The Mokolo River
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State-of-Rivers Report the Mokolo River a Catchment in the Limpopo Province August 2006 River Health Programme Acknowledgements ontext of this Report Contributors C MK Angliss The Mokolo River Catchment was prioritised for study during Dr GCO de Beer 2002 by Limpopo Environmental Affairs, due to growing V Egan concerns relating to reed encroachment, the spraying of PJ Fouche weeds with herbicides and water delivery for the agricultural PSO Fouche sector downstream of Mokolo Dam. Furthermore, flows were J Mandoma released from Mokolo Dam to meet agricultural demand PH McMillan without due recognition of the downstream environmental SSM Rodgers consequences. The lack of a formal Ecological Reserve to M Silberbauer address ecological flows was thought to be a serious omission in the ecological management of the lower Mokolo River. Field work team MK Angliss The ecology of the Mokolo Catchment had never been L du Preez addressed in a multi-disciplinary, holistic fashion; with only PJ Fouche limited historical data being available from fish surveys PSO Fouche between 1965 and 1984. J Heymans E Netshiungani A detailed survey of the catchment was therefore long SSM Rodgers overdue, not only in terms of requirements for the River Dr K Rowntree Health Programme (RHP), but also in terms of the provincial Dr R Wadeson and national objectives to produce an up to date State of L Wiggins Environment Report (SOE). Photographs MK Angliss Participating Organisations PJ Fouche PSO Fouche Department of Environmental Affairs and Tourism (DEAT) J Mandoma PH McMillan Department of Water Affairs and Forestry (RQS) SSM Rodgers Water Research Commission Reviewers Dr PJ Ashton Limpopo Environmental Affairs: Dr N Kleynhans (Department of Economic Development, Environment and W F Strydom Tourism - LEDET) S Jhupsee A Kühn Rhodes University B Madikizela S Mitchell Venda University of Science and Technology C Shine C Thirion Working for Wetlands C Todd CSIR Natural Resources and the Environment Editing and Graphic Design Suggested citation: PH McMillan River Health Programme (2006) State-of-Rivers Report The Mokolo River System Department of Environmental Affairs and Tourism Pretoria ISBN No. 978-0-620-38215-1 ontents C page 2 State-of-Rivers - Introduction 3 State-of-Rivers - Limpopo Province 4 River Health Programme Indices 6 Overview of Study Area 8 EcoRegions 10 Ecological Study Units 12 the Sand River Tributaries 14 the Sterkstroom Catchment 16 the Rietspruit Catchment 18 the Upper Mokolo Region 20 the Middle Mokolo Region 22 the Lower Mokolo Region 24 Working for Wetlands - Report on the Mokolo River 26 Fauna and Flora 26 Indicator Fish Species of the Mokolo Catchment 29 Riparian Vegetation 32 Potential Catchment Developments 33 Bibliography 34 Summary 36 Management Required 37 Summary Diagram Information Boxes 2 State of Environment Reporting 2 The River Health Programme 7 Mokolo Dam and the Downstream Environment 17 Reeds and Terrestrial Vegetation 17 Alien Vegetation 23 Sand Mining 25 Rock Gabions 27 Scientific and Common Names of Fish in the Mokolo Region 28 Alien Fish Species 29 Classification of Trees and Shrubs for the Mokolo Catchment 30 the Status of Hippopotamus in the Mokolo / Limpopo River Systems 31 Herpetofauna in the Mokolo Catchment Provincial Champions: NOTE: Mick Angliss Paul Fouché the Mokolo River Limpopo Dept. of Economic Dept. of Biological Sciences, is also known as the Development and Tourism University of Venda, Thohoyandou. (LEDET) Polokwane. Mogol River tel: (015) 295 9300 tel: (015) 962 8453 and the [email protected] [email protected] Mogolo River State-of-Rivers: Introduction State-of-River reports are a sub-category of State-of-Environment reporting, which was promoted at the United Nations Conference he River Health Programme on Environment and Development in 1992. T The River Health Programme is a national State-of-River reports provide information at monitoring initiative measuring and reporting on a non-technical level to a wide audience: the ecological state of South African river systems. (politicians, managers, local authorities, It measures the biological and habitat integrity farmers, scholars and the general public, of rivers, which enables assessments of the etc.). The reports can help decision-makers ecological state of the river systems in a consistant and others see the complete catchment manner. Information from the River Health overview; guide scholars with projects; and Programme identifies areas where unacceptable provide information that may not have been ecological deterioration is taking place. The RHP easily available. Everyone can benefit from can also show the effectiveness of existing river these reports, as they are easy to understand, management policies, strategies and actions. provide a range of environmental information, and are freely available. Further information can be found on the River Health Programme website: Making communities aware of their www.csir.co.za/rhp environment is a very important step towards helping them to conserve their environment. State of Environment reporting As a signatory to the Convention on Biological Diversity, South Africa is obliged to develop environmental indicators and to produce periodic State of Environment (SoE) reports. The responsibility for producing detailed environmental reports, has been delegated to the provincial environmental authorities. It is the responsibility of the National Department of Environmental Affairs and Tourism to integrate provincial assessments and to provide the international community with a summarised national assessment. The first national assessment was completed in 1999. State of Environment reports are intended to support sustainable development and decision making through the provision of credible environmental information. State of Environment reporting plays an important role in assessing and interpreting data, and making it readily available and meaningful to both decision-makers and the public, thereby creating an important communication channel between scientists and the authorities. In Limpopo Province, Limpopo Environmental Affairs published an introductory, phase 1 State of Environment report in 2004, while a more detailed, phase 2 report is due for publication in 2006. In terms of aquatic biodiversity, those monitoring indices developed within the River Health Programme, together with a structured monitoring plan, provide important information for the provincial State of Environment report. page 2 State-of-Rivers: Limpopo Province Published State-of-River reports in the Limpopo Province Years Technical SoR Catchment Indicies Used * Training ** Surveyed Report Reports Phalala 1997 DWAF FAII, SASS4 Recieved No No 2005 FRAI, SASS5, RVI, Given In Prep. No GI, IHI, Ecostatus, EIS Sand 1997 FAII, SASS4, RVI Received No Yes 2001 FAII, SASS5 Given Yes No Olifants and 1998 DWAF FAII, SASS4, RVI Received No Yes Tributaries 1999 DWAF FAII, SASS4, RVI Given No Yes 2003 FAII, SASS5 Given Yes No Luvuvhu 1999 FAII, SASS4, RVI, GI Given Yes Yes 2003 FAII, SASS5 Given Yes No Letaba 2000 FAII, SASS5, RVI, Given Yes Yes GI, IHI 2003 FAII, SASS5 Given Yes No Mokolo 2002 and 2006 FAII, SASS5, RVI, GI, Given Yes This Report IHI, Ecostatus, EIS Crocodile and 2004 - 2005 FRAI, SASS5, RVI, Received and Yes Yes Marico GI, IHI, Ecostatus, Given EIS * See page 4 for a description of indicies used ** Training received by, or given by, LEDET The Dept. of Economic Development, Environment and Tourism (LEDET) surveyed the rivers in collaberation with: - Sand River, with the Kruger National Park (KNP), and Mpumalanga Province; - Olifants River, with DWAF, KNP, Gauteng and Mpumalanga Provinces; - Letaba and Luvuvhu Rivers, with the KNP; - Crocodile (West) and Marico Rivers, with DWAF, Gauteng and North-West Provinces. Limpopo Province Luvuvhu Phalala Letaba Mokolo Olifants Marico Sand Crocodile The map shows the location of catchments with existing State-of-River reports. The white areas are catchments where State-of-River reports still have to be produced. page 3 River Health Programme Indices RHP Indices Used in this Report: FAII: Fish are good indicators of long-term influences on general habitat Fish Assemblage Integrity conditions within a river reach. The FAII is an expression of the degree to Index which a fish population differs from its expected undisturbed condition. RVI: Healthy riparian zones help to maintain the form of the river channel Riparian Vegetation and act as filters for sediment, nutrients and light. Plant material from this Index zone is an important source of food for aquatic fauna. RVI is a measure of the degree of modification of the riparian zone from its natural state. SASS: Aquatic invertebrates require specific habitats and water quality South African Scoring conditions. They are good indicators of recent localised conditions in a System (macro- river. SASS is an index, based on invertebrate families found at a site. invertebrates) Other Indices Used: D-HI: Different types of habitat and their make-up help to determine the Desktop Habitat Integrity types of biota that are present in a river. This desktop version of the IHI extrapolates data, based on methodology in Kleynhans et al. 2005. GI: Geomorphological processes determine the size and shape of river Geomorphological Index channels, which in turn define the type of habitat. The GI reflects the channel condition and channel stability. EcoStatus: All the features and characteristics of the river and its riparian areas that influence its ability to support the natural