HARTBEESPOORT DAM REMEDIATION Future challenges and prospects INCREASING CHALLENGES of the Hartbeespoort Dam Integrated restore healthy ecosystems through biodi- Th e positive changes (more and longer Biological Remediation Programme, are a versity. Th is principle to conserve, protect periods of clear water experienced since clear indication of the powerful potential and manage towards optimum biodiversity 2009, absence of bad odour, etc) recorded available within an integrated approach is not only a requirement in the National within 18 months after the implementation towards unlocking nature’s ability to Environmental Management Act (Act 107 of 1998), but is echoed in the National Water Act (Act 73 of 1998) through the Flow increases at Kalkheuwel requirements of the Reserve to manage 700 towards aquatic ecosystem diversity. Th e world has experienced tremendous 600 population growth over the past several 500 decades, a situation that is no diff erent in /a) 3 South Africa. Water is essential for humans 400 in many ways, including water supply and 300 storage, land value enhancements, recrea- Flow (million m Flow tion, aesthetics and even transportation 200 (larger river systems). Communities there- fore normally settle and grow near areas 100 where there is a relatively sustainable water 0 resource. However, the increasing popula- 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 tion growth is threatening the quality and Date quantity of both surface and ground water, Figure 1: Flow increases in the Crocodile River (1923–2011) especially in the highly developed urban Figure 2: Delineation of the Hartbeespoort Dam catchment Civil Engineering August 2012 53 areas, posing signifi cant challenges when it in signifi cant quantities of additional water urban and bushveld mining complex comes to sustainable water resource man- being piped into the region to satisfy water (platinum, chrome and base minerals) agement, which is only possible if done in an demand. Th e present supply from Rand developments north of the Hartbeespoort integrated manner. Water to these areas amounts to about Dam, and will in the immediate future It should be noted that the 2 900 Mℓ/d, of which about 50% is within become even more important for supply up Gauteng metropolitan area (covering the Hartbeespoort Dam catchment. Th e to Lephalale (Ellisras Municipality) for the Johannesburg, Ekurhuleni, Mogale and signifi cant increases in return fl ows from extension of the Medupi Power Station. Tshwane) is one of the few large metro- these areas, as measured at the infl ow to To integrate and harmonise the politan areas in the world not based near the Hartbeespoort Dam, can be observed various environmental, biological, engi- an ocean port or a major river, and which from Figure 1. Th e total volume of return neering and socioeconomic aspects to is therefore entirely, or to a great extent, fl ows discharged upstream from the dam ensure sustainable solutions, requires dependent on imported water. ranges from 650 to >720 Mℓ/day, with an the involvement of a number of scientifi c Th e Gauteng municipalities have increasing trend as depicted in Figure 1. and engineering disciplines. With the experienced marked growth and develop- Th ese return fl ows have become an world population that has more than tri- ment over the last few decades, resulting important source of water supply to the pled over the last century, the per capita green footprint has increased between 9 and 50 times (third-world and fi rst). Restoring the dam to its natural state Environmental impacts are still skyrock- eting, with fewer resources available to an ever growing modern civilisation. Th e ability of eco-engineering to utilise and integrate all disciplines to package the best environmental option, might be seen as the most appropriate way to go ahead. Society needs to start taking respon- sibility for the current level of environ- mental degradation and water pollution. The Waste Discharge Charge System (WDCS) was established to promote waste reduction and water conservation under the National Water Act of 1998 (Act 36 of 1998). In terms of section 56 of the NWA, the WDCS endeavours to introduce financial and economical in- struments aimed at sustainable develop- ment and utilisation of water resources, Floating wetlands form part of the HBPD remediation programme 54 August 2012 Civil Engineering The state of the Hartbeespoort Dam has improved markedly since the start of the remediation programme internalisation of environmental costs, 1. On-going operation and maintenance undesired material reaching the dam, but and recovery of costs from the water (+R25 million/annum) preventing them from reaching the dam in user/polluter. The WDCS forms part of 2. Fast-tracking (present 2012/2013 al- the fi rst instance. Th is will entail a complete the pricing strategy where charges (in- location of +R50 million/annum) roll-out of the programme as specifi ed centives and mitigation charges) could 3. Full-scale implementation of the within the business plan, including the be levied from water users, based on the Hartbeespoort Dam Remediation long-term pre-impoundment and litter trap polluter-pays principle. Programme, and extension of acquired projects. In addition it will include providing Th erefore, the WDCS is primarily a knowledge and experience to other assistance to the Department of Water framework for charging for the discharge dams and catchments (+R120 million/ Aff airs through the licensing of the various of waste into water resources. It aims to annum over three to fi ve years) water uses around the Hartbeespoort use economic instruments to encourage Ongoing operation will include the continu- Dam, and the implementation of the Waste polluters to internalise the social, eco- ation of tasks that will ensure the mainte- Discharge Charge System (WDCS). nomic and ecological costs of discharges. nance of the current positive state of the Th e ultimate objective is to reduce the dam – biomass management (removal and LAST WORD amount of waste that is discharged into treatment of algae, hyacinths, litter and Th ere is no quick, easy and cheap solution the country’s scarce water resources. debris, the establishment of fl oating to rectify a problem that has developed As part of the strategic development wetlands, and the remediation of the over more than 80 years. Th e restoration of the system, testing will be done by shoreline) and food web restructuring (fi sh of the Hartbeespoort Dam cannot be piloting the WDCS within the Crocodile removal) programmes. Th ese programmes considered a once-off action, but should (West) Marico Water Management Area. (which enhance the biodiversity and the rather be seen as a series of well-planned, It is foreseen that the WDCS will cover nutrient fi ltering capacity in the dam) will integrated measures within the dam basin for a budgetary shortfall of 50% to meet be the least of the operations required to and the Crocodile River catchment. Th ese the required funding for catchment man- ensure that the food web cycle within the measures, the intensity of which would vary agement. An estimated income in excess dam is managed in a manner that will pre- depending on the programme’s implemen- of R400 million could be generated within vent the excessive hypertrophic state that tation phase, should be strictly and persist- this sub-catchment, also providing funds the dam is prone to. ently carried out, now and in the future. for the HBPD remediation projects. Fast-tracking will include the tasks fo- Currently these activities are cused on the reduction of the dam’s internal focused on the dam basin, and on de- FUNDNG SCENARIOS nutrient load (incoming sediment removal velopment of an improved catchment Th e future of the programme is de- and management) as a prerequisite to management strategy, but future activi- pendent on seeding funds from National making a considerable positive impact on its ties will mostly deal with catchment Treasury, and on external funding to be ecosystem health and water quality. management and maintaining of at- recovered from waste discharge charges, Full-scale implementation will include the tained trophic levels in the dam. as discussed above. Th ree funding sce- continuation of all the identifi ed projects narios have been identifi ed, namely: in order to not only alleviate the eff ects of Petrus Venter Civil Engineering August 2012 55 .