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Water Services Management

Water Services Management

David Stephenson

(2005)

Additional Information

Book Details

Abstract

Water services include water supply, sewerage and stormwater drainage. The facilities needed for these services are pipelines, reservoirs and treatment works; but the service goes beyond the infrastructure. It includes economics, billing, and business management. Although these services exist in every city, being advanced by the growing use of automation and information technology, costs are also increasing without many consumers seeing increased benefits. Customer service is therefore becoming important to the industry. Water Services Management is intended to educate engineers to manage and improve water services, rather than simply designing and constructing treatment works and distribution systems. The text covers water supply and drainage from the hydraulic and economic points of view, and while design and construction practices are reviewed, the focus of the book is on improving existing systems to turn the emerging industry into an attractive business. Topics covered include: Potable water supply, sewerage and stormwater drainage.         Hydraulic management: storage, peak flow attenuation and pumping.         Water quality: standards, pollution control and treatment.         Infrastructure management: rehabilitation, reconstruction, upgrading and maintenance.         Economic efficiency: asset management, privatization, and risk analysis.         Improving economic viability via efficient use of energy and construction project management. Characteristics encountered in developing countries are also considered, including: Low cost sanitation, water supply standards and off-grid energy sources.         Capacity building and appropriate technologies.         Financing, operation and benchmarking.

Table of Contents

Section Title Page Action Price
Contents 6
Preface 16
Index 424
1.0 Water sources and quality 20
1.1\tAVAILABILITY OF FRESH WATER 20
1.1.1\tSurface water 21
1.1.2\tGroundwater 24
1.1.2.1\tSprings 25
1.1.2.2\tWells and boreholes 25
1.1.2.3\tHand-dug wells 25
1.1.2.4\tTube wells 27
1.1.2.5\tBoreholes 27
1.1.3\tSiting of wells and boreholes 27
1.1.4\tDetermination of yield 28
1.2\tRAINWATER 29
1.3\tWASTEWATER AND RECYCLING 30
1.4\tSEAWATER OR SALINE WATER 31
1.5\tWATER POLLUTION 31
1.5.1 Protection of public health 32
1.5.2\tPollution risk assessment and management 32
1.6\tINTERNATIONAL STANDARDS AND CRITERIA 33
1.6.1\tMicrobiological determinants 33
1.6.2\tChemical and physical determinants 34
1.6.3\tOrganic pollution 36
1.6.4\tStability of water supplies 37
1.7 WATER TREATMENT 37
1.8\tREFERENCES 41
2.0 Urban water supply 42
2.1 WATER USE 42
2.1.1\tVolumes required 43
2.1.2\tPlanning basis 44
2.1.3\tPeak factors 47
2.1.4\tPressure requirements 48
2.2\tRESERVOIR STORAGE REQUIREMENTS 49
2.2.1\tElevated storage and pumps 49
2.2.2 Balancing volume 50
2.2.3\tOther storage reservoirs 50
2.3\tPIPE FLUID MECHANICS 51
2.3.1\tThe fundamental equations of fluid flow 52
2.4\tFLOW HEAD LOSS RELATIONSHIPS 53
2.4.1\tEmpirical flow formulae 53
2.4.2\tRational flow formulae 54
2.5 WATER HAMMER AND FLOW CONTROL 58
2.5.1\tValves and other fittings 60
2.6\tPIPELINE OPTIMISATION 61
2.7\tOPTIMUM RESERVOIR SIZES 64
2.8\tPUMP CHARACTERISTIC CURVES 66
REFERENCES 66
3.0 Water demand management and loss control 68
3.1\tCONTROLLING WATER USE 68
3.2\tECONOMIC THEORY OF SUPPLY AND DEMAND 71
3.2.1\tEffect of metering 73
3.2.2\tManagement by use of tariffs 74
3.3\tTIMING 76
3.3.1\tLong-term (planning and design) 77
3.3.2\tOperational time-frame 78
3.3.3\tCrisis management 79
3.3.3.1\tPenalties or punitive tariffs 80
3.3.3.2\tPurchase system 80
3.3.3.3\tShortfall surcharge 80
3.3.4\tNotes on management by use of tariffs 80
3.4\tTHE COST OF WATER 81
3.4.1\tFuture trends 86
3.5\tVALUE OF WATER 86
3.6\tLOSS CONTROL 87
3.7\tWATER HARVESTING 90
REFERENCES 90
4.0 Sewerage 92
4.1\tFLOW IN CIRCULAR DRAINS 92
4.1.1\tManning equation 92
4.1.2\tNon-circular cross sections 93
4.1.3\tUniform flow in part-full circular pipes 94
4.2\tDRAINAGE NETWORK OPTIMISATION 96
4.2.1\tThe variables 96
4.2.2\tDynamic programming for optimising compound pipes 99
4.3\tDESIGN OF SEWERS 102
4.3.1\tSewer flows 104
4.3.2\tConstruction 104
4.3.3\tAccess and ventilation 107
4.3.4\tComputer Design and Grading 108
REFERENCES 110
5.0 Sewer leakage and rehabilitation 111
5.1\tSTORMWATER AND GROUNDWATER INGRESS 111
5.2\tPROBLEMS IN WASTE WATER COLLECTION SYSTEMS 112
5.3\tDETERMINING EXTRANEOUS FLOWS 113
5.3.1\tInfiltration into sewers 113
5.3.2\tInflow into sewers 114
5.3.3\tDetermination of ingress events 114
5.4\tIMPACT OF STORMWATER AND GROUNDWATER INGRESS 116
5.4.1\tWastewater Treatment Works (WWTW) 116
5.5\tREDUCING STORMWATER INFLOW 119
5.5.1\tLocal structure improvements 119
5.5.2\tEffective utilisation of existing storage in sewerage systems 119
5.5.3\tPro-active maintenance 120
5.5.4\tOverflows or redirection of flows within a system 120
5.5.5\tHolding ponds 120
5.5.6\tEnhancement of sewer network 120
5.6\tANCILLARY SYSTEMS 121
5.6.1\tPumping systems 121
5.6.2\tVacuum systems 121
5.6.3\tProtective structures 122
5.6.4\tPurchase of land/properties 122
5.7 MANAGEMENT OF INGRESS 123
5.7.1 Preventative measures 124
5.7.2\tRemedial measures 125
5.8\tALTERNATIVE METHODS FOR REMEDIATION 125
5.8.1\tRehabilitation methods 125
5.8.1.1\tNonstructural lining 125
5.8.1.2\tStructural lining 126
5.8.2\tReplacement methods 127
5.9\tBENEFIT-COST ANALYSIS 130
5.9.1\tCost-effectiveness analysis 130
5.10\tSEWER MAINTENANCE 132
5.10.1\tPreliminary analysis 132
5.10.2 Sewer testing 133
5.10.3\tCorrosion of sewers 134
5.10.4\tRehabilitation of manholes and sumps 136
5.11\tREFERENCES 136
6.0 Alternative urban drainage systems 138
6.1\tINTRODUCTION 138
6.2\tDRAINAGE STREAMS 139
6.2.1\tGrey water 142
6.2.2\tStormwater 142
6.2.3\tSewerage 144
6.3\tCASE STUDY IN ALEXANDRA TOWNSHIP 146
6.4\tSYSTEM MASS BALANCES 147
6.5\tDOMESTIC MASS BALANCE 147
6.6\tREFERENCES 149
7.0 Wastewater treatment 150
7.1\tSEWAGE QUALITY 150
7.2\tTREATMENT PROCESSES 152
7.3\tAPPROPRIATE SANITATION 158
7.4\tCATEGORIES OF SANITATION SYSTEMS 159
7.4.1\tGroup 1: No water added – Requiring conveyance for treatment at central works 159
7.4.1.1\tChemical toilets 159
7.4.2\tGroup 2: No water added – no conveyance (treatment or partial treatment on site before disposal) 161
7.4.2.1\tVentilated improved pit (VIP) toilet 161
7.4.2.2\tVentilated improved double-pit (VIDP) toilet 162
7.4.2.3\tVentilated vault (VV) toilets 163
7.4.2.4\tContinuous composting (CC) toilets 163
7.4.3\tGroup 3: Water added – requiring conveyance (treatment at a central works) 164
7.4.3.1\tFull water-borne sanitation 164
7.4.3.2\tFlushing toilet with conservancy tank 165
7.4.3.3\tSettled sewage systems 165
7.4.4\tGroup 4: Water added – no conveyance (treatment or partial treatment on-site before disposal) 166
7.4.4.1\tFlushing toilet with septic tank and subsurface soil absorption system 167
7.4.4.2\tLow-flow on-site sanitation systems (LOFLOs) 167
7.5\tFACTORS AFFECTING CHOICE OF SANITATION 169
7.6\tREFERENCES 174
8.0 Stormwater drainage 176
8.1\tINTRODUCTION 176
8.2\tTHE RATIONAL METHOD 177
8.3\tLLOYD-DAVIES METHOD 182
8.4 STEP METHOD 183
8.5\tTIME-AREA DIAGRAM AND ISOCHRONAL METHODS 186
8.6\tTANGENT METHOD AND MODIFICATIONS 188
8.7\tKINEMATIC METHOD 191
8.7.1\tTime of concentration for a plain 192
REFERENCES 194
9.1\tDESIGN ALTERNATIVES 195
9.2\tSTORMWATER MANAGEMENT PRACTICES 197
9.2.1\tSafety factors 199
9.3\tDETENTION AND RETENTION PONDS 200
9.4 PERCOLATION BASINS 205
9.4.1\tEffect of holding on water quality 206
9.4.2\tOn-site detention 206
9.5\tSTRUCTURES TO CONTAIN RUNOFF 207
9.5.1\tParking-lot storage 207
9.5.2\tRooftop detention 207
9.5.3 Combined sewers 207
9.6\tOVERLAND AND CHANNEL RETARDATION 208
9.6.1\tDual drainage 209
9.7\tFLOOD MANAGEMENT 209
9.8 RESERVOIR ROUTING METHODS 214
9.9\tFLOOD RISK ANALYSIS 217
9.10\tFLOOD PLAIN MANAGEMENT 218
9.10.1\tHazards associated with flooding 218
9.11\tINTEGRATED FLOOD PLAIN MANAGEMENT 220
9.11.1\tChannel confinement 221
9.11.2\tAnti-flooding devices 222
REFERENCES 222
10.0 Drainage structures 224
10.1 HYDRAULICS OF BRIDGES 224
10.1.1\tFlow through gap 226
10.1.2 Surface profile 227
10.1.3 Drop in water level 233
10.1.4\tComplex structures 235
10.1.5\tFlow over an embankment 235
10.1.6\tInundation of bridge 237
10.1.7\tErosion due to overflow 238
10.2\tCULVERT HYDRAULICS 238
10.2.1\tEconomic design 238
10.2.2\tPrinciple of controls 239
10.2.3\tHydraulic profiles 240
10.2.4\tInlet Design 242
10.2.5 Inlet control equations for box culverts 244
10.2.6 Circular pipe culverts 245
10.2.7\tOutlet Control 247
10.2.8 Balanced design 248
10.3\tREFERENCES 249
11.0 Asset management 251
11.1 INTRODUCTION 251
11.2 ASSETS 252
11.3\tBENEFITS OF ASSET MANAGEMENT 254
11.4\tBEST PRACTICE 255
11.4.1\tReviews of world practices 256
11.4.2 United Kingdom 258
11.4.3 Australia and New Zealand 260
11.4.3.1\tThe Australian asset management (AM) process 260
11.4.3.2\tThe New Zealand asset management (AM) process 261
11.5\tDATA MANAGEMENT 264
11.6\tMETHODOLOGY FOR AMPS 264
11.6.1 Information systems 265
11.6.2 Asset management plans 266
11.6.2.1\tWhat should a typical Asset Management Plan comprise? 266
11.6.2.2\tWhat should a typical Asset Management Plan deal with? 266
11.6.3\tBenefits from implementing an Asset Management programme 268
11.6.4\tTypes of asset management plans 268
11.7\tLIFE CYCLE ASSET MANAGEMENT 270
11.7.1 \tLife cycle costing 271
11.7.2\tThe life of a works 273
11.7.3\tEconomic evaluation 274
11.8 ASSET MANAGEMENT REGISTERS 276
11.8.1\tNational standard for asset registers 276
11.8.2\tRequirements of an asset register 277
11.8.3\tComponents of a national standard for asset registers 277
11.8.4\tSelection of assets on register 278
11.8.5\tMinimum set of information to be recorded 278
11.8.6\tRecording the changes to assets 279
11.8.7\tCapturing the data 280
11.9\tSYSTEM DEFINITION 280
11.9.1\tAsset identification and classification 281
11.10\tREFERENCES 281
12.0 Privatisation 283
12.1\tINTRODUCTION 283
12.2\tECONOMIC REFORM 286
12.3\tCONCESSIONS 287
12.3.1\tDefinition of a concessionary contract 288
12.4\tFORMS OF PARTNERSHIP EVALUATED 291
12.4.1\tFull Privatisation 291
12.4.2\tConcession 291
12.4.3\tLease Contract 292
12.4.4\tManagement Contract 292
12.4.5\tService Contract 292
12.4.6\tCorporatisation 292
12.4.7\tPublic-Public Partnerships 293
12.4.8\tBOOT and BOT Projects 293
12.4.9\tMunicipal Debt Issuance 294
12.4.10 Private Consultants 294
12.5\tMUNICIPAL CHARACTERISTICS 294
12.6\tPRIVATE AND PUBLIC INSTITUTIONAL ROLES 296
12.6.1\tCase study – Balfour municipality 297
12.6.2\tAnalysis of municipal situation 297
12.6.3\tImmediate capital expenditure requirements 298
12.6.4\tAge, condition, value relationship of existing assets 299
12.6.5\tCapital available 299
12.6.6\tMunicipal income and expenses 301
12.6.7\tCost of service provision and level of cost recovery 301
12.6.8\tWater and sanitation staff 302
12.6.9 System efficiency, quality and service 302
12.6.10 Results of analysis 303
12.7\tSELECTION OF BEST FORM OF PUBLIC PRIVATE PARTNERSHIP 304
12.8\tREFERENCES 305
13.0 Probability and risk 307
13.1\tHYDROLOGICAL UNCERTAINTY 307
13.1.1\tProbability distributions 308
13.1.2\tAnalysis of records 312
13.1.3\tConfidence bands 315
13.1.4\tDesign discharge 316
13.1.5\tSpread risk 316
13.1.5.1\tExample 316
13.2 RELATIONSHIP BETWEEN PROBABILITY, RISK AND HAZARD 319
13.2.1\tDefinitions 319
13.3\tSPILLWAY DESIGN FLOOD 319
13.4 RISK FACTOR IN WATER SUPPLY 320
13.4.1\tTechnological risks 321
13.4.2 Financial risk 321
13.4.3\tNatural and external factors 321
13.5\tPLANNING TO MINIMIZE EFFECTS OF RISK 322
13.5.1\tEconomic risk 323
13.5.2\tEffect of uncertainty in demand estimates 326
13.5.3\tSouth African case study 329
13.6\tRELIABILITY OF WATER SUPPLY NETWORKS 331
13.7\tVULNERABILITY 332
13.8\tREFERENCES 335
14.0 Economics and financing water services 337
14.1 SOURCES OF FINANCE 337
14.2\tBENEFITS OF RURAL WATER SUPPLIES 340
14.2.1\tJustification for rural water supplies 342
14.2.2\tEvaluation methods 343
14.2.3 Study of water collecting time 344
14.3\tRESULTS OF FIELD SURVEY 344
14.3.1\tHealth benefits of water supply 345
14.3.2\tEducational benefits 346
14.3.2.1\tAnalysis of school results 346
14.3.2.2\tComparison of school pass rate – 2 districts with and without water supply 347
14.3.2.3\tEducational benefit 348
14.4\tSTUDY OF HOUSEHOLD ECONOMY 348
14.4.1\tAverage household monthly income 349
14.4.2\tMicro survey of household economies 349
14.5\tREFERENCES 352
15.0 Development issues 353
15.1 BACKGROUND 353
15.1.1\tWater supply problems 354
15.1.1.1\tWater has often been considered as a free resource, or a “gift from heaven” 354
15.1.1.2\tWater is often considered as part of the national heritage 355
15.1.1.3\tWater represents a public health issue 355
15.1.1.4\tWater represents an important social concern 355
15.1.2\tPopulation of developing countries 355
15.1.3 Financial limitations 357
15.1.4\tInstitutional problems 359
15.2 WATER QUALITY AND HEALTH 360
15.2.1\tWater-related diseases 361
15.2.1.1\tWaterborne diseases 361
15.2.1.2\tWater-washed diseases 361
15.2.1.3\tWater-based diseases 361
15.2.1.4\tWater-related insect vectors 361
15.2.1.5\tShortage of water 361
15.2.2\tWater quality standards 363
15.3\tLEVEL OF SERVICE 363
15.4\tALTERNATIVE SYSTEMS 366
15.5 PROBLEMS IN SUPPLY 367
15.5.1\tPayment 368
15.6\tCOMMUNITY PARTICIPATION 369
15.6.1\tAffordability 370
15.7\tPOLICY 371
15.8 DEVELOPING PEOPLE 371
15.9 THE FUTURE 374
15.10\tREFERENCES 375
16.0 The energy factor 376
16.1 PUMPING ENERGY 376
16.1.1\tProgramming pumping systems 378
16.1.2\tModel formulation 381
16.1.3\tOperating cost components 384
16.1.4\tPredicting consumer demands 385
16.2\tENERGY INTENSIVE VERSUS CAPITAL INTENSIVE PROJECTS 386
16.3\tPUMPING SEWAGE 386
16.4\tHYDROPOWER 387
16.5\tSOLAR-HYDRO HYBRID SYSTEM FOR RAPS 387
16.5.1\tHybrid energy systems for rural communities 388
16.5.2\tDevelopment of alternative energy sources 389
16.6\tREFERENCES 391
17.0 Project management 392
17.1\tINTRODUCTION 392
17.2 CONTRACT PROCEDURES AND DOCUMENTS 393
17.3 PROJECT STAGES 393
17.4\tMANAGEMENT TECHNIQUES 394
17.5\tRESOURCE MANAGEMENT 399
17.6 COMMUNICATION 400
17.7\tQUALITY CONTROL 400
17.8\tHAZARDS RELEVANT TO WATER SERVICES 401
17.9\tREFERENCES 405
18.0 Organisation and operation 406
18.1 QUALITY CONTROL 408
18.2\tCONTAMINATION 409
18.3\tFINANCIAL MANAGEMENT 410
18.4\tHUMAN RESOURCE MANAGEMENT 411
18.4.1\tHuman resources and training 412
18.5\tMAINTENANCE SCHEDULING 413
18.6\tEMERGENCY SUPPLIES 413
18.7\tLEGAL 414
18.7.1\tWater law 414
18.7.2\tBylaws 416
18.7.3\tInspectorates 417
18.7.4\tRegulation 417
18.7.5\tCompetition 418
18.8 SEWER MAINTENANCE DATA PROCESSING 419
18.8.1Application 419
18.8.2 Processing of sewer maintenance data 420
18.9\tREFERENCES 422