By Mary Seely, Desert Research Foundation of Namibia
When people first hear the word ‘conservation’ they think of wildlife, desert elephants or perhaps our exotic landscapes. But underlying conservation in this sense are the ecological services such as water and soil that are key ingredients, not only for wildlife but also for people. One major figure in this regard is Ben van der Merwe, a water engineer of renown who has contributed to establishing the water supply system that we enjoy without giving it a second thought.
Recycling of waste water into Windhoek’s domestic water supply is one of the areas where Ben has played a major role. This ground-breaking approach to augmenting Windhoek’s scarce water resources, initiated by the early pioneers in direct water reuse in the 1960s, represents the very first such system in the world. By the 1980s the plant had proved its worth but was too small and techniques had changed. As Water Engineer for the City of Windhoek, Ben was the driving force behind the construction of the new Goreangab Water Reclamation Plant to improve the process and increase the capacity from 7 600 m3 per day to 21 000 m3 per day. The Goreangab Plant is able to provide approximately 32% of the daily water demand of Windhoek. This represents 7.5 million cubic metres of water per annum (at full production) that do not have to come from some distant part of Namibia. This also represents conservation of a resource that is key to Namibia’s environment in its truest sense.
During the 1990s Ben, with support from local users (such as the Golf Club and schools), initiated the installation of a dual-pipe system in Windhoek to provide purified sewage effluent for irrigation. The dual-pipe system was completed in 1993 and substituted about 6% of high-quality water with irrigation water at approximately 25% of the cost of potable supply to consumers in Windhoek. The availability of cheaper irrigation water stimulated the development of sports fields and parks in Windhoek, especially in previously neglected areas. The Shell Environmental Award was awarded for this project in 1993.
In 1992, when Water Demand Management (WDM), a critical aspect of Integrated Water Resources Management, was only starting to be discussed globally, Ben was already involved in water recycling and the implementation of WDM principles in Windhoek. Since 1994 an integrated WDM strategy has been implemented. This includes technical aspects, regulation, public campaigns, policy changes and the introduction of rising tariffs to reduce excessive water demand. Ben was a pioneer of rising tariffs, where people who use smaller amounts (mostly low-income families) pay a low rate but those who use more water pay higher rates. This helps people to prevent wastage, save money and conserve our scarce water resources. In 1998 this earned the project another Shell Environmental Award. The implementation of WDM lowered the annual growth in water demand to less than 3%, despite the population and economic growth rate, and decreased the expected water demand by more than 25% in 2005.
Even more innovative is the process of artificial recharge of Windhoek’s main aquifer in the southern part of the city. Ben identified the potential for future water augmentation through artificial recharge, which is based on the premise that surface water is more efficiently stored underground in an aquifer, and can be used during water shortages. Instead of using a borehole to withdraw water from beneath the ground, the borehole is used to inject water into the aquifer to create an underground water bank. By doing this on a large scale, several years’ supply (approximately three years) can be stored in the ‘water bank’, which is not lost to evaporation, and is available when rainfall is low and surface water scarce.
In several international studies and a recent study funded by NamWater, the scheme was identified as the next and best water-supply option for the Central Area of Namibia. Dr Peter Dillon, Chairman of the International Association of Hydrologists, Commission on the Managing of Artificial Recharge, declared that the Windhoek Artificial Recharge Scheme would ‘stand out as an internationally acclaimed demonstration of artificial recharge’.
While having focused on Windhoek for many years, Ben – in his independent capacity since 1998 – is now applying his unique vision to other centres in Namibia. Several years ago the town of Rehoboth was about to have its water supply cut off for non-payment of its water account. Ben, working with the town officials and councillors, helped turn the situation around so that fixing of system leakage, replacement of water meters, appropriate tariff structures, improved billing systems and information dissemination about water use and payment in Rehoboth were implemented. People are now paying their bills on time and are paying back the arrears, thus placing the town on a sustainable basis in terms of water supply and system management.
Conservation in Namibia has many facets and Ben van der Merwe, with his numerous innovative contributions to sustainability of water management, represents a conservator par excellence.
This article appeared in the 2007/8 edition of Conservation and the Environment in Namibia.