1. Urban Water Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Dresden, 2010 0 Global water aspects 1 Introduction to urban water management 2 Basics for systems description 3 Water transport 4 Matter transport 5 Introduction to water supply 6 Water extraction 7 Water purification 8 Water distribution 9 Introduction to wastewater disposal 10 Urban drainage 11 Wastewater treatment 12 Sludge treatment

2. Urban Water Chapter 8 Water distribution © PK, 2010 – page 2 8 Water distribution 8.1 Systems structure 8.2 Water transport 8.3 Water storage Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

3. Urban Water Chapter 8 Water distribution © PK, 2010 – page 3 8 Water distribution 8.1 Systems structure 8.2 Water transport 8.3 Water storage Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

4. Urban Water Chapter 8 Water distribution © PK, 2010 – page 4 CostsRedundant capacity Supply safetyResidence time Low Medium High Only in end pipes high, uni- directional flow Low, since only one way to tap limited, large diameters for fire fighting Only in end pipes high In parts long, depending on operating conditions medium, two ways to tap high; break- downs only locally effective Increased safety for fire fighting water availability High safety for fire fighting water availability, higher pressure loss Branched network Circular arrangement Meshed network Network structure

5. Urban Water Chapter 8 Water distribution © PK, 2010 – page 5 Flow throughCounterCentral HB Supply safety Pipes diameters Pressure variation Friction loss Storage renewal Control effort Flow direction Implementation Ev. not good good Low Small High Altering Flat topography Low, if 2-side supply Dep. on topography good High Medium Ev. not good High Altering low high Medium High Good Low Uni-directional economic Storage arrangement

6. Urban Water Chapter 8 Water distribution © PK, 2010 – page 6 River Purification plant Pumping station High supply region Reservoir Raw water pumping station Pressure increase station Pressure reduction valve Low supply region Purification plant Dam Pumping station Clean water storage tank Compensation tank Example of a supply region

7. Urban Water Chapter 8 Water distribution © PK, 2010 – page 7 8 Water distribution 8.1 Systems structure 8.2 Water transport 8.3 Water storage Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

8. Urban Water Chapter 8 Water distribution © PK, 2010 – page 8 Water treatment Pumping station 1 and 2 Valve 1-2 Pumping station 3 Valve 2-3 Pumping station 4 Valve 3-4 Pressure zone 4 Pressure zone 1 Pressure zone 3 Pressure zone 2 Minimum pressure Ground floor 2,0 bar per floor +0,5 bar minimum +0,35 bar Pressure zones

9. Urban Water Chapter 8 Water distribution © PK, 2010 – page 9 Little consumption high consumption 40 -100 m Pressure lines Pressure 4 - 10 bar Little consumption High consumption Supply from reservoir or pump

10. Urban Water Chapter 8 Water distribution © PK, 2010 – page 10 40 -100 m Pressure lines Little consumption High consumption Pump not operating Supply from reservoir and pump

11. Urban Water Chapter 8 Water distribution © PK, 2010 – page 11 10 -20 m Little pressure „No pressure“ Insufficient pressure

12. Urban Water Chapter 8 Water distribution © PK, 2010 – page 12 8 Water distribution 8.1 Systems structure 8.2 Water transport 8.3 Water storage Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

13. Urban Water Chapter 8 Water distribution © PK, 2010 – page 13 Compensation of variations in consumption, covering of peaks Compensation between pre and main pumping Control pressure ranges according to respective zones Safety for supply during operation disturbances Water for fire fighting (ev. separate pipes) Could serve as mixing or sedimentation tank Storage over limited time hygienic store energy Purposes of storage tanks

14. Urban Water Chapter 8 Water distribution © PK, 2010 – page 14  protection from pollution Filtration of air Temperature  constant No light (growth of algae) circulation and renewal of water (no regions with high residence time or stagnation) Smooth surface Pressure installations for cleaning Provide hygienic conditions

15. Urban Water Chapter 8 Water distribution © PK, 2010 – page 15 Compensation -between pumping and consumption -usually based on diurnal variations Safety -bridging breakdown and breakages -depending on systems size and structure Fire fighting -depending on systems size and structure - depending on potential damage Reservoir volume

16. Urban Water Chapter 8 Water distribution © PK, 2010 – page 16 Compensation  50% of average daily consumption Safety plus fire  50% of average daily consumption fighting Decrease large city supply areas with multiple independent inputs Increase small supply areas with single input Rule of thumb 0,2 to 0,5 m 3 /person Typical values for reservoir volume

17. Urban Water Chapter 8 Water distribution © PK, 2010 – page 17 Diurnal consumption variation and pumping strategies Reservoir dimensioning (i)

18. Urban Water Chapter 8 Water distribution © PK, 2010 – page 18 Diurnal consumption variation and pumping strategies; accumulated Reservoir dimensioning (ii)

19. Urban Water Chapter 8 Water distribution © PK, 2010 – page 19 Option 3 Pumping from…to6 – 16 Uhr Max. surplus |S| (%) 33,5 Max. deficit |D| (%) Option 1 0 – 24 Uhr 19,5 Option 2 20 – 6 Uhr 52 - 5,2- 18,5- 10,5 Compensation volume C = |S| + |D| (%) 24,770,544 Resulting storage volumes

20. Urban Water Chapter 8 Water distribution © PK, 2010 – page 20  Fire brigade  Insurance companies Minimum 100 m 3 For multiple independent inputs it can be reduced or even neglected Need of fire brigade: Depending on characteristics of area  0,01 to 0,06 m 3 /s  100 m 3 provide this for app. 0,5 h to 2,5 h Fire fighting

21. Urban Water Chapter 8 Water distribution © PK, 2010 – page 21 Minimum app. 40 m above supply area Large diameters  small losses  low tower High water depth  statics  distinct pressure variations  higher tower Up to a volume of 200 m 3 for one chamber Water tower (i)

22. Urban Water Chapter 8 Water distribution © PK, 2010 – page 22 inlet overflow Lift effluent Fire fighting Daily variation Fire fighting Lift Staircase Effluent Emptying Fire fighting Inlet Cables Overflow Water tower (ii)