Research and Development Projects
New National Research and Method Development Projects
Guide to Eutrophication Assessments
DHEC contributed to the preparation of "A Guide to Catchment-Scale Eutrophication Assessments for Rivers, Reservoirs and Lacustrine Wetlands", now available as WRC Technology Transfer Report TT352/08.
Diatoms in Biomonitoring (Phase III)
This pivotal project, undertaken in association with North West University (Potchefstroom Campus) is probably the most exciting development in river and wetland biomonitoring in South Africa since the development of SASS! Phases I and II of this work, phases that evaluated the potential and need for this approach and developed a comprehensive toolbox of assessment tools, have been completed and are available as various reports and DVD-based products. Phase III will bring the use of diatoms into the formal biomonitoring arena, a process whereby the use of diatoms will join the already-developed vegetation, invertebrate and fish-based assessment protocols of the Ecostatus approach.
In addition to Phase III of the river and stream orientated work has been the development of a Diatom Index for use in the assessment of wetland health.
This study is an extension of two earlier phases of the development of a diatom-based biomonitoring toolkit. The National Water Act (NWA) ensures the protection of water resources, and therefore methods are needed to identify and categorize the health of aquatic systems. It is envisaged that the results from this study will be used in State of River reporting (in fact already implemented for some catchments) and will form part of the River Health Programme (NAEHMP). The Diatom Assessment Protocol (DAP) as a biomonitoring tool can be used to test the water quality of various waterways, including urban waterways. The Phase 3 study will deal with the formulation and calibration of a Diatom Index relevant to South African conditions. Through testing of diatom species over a time period, the species possessing of the greatest ecological importance will be used in the calculations. This study will determine those important diatom species to develop an SA-relevant index.
The Role of Foodweb Manipulation for the Restoration and Management of Enriched South African Dams
Recent work by DHEC and its associates mirrors overseas studies that illustrate the potential for impoundment restoration possible via restructuring of imbalance fishery assemblages. Our joint investigations with Ecodynamics, undertaken at Hartbeespoort Dam, have demonstrated options for sustainable, commercially-viable rehabilitation. Based on the findings of the Hartbeespoort Dam study this work will now be extended to a suite of 9 dams located in the Gauteng and North-West Provinces.
During July 2008 this project hosted its overseas partners from Denmark and Australia at a workshop held at the Roodevallei Country Lodge (Roodeplaat Dam). This workshop highlighted international experience with the application of this approach.
This project addresses the challenge of eutrophication through the application of food-web manipulation as a cost-effective management option for South Africa's most limiting natural resource, fresh water. Many South African waters are in an advanced state of eutrophication, viz. a plagio-climactic state dominated by a few taxa of coarse phytoplankton and fish. Such systems are resilient to remediation and require shock treatments such as the rapid, bulk removal of problematical fish, to allow the system to reset. In South Africa, eradication of common carp was seen as the first step in the rehabilitation of most dams experiencing eutrophication problems. This alien fish preys on zooplankton, feeds in open waters amongst macrophytes and contributes to sediment disturbance and water column turbidity. The project will develop a scientific understanding regarding the impoundments that largely supply all water user sectors (domestic, industry and agriculture).
The aims of this study are:
- Determine the fish assemblages at a suite of impacted and control dams located in the same eco-region, coupled with the identification of trophic state and eutrophication impact assessment.
- Determine harvesting requirements to reset the fishery to a desired assemblage.
- Determine harvesting requirements to sustain the desired assemblage.
- Collect data on specific abiotic and biotic components (phytoplankton and zooplankton assemblage).
- Compare and contrast commonalities of ecosystem response and degree of system specificity.
- Assess, in broad terms, economic and financial implications of the recommended approach.
- Identify constraints to the proposed rehabilitation methodology.
- Evaluate the findings in terms of the potential of this approach as a method for impoundment rehabilitation, as well as for commercial opportunities.
Other new projects
Toxic Algae in South Africa: Phase II Management Strategy
DHEC has been appointed as advisory and planning consultant to undertake the second phase of this work. In addition to addressing specific issues such as the risk associated with the possible occurrence of BMAA (beta methyl amino alanine) in South Africa, Phase II of this project will focus on the establishment of a South African Research Network for Algal Toxins (SARNAT) and the roll-out of industry (water utilities and irrigation boards) information and support networking. This will also parallel and incorporate South African input to the envisaged Phase II of the international, UNESCO-IHP funded CYANONET project.
February 2007 saw the hosting in Somerset West of a Global Water Research Coalition's (GWRC) workshop of the algal toxin working group. A key outcome of this workshop has been the preparation of an internationally-relevant manual on cyanobacterial assessment and management, a product that will be completed during 2009.
Pan-african diatom (Surirella sp.) project
DHEC was awarded the South African component of an international project, funded by the Mellon Foundation, to compile a photomicrographic record of African specimens of the diatom genus Surirella (Surirellaceae). This project was led by the National Botanic Garden of Belgium and South Africa (DHEC together with NWU) and the Botanical Museum of Berlin.
DHEC initiated & managed projects
Nutrient (phosphorus) loading limits (TMAPLs) for South African Dams
Modelling of the nutrient (phosphorus) loading and responses of a suite of 30 South African dams was completed during April 2007. This project identified the nutrient loading thresholds at which these dams become impaired, or are at risk of becoming so, by noxious algae. In so doing the work will set Target Mean Annual Phosphorus Loads (TMAPLs) as provisional guidelines for setting rehabilitation (load reduction) or protection (threshold loads) phosphorus loading limits. This project builds on the NEAP (Nutrient Enrichment Assessment Protocol) previously developed for the Water Research Commission.
South Africa is almost totally-reliant on storage of water in dams for water supply. In many cases, a large proportion of the flows to these dams is comprised of polluted stormwater runoff, agricultural return flows and wastewater effluents from urban developments. These return flows are characterized, in the main, by elevated concentrations of phosphorus. Ideally, the management (reduction/prevention) of eutrophication focuses on phosphorus attenuation. However, in South Africa, phosphorus elimination from wastewater and other effluents is not targeted as a priority. With eutrophication as the cause, the most common symptom is the increasing development of cyanobacterial aggregations, with the associated risk of cyanotoxin production. Cyanotoxins are notoriously difficult and costly to remove from raw potable waters.
This project categorized a suite of SA dams in terms of:
- Their current trophic status.
- The current matrix (mix) of phosphorus sources contributing to the total annual loading of this element into each dam.
- Setting maximum acceptable loading limits for each dam.
- Identifying, from the landuse profiles, where effective nutrient attenuation practices should be focused.
Report is available from the WRC or can be downloaded here.
Development of a low-cost technology for microhabitat temperature monitoring in South African rivers
One of biggest limitations to environmental flow planning is the lack of continuously-recorded temperature data. This projects aims to provide an inexpensive option to address this need.
This project, undertaken in association with UKZN, has been completed and has been highly successful in achieving the goals of developing a low-cost, low-maintenance temperature logging system, with associated hardware and software. An example of the raw data output from the logging devices is shown below. Initial trials are nearing completion and the results will be published shortly. It is envisaged that this pilot-scale testing will be followed by a second phase during which method refinement and scale-up for wider national use will be undertaken.
This project has been expanded into a second phase that has seen the Version 1 units substantially upgraded. Parallel work is integrating conductivity measurement and logging.
Development of a diatom-based assessment protocol for South African rivers and streams
Phase II of this project has been completed and a suite of tools are now available. Phase III is underway and due for completion during early 2010.
Options for Biomanipulation in South African Dams
This two-year project entails a detailed examination of the aquatic foodweb in Rietvlei Dam, Pretoria. The project will be completed in the third quarter of 2011.
Strategic Research and Management Plan for Toxic Algae in South Africa
WRC Report TT277/06.
Nutrient Enrichment Assessment Protocol (NEAP)
A web-based interactive tool for preliminary assessment of nutrient loading and management options.
DHEC participant projects
Development of Best Practice Guidelines and Implementation Strategies for the Management of Eutrophication in South Africa
A Department of Water Affairs Project led by Shands Consulting (Cape Town).
Development of a model to assess the costs associated with eutrophication
A Water Research Commission Project led by Ground Truth Consulting (Pietermaritzburg).
This work forms a sub-component of a larger, multi-disciplinary study. DHEC is tasked with identifying an appropriate First Order model that describes the nutrient (phosphorus) loading behaviour of the dams on the Vaal River (Grootdraai, Vaal, Bloemhof and the Barrage). This, together with other tasks allied to eutrophication, will be completed during 2007/8.
Development of a diatom-based condition index for South African wetlands
DHEC, in association with North-West University, has been awarded a consultancy to develop a provisional diatom-based index for wetland environments. This project is due for completion during 2009.