Water Safety Plans for Utilities in Developing Countries - a Case Study from Kampala, Uganda
Total Page：16
File Type：pdf, Size：1020Kb
Water Safety Plans for Utilities in Developing Countries - A case study from Kampala, Uganda Sam Godfrey, Charles Niwagaba, Guy Howard, Sarah Tibatemwa 1 Acknowledgements The editor would like to thank the following for their valuable contribution to this publication: Frank Kizito, Geographical Information Section (GIS), ONDEO Services, Kampala, Uganda Christopher Kanyesigye, Quality Control Manager National Water and Sewerage (NWSC), Kampala, Uganda Alex Gisagara, Planning and Capital Development Manager, National Water and Sewerage (NWSC), Kampala, Uganda Godfrey Arwata, Analyst Microbiology National Water and Sewerage (NWSC), Kampala, Uganda Maimuna Nalubega, Public Health and Environmental Engineering Laboratory, Department of Civil Engineering, Makerere University, Kampala, Uganda Rukia Haruna, Public Health and Environmental Engineering Laboratory, Department of Civil Engineering, Makerere University, Kampala, Uganda Steve Pedley, Robens Centre for Public and Environmental Health, University of Surrey, UK Kali Johal, Robens Centre for Public and Environmental Health, University of Surrey, UK Roger Few, Faculty of the Built Environment, South Bank University, London, UK The photograph on the front cover shows a water supply main crossing a low lying hazardous area in Kampala, Uganda (Source: Sam Godfrey) 2 TABLE OF CONTENTS: WATER SAFETY PLANS FOR UTILITIES IN DEVELOPING COUNTRIES.1 - A CASE STUDY FROM KAMPALA, UGANDA..................................................1 Acknowledgements.................................................................................................2 Introduction: ..........................................................................................................4 Development of Water Safety Plan (WSP): ...........................................................5 Stages of Implementation.......................................................................................7 Stage 1: Forming WSP steering group:.................................................................7 Stage 2: System description:..................................................................................9 Concepts of Risk Maps.........................................................................................12 Hazards................................................................................................................13 Vulnerability ........................................................................................................13 Susceptibility........................................................................................................14 Stage 3 Development of assessment tools:...........................................................15 Stage 4: System Assessment:................................................................................17 Stage 5: Development of Risk Maps ....................................................................19 Hazard Assessment:.............................................................................................20 Vulnerability Assessment:....................................................................................23 Vulnerability Maps: .............................................................................................31 Susceptibility........................................................................................................34 Key Findings:.......................................................................................................36 Stage 6: Water Safety Plan ..................................................................................38 Stage 7: Verification exercise (water quality assessment and audit) ..................44 Results..................................................................................................................46 Recommendations:...............................................................................................49 Future Work.........................................................................................................52 Bibliography ........................................................................................................53 3 Introduction: The most effective way to achieve safety of drinking water is through the adoption of quality assurance schemes that ensure water supplies are designed, operated and maintained properly. The development of quality assurance schemes has been identified by WHO as the principal mechanism for ensuring water safety and refer to these as Water Safety Plans (Davison et al., 2002). A full discussion of the concepts of Water Safety Plans may be found in Davison et al. (2002) and in Howard et al. (2002). This case study documents the findings of a research project funded by Department for International Development (DFID) undertaken by the Water, Engineering and Development Centre (WEDC) in collaboration with the Uganda National Water and Sewerage Corporation (NWSC) and the Public Health and Environmental Engineering Department of Makerere University. This research project examines the methods and tools required to apply the WSP framework to water utility systems in developing countries. It documents the development of methodologies and tools for a Water Safety Plan developed for a large utility system in Kampala, Uganda. In addition, the case study presents a risk map of the system, which identifies hazardous and vulnerable areas. The structure of the case study follows the stages of field implementation of a Water Safety Plan and risk mapping. The case study begins with a brief description of the Kampala system and then goes onto describe the key requirements for the successful implementation of a WSP. These requirements include the establishment of a local led steering committee as well as reliable baseline data on both the treatment and distribution network’s performance. The case study then examines the tools and methods required to undertake a comprehensive system assessment. Findings from this assessment and from a comprehensive literature review are then combined to identify control points within the supply. Finally, the case study presents a Water Safety Plan for Kampala, with management actions and monitoring programmes for managing water-related risks. 4 Development of Water Safety Plan (WSP): A Water Safety Plan (WSP) is a management tool designed to optimise performance management of piped water systems. The development of a WSP follows a structured 12-point process as shown in figure 1 below. Figure 1. Steps in the development of a Water Safety Plan Water Safety Plan 1 Set Water Quality Objectives 2 System Assessment 3 HACCP Supporting Programmes 1. Assemble team Ensure control measures are managed through supporting programmes: eg 2. Describe water supply Commitment Training 3. Define intended use Document control 4. Construct system flow diagram Good design and operation Calibration of equipment 6.1 Identify Hazards 5. Validate flow diagram 6.2 Prioritise Hazards Community education 6.3 Identify existing control measures Community consultation 6. Conduct hazard analysis 7. Identify control points 7.1 Identify control measures for inclusion as control points 72. Identify control measures as part of supporting programmes 8. Define operational limits programmes 9. Establish monitoring 10. Establish corrective options 11. Establish record keeping 12. Establish validation and verification 5 For distribution systems, the above process can be summarised as being covered by 7 core areas of activity as shown in figure 2. Figure 2: Development of WSP Review of existing Forming WSP data / System steering group Description / Zoning System Assessment Establish Development of / Validation of Vulnerability / tools - Analytical Tools Hazard Matrix & training Map Development of Verfication and Risk Maps Refinement of WSP Examples outlined in this document are based on field work undertaken in Kampala, Uganda between January and November 2002. It is important to note that the WSP alone can not ensure the provision of safe drinking water. As well as the WSP, there are two fundamental additions, namely: - Prerequisites - Supporting Programmes Supporting programmes can be defined as the foundation activities required to ensure safe water (Davison, 2002). Examples include ensuring water treatment works operate at optimum design capacity for water quality control and hygienic working practices, as documented in maintenance Standard Operations Procedures (SOP’s). In Kampala, this of increasing importance due to the increased pollution of the source water in Lake Victoria and particular concerns regarding algal blooms. A supporting programme in this case would be to ensure that the clarification process in the treatment works is able to cope with increased algal loading. This would particularly address design constraints encountered in the mixing channels to ensure more 6 effective floc formation. An upgrade of these clarifiers would then guarantee adequate quality of treated water into the distribution network Prerequisites can be defined as absolutes required to ensure the successful implementation of the WSP. For example, the success of WSP is dependent on full cooperation and understanding from the senior management. To achieve this in Kampala, senior members from both NWSC and from the system operator, OSUL (Ondeo Services Uganda Ltd) participated in detailed discussions of the WSP and how the WSP could assist NWSC in managing the Kampala system more effectively. Stages of Implementation