The members of Green Hippo Innovations have been involved in various Water Research Commission projects. Some of these include:


Technical Reports


Energy Generation Using Low Head Hydropower Technologies
WRC Report No. 2219/1/16
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In the execution of this study attention was firstly given to identify the available low head hydropower technologies, followed by the identification of sites where the technologies can be implemented. A detailed description of the analyses of a potential WWTW site is provided. A pilot plant was constructed showcasing the application potential at low head installations.

Drainage Manual 6th edition, (SANRAL)

The South African National Roads Agency SOC Ltd (SANRAL) through an extensive process revised and updated the Road Drainage Manual (first published in 1981) which is now known as the Drainage Manual.  In realising the goals of producing a manual of high standard the co-operation between authors and reviewers to this and previous editions of the manual has been critical. In the manual it is endeavoured to take differing views into account which at times has proven to be a challenge. The manual is a summary of both historical and modern thought pertaining to drainage. This edition of the manual still covers all the previous background theory but has been extended to include additional flood calculation methods, the analyses and design of stormwater systems, the hydraulic assessment of existing culverts and the modelling of free surface flows and flood line calculations. With the further expansion of the manual it was deemed necessary to separate the manual into two distinct documents; the first being the Drainage Manual and the second being the Drainage Manual Application Guide.

Conduit Hydropower Pilot Plants

WRC Report No. TT 596/14

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Conduit Hydropower Development Guide.

WRC Report No TT597/14

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This research project indicated that it is feasible and technically possible to generateenergy from distributions systems. The hydropower development guidelines assist inidentifying locations, selecting the turbine and determining the feasibility thereof. Toassist in the feasibility calculations, showing that it is a viable investment cost functionshave been developed. The practical aspects are demonstrated with the threeconstructed, operational pilot plants installations.

Quantifying the influence of air on the capacity of large diameter water pipelines and developing provisional guidelines for effective de-aeration.
Volume 1+2
WRC report no. 1177/1/04 and    1177/2/04

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The influence of air on the capacity of pipelines has long been a cause for concern. Thequantification thereof was. however, unknown and required investigation. The investigation ofair in pipelines required a review of available literature, experimental work, fieldinvestigations and the development of provisional guidelines for optimal design to limit thenegative effects of air.The aims of this study were to:• Provide a literature review with regard to aspects related to air in water pipelines• Conduct experimental and field work to establish to influence of air in pipelines and• Compile a user guide for the design of effective de-aerated pipelines.

Application and conceptual development of genetic algorithms for optimization in the water industry
WRC Report No 1388/1/05
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This study evaluated the application of genetic algorithms in the optimisation of differentcomponents of water supply projects and conceptually developed the procedures for theimplementation thereof.

Based on the available literature study, as well as the feedback from water supply authorities.

the need for the application of GA’s as an optimisation technique in the water industry was

defined. The potential applications of GA’s in the water industry in South Africa are:

• Hydrology and water resources assessment.

• Network optimisation.• Optimisation of rehabilitation, extension and upgrading of distribution networksduring the planning and design phase.

• Operation and maintenance schedulingThis study objective was to provide the conceptual development of procedures toimplement GA’s as an optimisation technique for water resources assessment and networkoptimisation.

Factors influencing the friction loss in pipelines and the relationship between water quality, operating conditions and performance of liner systems.

WRC Report No 1269/01/06

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The aims of the study were:• The quantification of the factors influencing the friction loss in pipelines.• Establish the relationship between water quality, operating conditions and the hydraulicperformance of different liner systems and pipe materials.• Development of selection criteria for liner systems and pipe material.• Quantify the economic influence of increasing friction losses in a pipe system.• Development of a computer model to evaluate whether to replace, refurbish or extend existinginfrastructure components.• Establish the effectiveness of different pipe rehabilitation options on the friction loss characteristicsand liner integrity.

Life Cycle Costing Analyses for Pipeline Design and Supporting Software.
WRC Report No TT278/06
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The objectives of life cycle costing are: to enable investment options to be more effectivelyevaluated, to consider the impact of all costs rather than only the initial capital costs, toperform a sensitivity analysis and to assist the effective management of the completed project.This report is a simple guide to Life Cycle Costing Analysis, limited to the design/analyses ofbulk pipelines and emanated from research funded by the Water Research Commission(WRC) entitled “Review of factors that influence the energy loss in pipelines and proceduresto evaluate the hydraulic performance for different internal conditions”. During this study existing software was adapted that could assist designers in evaluating apipeline system over its full life cycle.

Waterborne Sanitation Design Guide.
WRC Report No TT481/11
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This report summarizes the available knowledge, information and advancements of allwaterborne sanitation systems used in South Africa. The objective of the report is toprovide a concise guide for the analysis and design of waterborne sanitation systems.In order to streamline the planning and design process in South Africa a three-tierphilosophy is proposed for sewage collection system planning and design.

Waterborne Sanitation Operation and Maintenance Guide.

WRC Report No TT482/11
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The aim of this guide is to highlight the procedures, practices and policies

in the operation and maintenance of waterborne sanitation systems.

Determination of the change in Hydraulic Capacity in Pipelines.
WRC Report No 1820/1/12
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This study aimed to

obtain as much as possible operational field data of a number of pipelines in order to:

• Determine the current roughness and derive the roughness variation and roughness decay;

• Compare the calculated roughness obtained from the field tests with the available literature;

• Compile a database to be used as a guide in selecting the appropriate expected future

roughness required in the design and optimisation of the water system components.

In the design of new pipelines or the refurbishment, upgrade or replacement of existing components

of the water supply system the cost of energy as well as the influence of biofilm growth in the pipeline

should also be reviewed. These aspects were also included in this research project.

Scoping study: Energy generation using low head technologies.
WRC Report no. KV323/13.
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The study illustrated that there is an untapped source of hydropower which should be

harnessed. It also reflected that the hidden or unused potential in run-of-river generation;

impoundments and irrigation schemes should be seen as priorities.

Status Review and Requirements of Overhauling Flood Determination Methods in South Africa.
WRC Report no. TT563/13.
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The intention of this project is to reflect the current state of flood determination methods used in

South Africa, reflect the shortcomings in the existing methods. This will then provide the basis to

identify the specific research areas and their priorities.

Two chapters in the book: The Role of Micro-Hydel for Developing Countries.  Centre for Science & Technology of the Non-Aligned and Other Developing Countries (NAM S&T Centre).

A Decision Support System for Energy Generation from Water Supply and Distribution Systems in South Africa

– Tapping into Hydropower Potential in Urban Water Distribution System – Developments in South Africa

The potential application
of Genetic Algorithms in
the water industry

WRC Report no. 1144/01/01

The past decade marks the development of computational capacity that far exceeds the capacity of the “instructor” to define options to be evaluated when optimisation has to be achieved.
The Government’s objective to provide “water for all” made it essential that the limited capital has to be employed to provide the maximum benefit. The optimal decision in terms of expansion, addition or rehabilitation of water supply systems has to review the conflicting demands and select a cost effective and efficient solution.
Within the context of water supply, there are numerous variables that can
influence the selection and hence the final cost of system improvements.
These variables include:
•The high variance in rainfall and runoff,
•the availability of alternative water supply,
•the demand pattern variability,
•the operational ability of the system,
•the maintenance requirements,
•the running cost-especially power cost and
•the affordability and willingness to pay for services.
The determination of the optimal selection of system components requires techniques that can be employedto assist the decision-maker in finding the appropriate solution within the environment of all the possible solutions
(Solution space).
The aim of this study was to evaluate the application of genetic algorithms in the optimisation of different components of water supply projects, viz:
•pump selection and scheduling
•optimal pipeline diameter selection
•valves and surge alleviating devices selection
•management of water supply projects
•alterations and extensions required in the upgrading
of the capacity of water supply infrastructure.

Grouted lining systems for
the renovation of old steel
pipelines and the design of
new pipelines

In South Africa steel pipes have been installed as late back as 1930.
Steel pipes amongst other need to be protected against corrosion. This is normally achieved by the provision of an internal lining and external coating. Some of the liner systems that have been used in the past have to be replaced and in the case of Rand Water the largest water utility, consideration is given to install grouted viscous-elastic liners in a number of their pipelines to extend their useful life. Practical challenges exist to install liners at joints, bends, pipe transitions, fittings, branches and at valves. In selecting a liner, one of the major aspects to consider is whether the pipeline still has sufficient structural capacity for the intended use. The structural contribution of the different layers in the composite pipe influences the buckling characteristics of the pipeline. Thus the objective of this study was to investigate alternative lining systems applicable for South African conditions.
The experimental work involved the following:
• Establish the ease of installation for liners which
could be used for steel pipelines;
• Test the installation of joints;
• Establish how the liner performs under high
internal pressure; and
• Determine if the liner could be installed along bends.
Through the experiments the study has demonstrated that HDPE liners do have potential in the rehabilitation of steel pipelines, since they also provide some structural strength and possible ease of installation, as well as overcome some of the problems associated with current lining practices. The study has shown that more work needs to be done on the use of the materials on pipe bends and other fittings.

Influence of Catchment
Development on Peak
Urban Runoff

The research reviewed catchment response due to urban development on the basis of comparative assessment. This required the identification of similar rainfall in the catchment during different development stages for which gauged flow rates were recorded. The hypothesis which was reviewed here relates to the statement that urban development which creates more impervious areas on the one hand also generated longer times of concentration due to the changes in the length of the flow path as well as more temporal storage capacity which could result in a higher groundwater recharge.
The hypothesis that the influence of urban catchment development will decrease the peak runoff has neither been proved nor disproved.

Journal Publications

Optimising Water Distribution Systems using a weighted penalty in a Genetic Algorithm. Water SA. Vol 34, No 5 pp 537-548.

Genetic algorithms (GA’s) have become the preferred water system design optimisation technique and the main reason for using GA’s is their ability to deal with nonlinear complex optimisation problems. This paper presents a new approach in determining a penalty value depending on the degree of failure, of the set pressure criteria, and the importance of the link supplying a specific node. Further modifications are also made in the cross-over and mutation procedures to ensure an increase in algorithm convergence. EPANET, a widely used water distribution network simulation model, is used in conjunction with the proposed newly developed GA for the optimisation of water distribution systems. The developed GA procedure has been incorporated in a software package called GANEO, which can be used to design new networks, analyse existing networks and prioritise improvements on existing networks. The developed GA has been tested on several international benchmark problems and has proved to be very efficient and robust. The EPANET hydraulic modelling software as well as the developed GANEO software,which performs the optimisation of the water distribution network, is freeware. The software provides a tool for consulting engineers to optimise the design or rehabilitation of a water distribution network.

Destratification induced by bubble plumes as a means to reduce evaporation from open impoundments. Water SA Vol 35, No 2 (Special WISA 2008 edition). pp 158 – 167.

The use of thermal mixing by means of compressed air appears to have important potential for evaporation suppression on deep reservoirs. The methodology proposed in this paper to help reduce evaporation losses from open-water impoundments, which indirectly addresses problems of water shortage and the associated economic impacts, involves the destratification of the water body using a bubble plume operated with minimal energy input to reduce surface water temperatures, with, a subsequent reduction in evaporation. The literature, although limited, indicates that this proposed method has merit and requires further research to identify specific reservoirs (size, depth, usage) that could benefit from such a destratification system. Evaporation suppression of as high as 30 % was achieved in some case studies.

Modelling the feasibility of retrofitting hydropower to existing South African dams. Water SA Vol 37 No. 5, WRC 40-Year Celebration Special Edition 2011. pp 679 – 692.

An investigation was carried out with the primary objective of ascertaining whether it is possible to develop a model for determining the feasibility of retrofitting hydropower to existing dams in South Africa. The need for such a model is primarily due to the growing importance of small-scale hydropower projects resulting from the global shift towards renewable energy and the South African energy crisis, the increased price of energy and the introduction of feed-in tariffs for renewables. The model is intended for engineers, typically working on behalf of a client who would like a simple first order assessment of feasibility. It therefore takes all technical, environmental, social and financial considerations into account in order to provide a recommendation on whether or not a project would be feasible.

Achieving the primary objective required an in-depth study of the theory and literature related to the current electricity situation in South Africa as well as all the different components and considerations of hydropower projects. This theoretical knowledge could then be utilised to develop a computer model which combines the most important considerations into a cohesive whole in order to make a recommendation on feasibility. The accuracy and applicability of the model could then be ascertained through testing, using actual case studies in South Africa. Three test cases were utilised which yielded positive results.

A number of difficulties were encountered. These related mainly to the development of an accurate means for pricing the different components primarily due to a lack of response from suppliers. Such issues were solved through the use of theoretical formulas and studies which provided good results. Ultimately, a model was developed which includes financial, environmental and social considerations and provides values that are accurate enough as an initial tool in determining whether or not to continue with a retrofitted hydropower project.

The discontinuity required at an air valve or vent or for effective pipeline de-aeration. South African Journal of Civil Engineers. Vol 54, No 2. pp 94-100.

The location and sizing of air valves to ensure effective de-aeration of pipelines and to provide vacuum break capability was researched. Based on these findings, software was developed to evaluate gravity and pumping systems. A sound understanding of the factors affecting the hydraulic transportation of air in a pipeline is paramount for locating air valves. When air is hydraulically transported to the position of release from the pipeline, it is necessary that the free air should be intercepted by a discontinuity and expelled via an air valve or vent arrangement. Research information on the layout and dimensioning of the discontinuity to ensure the interception of air in pipelines is lacking. This paper discusses experimental and numerical model assessments undertaken to compile provisional guidelines for determining the dimensions of the required discontinuity.

Conduit-hydropower potential in the City of Tshwane water distribution system. South African Journal of Civil Engineers. Vol 58. October 2014.

In water distribution networks, water is often fed under gravity from a higher reservoir to another reservoir at a lower level. The residual pressure head at the receiving reservoir is then dissipated through control valves (mechanically or hydraulically actuated), sometimes augmented by orifice plates where there is a propensity for cavitation. There are possibilities to add turbines in parallel and generate hydroelectricity at these locations using the flow and head available.

The benefit of this hydropower generating application is that minimal civil works need to be done, as the control valves are normally inside a control room/valve chamber. No negative environmental or social effects require mitigation, and the anticipated lead times should be short.

From a topographical perspective the City of Tshwane has a lower elevation than the bulk service reservoirs of Rand Water, which is the main water supply.

The top ten hydropower potential sites in the City of Tshwane water distribution network have a total energy generating capacity of approximately 10 000 MWh/a. A number of potential conduit-hydropower sites have shown promise of short payback periods. The identifying and development of these sites in Tshwane to convert water pressure to electricity is ongoing and exploited further.

Various challenges currently exist with reservoir communication in isolated areas due to vandalism and theft of necessary infrastructure, including electricity cables and solar panels. Because conduit-hydropower systems can be housed completely inside chambers, vandalism and theft can be mitigated. Therefore, one of the major benefits of hydropower turbines at these sites is that the hydroelectric potential could be exploited to power telemetry, pressure management, flow control and monitoring/security systems.

Alternatively or additionally, other local demand and/or (depending upon the quantum of energy available) off-site energy demand clusters, or even a municipal or national grid, could also be serviced by these power stations. The capacity of hydroelectric installations can vary to suit the application for the amount of power needed or to be generated. Short payback periods, especially when using pumps as turbines, also make conduit-hydropower systems attractive.

A Review of low head hydropower technologies and applications in a South African context. Renewable and Sustainable Energy Reviews. Elsevier. pp 1254-1268.

This paper provides a review of available low head hydropower technologies, followed by the identification of sites where the technologies can be implemented, applied specifically to a South African context. The potential sites where low head hydropower can be installed in

South Africa are grouped as follows: dams and barrages (retrofitting); rivers; irrigation systems (canals and conduits); and urban areas (industrial and urban discharge, storm water systems and water distribution systems).

A Feasibility and Implementation Model of Small-scale Hydropower Development for Rural Electrification in South Africa – Case study: Kwa Madiba SSHP Plant. Water SA Vol. 42 No. 4 pp 528 – 541.

Large numbers of households and communities will not be connected to the national electricity grid for the foreseeable future due to high cost of transmission and distribution systems to remote communities and the relatively low electricity demand within rural communities. Small-scale hydropower used to play a very important role in the provision of energy to urban and rural areas of South Africa. The national electricity grid, however, expanded and offered cheap, coal-generated electricity and a large number of hydropower systems were decommissioned. In this study, a feasibility and implementation model was developed to assist in designing and financially evaluating small-scale hydropower (SSHP) plants. The implementation model describes steps to be followed in identifying a technically possible and economically feasible opportunity to develop a SSHP site for rural electrification. The development model was used in designing the Kwa Madiba SSHP plant. The Kwa Madiba SSHP plant was economically evaluated on net present value, internal rate of return, levelised cost of energy, financial payback period and cost/benefit ratio. The outcome of this study proved that it is technically possible to provide SSHP installations for rural electrification in South Africa that are more feasible than local or national electricity grid extensions or even alternative energy sources such as diesel generators. It was concluded that the levelised cost of SSHP projects indicates that the cost of SSHP for low energy generation is high compared to levelised cost of coal-fired power generation. However, the remoteness of SSHP for rural electrification increases the cost of infrastructure to connect remote rural communities to the national electricity grid. This provides a low cost/benefit ratio and renders technically implementable SSHP projects for rural electrification feasible on this basis.

Legislation governing the implementation of small-scale hydropower projects for rural electrification in South Africa. Journal of Energy in Southern Africa. 28(2): pp 14–28.

The Department of Energy’s ‘new household electrification strategy’ allows for any appropriate and affordable technology option to be applied towards achieving South Africa’s non-grid electrification target of 300 000 households over the period 2014 to 2025. This paper describes the main legislative and regulatory framework governing the implementation of small-scale hydropower (SHP) projects in South Africa with the aim of attaining the objectives of the non-grid electrification component of the ‘new household electrification strategy’, and indicates that it is possible to implement such projects within South Africa’s complex institutional architecture. The inclusion of run-of-river type small-scale hydropower projects for rural electrification in the 2016 updated General Authorisation eased the process of attaining regulatory compliance in terms the National Water Act. This implies that these types of SHP projects would only need to follow a registration process to obtain the required water use authorisation, and not a full water use licence application process.

Have acted as referee for the following journal publications:
  • South African Institution of Civil Engineering

  • WaterSA

  • Journal of Water Supply: Research and Technology – AQUA

  • The Annals of the Brazilian Academy of Sciences

  • WISA