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Managed Aquifer Recharge: Southern Africa

Book Cover for Managed Aquifer Recharge: Southern Africa

Publication year: 2021
Number of pages: 96
ISBN: 978-1-77470-006-8
https://doi.org/10.21083/978-1-77470-006-8

Authors:
Eberhard BrauneUniversity of Western Cape, South Africa

Sumaya Israel – University of Western Cape, South Africa

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Updated: 2 May 2022

Book Description

Key to the African water crisis, often referred to in international forums, is the large spatial and temporal variability of resource availability, the arid climate prevalent in about 60% of the African continent, and the widespread lack of skilled and experienced human resources to manage the irregular availability of water. Provision of sufficient storage capacity under growing water demand and increasing climate variability is one of the main concerns for water managers in the region in the coming decades. The natural storage in aquifers makes conjunctive use of water resources and artificial recharge of aquifers particularly attractive in the region.

Excellent progress has been made with all knowledge-related aspects and promotion of artificial recharge in South Africa. This has been driven by the Water Research Commission, with its research and development programmes, for nearly fifty years now. Among other projects, it led to the construction of a major borehole injection scheme for the City of Windhoek, Namibia. Windhoek’s MAR (managed aquifer recharge) scheme is of particular interest because it involves large-scale borehole injection and recovery in a highly complex, fractured quartzite aquifer. Implementation in South Africa was helped by the detailed Artificial Recharge Strategy developed by the national Department of Water Affairs and Forestry. With 17 reported cases, South Africa has by far the highest MAR implementation in Africa.

With this as background, six cases are discussed, covering different physical and management environments and recharge methods in southern Africa. They are structured to bring out an understanding of the different driving forces towards the use of MAR techniques, factors that affect the selection of a particular MAR technique, and how efficient and effective various MAR techniques have proven to be.

The main stumbling block to a much greater, systematic roll-out of this technology has been a lack of appropriate governance and institutional development for the sustainable utilisation and management of groundwater resources in South Africa. This has been a failing in Africa in general, despite groundwater’s strategic role as an essential resource to help achieve community development and poverty alleviation.

Contents

1 INTRODUCTION

2 HISTORY OF MANAGED AQUIFER RECHARGE IN SOUTHERN AFRICA

2.1 Main Learning Outcomes

2.2 Water Availability in Southern Africa

2.3 Groundwater Resources in Southern Africa

2.4 Increased Demand for Groundwater Resources

2.5 Traditional Water Conservation Techniques

2.6 Modern Managed Aquifer Recharge in Southern Africa

2.7 Selection of Case Studies

3 CASE STUDY: ATLANTIS, CAPE TOWN SOUTH AFRICA

3.1 The Need for Artificial Recharge – Setting the Scene

3.2 The Source Water

3.3 Aquifer Hydraulics

3.4 Water Quality

Pollution
Water Quality Improvement and its Monitoring

3.5 Scheme Elements

3.6 Water Resource Management Environment

3.7 Evaluation and Way Ahead

4 CASE STUDY: OMARURU DELTA, WEST COAST, NAMIBIA

4.1 The Need for Artificial Recharge – Setting the Scene

4.2 The Source Water

Sand Rivers

4.3 Aquifer Hydraulics

4.4 Water Quality

4.5 Scheme Elements

4.6 Water Resource Management Environment

Water Supply Institutional Approach

4.7 Evaluation and Way Ahead

5 CASE STUDY: LANGEBAAN, WEST COAST, SOUTH AFRICA

5.1 The Need for Artificial Recharge- Setting the Scene

Water Resources Planning Leads to MAR

5.2 The Source Water

5.3 Aquifer Hydraulics

5.4 Water Quality

5.5 Scheme Elements

Selection of Sites for Recharge

5.6 Water Resource Management Environment

Achieving Stakeholder Engagement

5.7 Evaluation and Way Forward

A Phased Implementation Approach

6 CASE STUDY: WINDHOEK, NAMIBIA

6.1 The Need for Artificial Recharge – Setting the Scene

Augmentation Options in a Water-Scarce Country
The MAR Opportunity

6.2 Aquifer Hydraulics

Favorable Conditions in Hard-Rock Aquifer
Over-Abstraction from Aquifer Storage

6.3 The Source Water

6.4 Water Quality

Guiding Principles for Quality of Water Directly Injected into Aquifer
Special Water Quality Concerns Associated with the Borehole Injection

6.5 Scheme Elements

Benefits of Windhoek MAR Scheme

6.6 Water Resource Management Environment

Finance Model for the MAR Scheme

6.7 Evaluation and Way Ahead

7 CASE STUDY: KHARKAMS, SEMI-ARID INTERIOR, SOUTH AFRICA

7.1 The Need for Artificial Recharge – Setting the Scene

7.2 The Source Water

Small-Scale Water Supply in a Semi-Arid Area

7.3 Aquifer Hydraulics

7.4 Water Quality

7.5 Scheme Elements

7.6 Water Resource Management Environment

7.7 Evaluation and Way Ahead

8 CASE STUDY: PLETTENBERG BAY, SOUTHERN CAPE, SOUTH AFRICA

8.1 The Need for Artificial Recharge- Setting the Scene

8.2 The Source Water

8.3 Aquifer Hydraulics

MAR Considerations in a Fractured Aquifer

8.4 Water Quality

Dissolved Iron and Borehole Clogging

8.5 Scheme Elements

MAR Cost Comparison with Desalination

8.6 Water Resource Management Environment

8.7 Evaluation and Way Forward

9 MAR AS PART OF SUSTAINABLE GROUNDWATER RESOURCE DEVELOPMENT

9.1 Some Experience with MAR Success Factors

Technical Issues Required for a Successful MAR Implementation

9.2 Roll-Out of the Artificial Recharge Strategy

9.3 Institutional Shortcomings: The Cape Flats Aquifer Case

MAR and Increasing Urbanization

10 CONCLUSION

Way Forward Towards Good Groundwater Governance

11 EXERCISES

Exercise 1
Exercise 2
Exercise 3

12 REFERENCES

13 EXERCISE SOLUTIONS

Solution Exercise 1
Solution Exercise 2
Solution Exercise 3

14 ABOUT THE AUTHORS

Interview with Authors