, Wright K, Hughes S & Pietersen K (1999). Comprehensive Determination of Water Resource Reserve: Groundwater Component (Zero Version). Water Research Commission Report, Programme K5/1007/0/1.

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Department of Water Affairs and Forestry, South Africa

Version 1.0 24 September 1999.