WATER SUPPLY SERVICES

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1 PRACTICE MANUAL FOR WATER SUPPLY SERVICES IN KENYA PART A WATER SUPPLY A 1

2 LIST OF CONTENTS PART A - WATER SUPPLY Page: A1 1. INTRODUCTION A Background A Purpose A Water Supply Administration A Legal framework A Institutional framework A Water Supply Service Boards A Water Supply Planning A Basic Planning A Basic Policy A Basic Objectives A Water Planning Coordination A Selection Criteria Principles A General A Parameters for selection A Instruction to users of the manual A Classifications A Urban Service centres A Urban Housing classes A Rural land potential A Livestock potential A23 2. WATER DEMAND A Design Period A Projection years A Design demand A Residential Demand A Population projections A Service type A Livestock Demand A Livestock population projections A Service level A Institutional demand A Schools A Health facilities A Commercial and Industrial demand A Small shops, workshops, Restaurants, Bars etc A28 A 2

3 2.5.2 Large enterprises, tourist hotels military camps etc A Other demands A Irrigation A Fire-fighting A Internal demand in the water A Water consumption rates A General A Rates A Consumption Patterns A Rural areas including rural market and local centers A Principle towns and urban centers A30 3. WATER QUALITY A General A Basic Requirements A Bacteriological Quality A General A Guideline values for distributed water and bottled water A Remedial action on Bacteriological deficiencies A Guideline values for raw water A Chemical Quality A Constituents of health significance A Desirable aesthetic quality A Permissible aesthetic quality A Substances and characteristics Affecting Building and Pipe materials. A General A Cement Products A Steel and Iron products A Water Samples A Sampling for selection of source and treatment A42 4 WATER SOURCES A General A General selection considerations A Specific selection consideration A Rivers and Streams A Safe yield for principle towns and urban centres with population A44 over 10, Safe yield for rural areas, urban centres with population under A44 10,000 and rural, market and local centers Flood flow A Flow analysis A Springs A Location and reliability A48 A 3

4 4.3.2 Yield A General method for spring tapping and protection A Boreholes and wells A General A Fully exploited aquifers A Only partly exploited aquifers A Manual water level observations A Yield records from existing boreholes A Borehole spacing A Criteria for successful rate of boreholes A Sub-surface dams A General A Withdrawal of stored water A Withdrawal of sub-surface flow A Sand dams construction and suitability A Artificial Recharge A General A Bank infiltration A Artificial aquifer A Rainwater harvesting A Rainfall Data A Run-off coefficients A Roof Catchments A Selection of Tank size A Harvesting of rainwater A Length of Dry spell in Kenya A Rock catchments A59 5. INTAKE STRUCTURES A River Intake A Location A Structures A Screens A Intake In Lakes and swampy areas A Location A Design details A Borehole Intakes A Setting of the Intakes A Design details A Spring Intakes A Protection A Storage chamber A Roof Catchments A General A Roof material A64 A 4

5 5.5.3 Roof guttering A Foul flush A Storage tank A Dug Wells A Diameter & depth A Lining A Protection A Drilled Wells A Hand-drilled wells A Mechanical wells drilling A Infiltration Galleries A General A Gallery in slowly permeable material A Gallery in permeable riverbed A Gallery in ephemeral or intermittent stream A Collection pipe A68 6. WATER TREATMENT A General A Required water quality and water samples A Principle towns and urban centres A Rural areas A General design considerations A Phasing of treatment works A Prolonged storage A General A Design details A Infiltration A General A Design details A Plain sedimentation A General A Design details A Roughing filtration A General A Up flow filters A Horizontal gravel filters A Coconut fibre filters A Rapid roughing sand filters A Aeration A Surface water A Ground water A Cascade aerator A Multiple tray aerator and Diffuser A Coagulation A74 A 5

6 6.7.1 Rapid mixing A Gravitation mixing A Mechanical mixing A Coagulants A Flocculation A Gravitational flocculation A Mechanical flocculation A Power input and detention period A Sedimentation A Inlet A Outlet A Horizontal flow settling tanks A Vertical flow settling tanks A Rapid sand filtration A Design details A Filter media A Supporting bed A Backwashing A Slow sand filtration A Limitations A Design details A Filter media A Disinfections A Application A Chemical disinfectant A Feeders A Contact period A Pot chlorination A Flow measurements A General A Thompson weir A Rectangular weir A Buildings A Workshop and laboratory A Office A Chemical store A Pipe Store A Staff Houses A Miscellaneous A Access roads A Safety measures and devices A Flush water A Marking A Fencing A Transport facilities A97 A 6

7 7. TRANSMISSION AND DISTRIBUTION LINES A General design aspects A System design A Method of supply A Pipeline design A Phasing A Spacing of primary and secondary pipelines A High and medium potential areas A Low potential rural areas A Urban areas A Pipes A Material selection - General A Material selection corrosion aspect A Design Dimensions of UPVC pipes A Friction losses A Cover and slope of pipes A Pumping mains A Pressure A Water Hammer A Corrosion Protection A General corrosion protection A Special protection A Open conduits A Application A Hydraulic design A Air release valves A General A Small - orifice valves A Large orifice valves A Alternative air releases A Isolating valves A Washouts A General A Location A Washout size A Washout valves A Fire-fighting A General A Pipes A Hydrants A Section valves A Location A Break pressure tanks A117 A 7

8 General A Size A Design details A Markers posts A Location A Type A Valve chambers A Dimension and Design A Anchor and thrust blocks A Location A Thrust forces on pipes A118 8 DISTRIBUTION POINTS A Individual connections (IC) A General A Meters A Communal water points and kiosks A Siting in rural areas A Siting in urban areas A General design details A Number of taps A Wells (point distribution) A General A Siting A Cattle troughs A General A Siting A Design A Fire hydrants A General A122 9 WATER STORAGE A General A Purpose A Rural areas A Balancing storage A Emergency storage A Urban areas A Balancing storage A Emergency storage A Raw water reservoirs A Raw water balancing A Tank design A Capacities A125 A 8

9 9.5.2 Design details A PUMPS AND POWERS SOURCES A Pump selection A Pumps commonly used A Power requirement A Suction head A General A Practical suction head A Net positive suction head (NRSH) A Pump particulars A Hand pumps A Centrifugal pumps A Submersible pumps A Hydraulic rams A Power sources A Diesel engines A Generators A Electrical motors A Wind power A Solar power A Pump and pipe installations in the pump house A Pump installation and pump house A Pipe installation, general details A Head losses in piping A Spare parts A Operation hours A General A Raw water pumping station A Borehole pumps A Stand-by units A Raw water and clear water pumps A Electricity supply A Borehole pumps A Wind powered pumps A System reliability A Phasing A Design period A Staging of the pump installation A Hand pumps Installations A Capacities of Hand pumps A Comfortable operation of Hand pumps A Cost consideration in selection of hand pumps A Protection of Health A Types of hand pumps in Kenya A151 A 9

10 10.11 Wind power Installations A Introduction A Size of wind mill A Technical Data A Maximum Pumping Head A Application of Wind pump A Wind potential in Kenya A Solar power Installations A Advantages A Available solar radiation & design A OPERATION AND MAINTENANCE A Operation A Objective A Institutional arrangement A Staffing A Records A Records of Permanent Construction A Records required for Operation and Maintenance A Updating records A Treatment works - Operational Procedures A Public Relations A Laboratories A A Maintenance A Purpose A Maintenance programs A Maintenance Systems A Types of maintenance A Preventive/Planned maintenance programme A Maintenance of Other Assets A Organisation for breakdown and Emergency A Workshop A Purchases A Receipt, Issue and Control A165 A Unaccounted For Water (UFW) A Definition A Components of UFW A MANAGEMENT MODELS A Legal framework A Registration A Registration Laws A168 A 10

11 The Companies Act Cap 486 A Co-operative Societies Act Cap 496 A Societies Act Cap 108 A The Non-governmental Organisations Co-ordination Act No. 19 of 1990 A Ministry of Culture and Social services A Comparable Advantages and Disadvantages of registration regimes A Companies Act Cap 486 A Co-operative Societies Act Cap 496 A The Non-governmental Organizations Co-ordination Act A172 No. 19 of Societies Act Cap 108 A Conclusion A INFORMATION TECHNOLOGY A Introduction A Information technology A Computer A Hardware A Software A The Internet A General A Functions A ,3 Using Internet A Data and Information Transfer and Retrieval A The Web A Benefits of Internet A Problems of Internet A Spreadsheet A Definitions A GIS Database A Introduction A Definitions A Digital Data for GIS A Feature definition in GIS A Feature Attributes A Feature Relationships A Sources of Data for GIS Database A Computer Aided Design (CAD) A Introduction A CAD Capabilities A Tools and Methods for CAD A CAD Application in Water Supply Services A Hydraulics Mathematical Models applications A Models and Modeling system A182 A 11

12 Application of Mathematical Models A Development of Mathematical Model A Candes (Canal design) A Objective A Data Inputs A Outputs A Profile A Objective A Inputs A Outputs A Flop (Flow Profiles) A Objective A Inputs A Epanet 2 A Objective A Modeling capabilities A Sewer (Civil Designer) A Objective A Sewer functions A CAD Advantages A CAD Disadvantages A DRAWINGS A Scales A General A Format A Construction, Standard and types drawings A Title block A Bar scheduling A Building and Civil engineering drawings bar scheduling A Water Supply drawings A Water supply general A Geotechnical drawings A Installation drawings A Pipeline drawings A Plan and profile drawings of pipelines A Flow chart for drawing procedure of piping diagrams A Building and structural drawings A General A Shuttering A Reinforcement A Installations A Standard drawings A Definitions A Available Standard drawings A195 A 12

13 14.8 Type drawings A Definitions A Available type drawings A COST ESTIMATES A General A Purpose A Methodology A Price charges A Construction costs A Pre-preliminary design stage A Preliminary design stage A Final design stage A Tender stage A Supervision stage A Maintenance costs A Annual maintenance costs A Operation costs A Manpower costs A Energy costs A Chemical costs A Miscellaneous costs A Land acquisition A Electricity lines A Design costs A Supervisor costs A Establishment costs A Depreciation costs A Capital costs A Foreign and local components A Pipelines A Mechanical and Electrical equipment A Revenue A Present day tariff A Selection criteria and presentation of costs A Present value analysis A Presentation of costs A Cost of establishing M & E System A General A STANDARDS A General A Preferred standards A New standards A205 A 13

14 Standards for materials used in existing plants A Standards relating to water quality A Standards valid in 1983 A Units A SI units A Formats A General A Preferred formats A Pipes A UPVC pipes A Designation of UPVC A Steel pipes seamless or welded A Locally manufactured steel pipes A Polyethylene Plastic (PE) Pipes for Water Supply (low and high density) A REPORT WRITING A General A Purpose A Report Standard A Report Contents A Preliminary design report (PDR) A Final design report (FDR) A Monitoring and evaluation report A REFERENCES A General A List of References A References in English Language A References in Other Languages A222 A 14