The document summarizes a presentation on intermittent water supplies from an international conference. It discusses the causes of intermittent supply, including aging infrastructure, high demand, water scarcity from climate change, and poor management. This can create a vicious cycle of more leaks and pipe failures. The presentation recommends strategies for utilities experiencing intermittent supply such as sectorizing their network to identify high leak areas, renewing poor pipes, monitoring flows and pressures, actively detecting and fixing leaks, and ultimately achieving 24/7 water supply to improve services and management. Moving to a continuous supply provides benefits like better water quality, reduced costs, and increased revenues.

1. Intermittent Water Supplies –
An International Update
By Richard Taylor, Thomas Civil &
Environmental Consultants
h
PWC’14 - 9 September 2014

2. Background
I attended the International Water
Association (IWA) Water Loss Conference
in April 2014
A pre-conference workshop was held on
Intermittent Water Supplies (IWS)
I was aware of some IWS in the Pacific
islands and therefore thought it might be
useful to share learnings from the
conference

3. IWA Water Loss 2014
Pre-conference Workshop
Main Presenters (information used with
permission)
•Bambos Charalambous (J2C Water Ltd) -
CYPRUS
•Anand Jalakam (Jalakam Solutions) - INDIA
•Dr. Harrison Mutikanga (Kampala Water) -
AFRICA

4. What is an Intermittent Water
Supply?
Definition
Intermittent water supplies arise when
water production for a water supply
network is insufficient to supply
customers 24 hours a day, 7 days a
week, or, when the water supply is
intentionally shut down to save water
(and/or power).

5. Bambos Charalambous – IWA Rep
PP Slide used with permission - courtesy of Bambos Charalambous

6. Bambos - Introduction to IWS
PP Slide used with permission - courtesy of Bambos Charalambous

7. Bambos – Introduction to IWS
PP Slide used with permission - courtesy of Bambos Charalambous

8. Bambos – Charalambous - CYPRUS
PP Slide used with permission - courtesy of Bambos Charalambous

9. Bambos Charalambous - CYPRUS
PP Slide used with permission - courtesy of Bambos
Charalambous

10. Bambos Charalambous - CYPRUS
PP Slide used with permission - courtesy of Bambos
Charalambous

11. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

12. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

13. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

14. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

15. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

16. Anand Jalakam – INDIA
PP Slide used with permission - courtesy of Anand Jalakam

17. Harrison Mutikanga - AFRICA
PP Slide used with permission - courtesy of Harrison Mutikanga

18. Harrison Mutikanga - AFRICA
PP Slide used with permission - courtesy of Harrison Mutikanga

19. Harrison Mutikanga - AFRICA
Water Scarcity
•Scarcity from poor management (high
leakage &wastage, poor O & M practices,
governance issues – corruption, etc)
•Economic scarcity (financial constraints
to expand infrastructure to meet increasing
demand; poor planning & demand
forecasting)
•Absolute scarcity (insufficient quantity at
the source – exacerbated by climate
change)

20. Harrison Mutikanga - AFRICA
PP Slide used with permission - courtesy of Harrison Mutikanga

21. SUMMARY OF ISSUES
• Causes of Intermittent Water Supply
(IWS)
• Implications of IWS – The Vicious Cycle
• Strategy for Eliminating IWS
• Benefits of 24 x 7 Water Supply

22. Harrison Mutikanga - AFRICA
PP Slide used with permission - courtesy of Harrison Mutikanga

23. Dewi Rogers (ITALY) – Paper
‘Intermittent suppelyn antidt lwehdy :leakage is the root
cause’.
Cause of IWS:
Experience has shown that IWS is invariably the
direct consequence of high leakage. Without
adequate monitoring and control, leakage
unknowingly creeps up to the point where the
reservoir runs dry. At that point the vicious circle of
intermittent supply starts, which, though
implemented to try and reduce the consequence of
the problem, invariably ends up exacerbating the
cause.

24. The Vicious Cycle of IWS (1)
Harrison Mutikanga - AFRICA
PP Slide used with permission - courtesy of Harrison Mutikanga

25. The Vicious Cycle of IWS (2)
Anand Jalakam - INDIA
PP Slide used with permission - courtesy of Anand Jalakam

26. The Vicious Cycle of IWS - Summary:

27. Summary of Causes of IWS:
•Deteriorating infrastructure
•Growth in total demand (including leakage)
•Water scarcity - exacerbated by climate
change
•Economic scarcity – financial constraints
•Poor management – allowing IWS to occur
•Power supply shortages/ rationing

28. Implications of IWS – Customer
Related:
•Conflict between various water users
•Inconvenience to customers
•Customer meters may over-read (due to air)
•Low supply pressures
•Deterioration of water quality
•Large number of customer complaints
•High coping costs for customers (for tanks,
pumps etc)

29. Implications of IWS – Demand
Related:
•Water wastage – customers will leave taps on
so tanks will fill
•Increased difficulty in detecting and fixing
leaks (with low/ no pressure)
•Increased mains failures due to pressure
surges and the entry/exit of air
•Ineffective supply and demand management
due to measurement (metering) difficulties

30. Implications of IWS – Infrastructure
Related:
•Inefficient operations and network
maintenance - more manpower is used for
frequent valve operation etc.
•Meter malfunctioning and accelerated wear
and tear
•Damage to pipes and fittings from the entry/
exit of air causing large and dangerous
pressure fluctuations, greater than the pipe
can bear

31. Implications of IWS – Financial
Impacts on the Water Utility due to:
•Reduction in water sales
•Higher costs due to staff overtime and the
cost of pipe repairs
•Increase in (the cost of) leakage
•Increased costs due to general network
deterioration caused by IWS

32. Strategy for Eliminating IWS (1)
Harrison Mutikanga - AFRICA
Is it possible to achieve 24 x 7 water
supply & sustainably reduce NRW in
intermittent supply systems?
The best strategy is to progressively
move a few areas to continuous supply
and introduce NRW reduction
interventions such as Minimum Night
Flow monitoring & Active Leakage
Control

33. Strategy for Eliminating IWS (2)
Dewi Rogers - ITALY
Recommended strategy:
•Define water loss (allowing for IWS)
•Build and utilise network model
•Create zones (sectors) with pressure
management and metering
•Eliminate the largest leaks
•Ongoing monitoring and management
•Renew watermains in very poor condition

34. Strategy for Eliminating IWS (3)
Dewi Rogers - ITALY
Recommended strategy continued:
The division of the network into sectors
yields three important benefits:
1.To identify parts of the network with the
most leakage;
2.To facilitate the location of leaks; and
3.To allow the lower leakage level to be
maintained in the future.

35. Sectorizing a Water Supply Network

36. Recommended Strategy for
Eliminating IWS (1)
1. Start with selecting one or two areas
with IWS
2. Assess the condition of the network
(pipes, fittings, connections, meters)
3. Renew watermains/ connections in very
poor condition
4. Design network sectorizing (metering)
and pressure management

37. Recommended Strategy for
Eliminating IWS (2)
5. Embark on a public communications
programme
6. Commit to 24/7 supply (if feasible) by
pumping 24/7 in a low demand period of
the year
7. Implement network sectorizing
(metering) and pressure management
8. Introduce daily monitoring of flows and
pressures using GSM data

38. Flow and Pressure Control Installation

39. Recommended Strategy for
Eliminating IWS (3)
9. Carry out an intensive leak detection
and repair programme
10.Monitor Minimum Night Flows on an
ongoing basis (using daily GSM data)
11.Continue with active leak detection and
repair, and with network renewals until
the situation is under control
12.Report regularly on NRW and water loss
in the zone

40. Monitoring of Minimum Night Flows
120
100
m)
(HGL) 80
(Line 60
Grade Hydraulic 40
20
0
Hours 0 6 12 18 24 30 36 42 48
120
100
80
60
40
20
0
Flow (l/s)
112 m
91 m
Q Min = 10.9 l/s Q Min = 7.3 l/s

41. Benefits of 24 x 7 Water Supply (1)
• Better quality water for public health
• Significantly better service to customers
• Avoids customers spending money on
‘coping costs’
• Reduces burden on water resources – by
allowing more effective leakage
management (continuous supply for flow
and pressure control), and by reducing
water wastage from overflowing private
tanks etc.

42. Benefits of 24 x 7 Water Supply (2)
• Reduces maintenance costs – less staff
time operating valves, fewer number of
burst mains/connections
• Possibly lower power and water
production costs (if pumping less water
once the situation is under control)
• Water revenue from metered
consumption may increase as customers
pay for what they consider is good
service, and for a fair metered volume

43. The Result of all this?
HAPPY CUSTOMERS
HAPPY WATER ENGINEERS

44. Bambos Charalambous (Cyprus) –
Forming an IWA Task Group for
“INTERMITTENT WATER SUPPLIES”
Purpose: Establish an international group of
experts to develop a manual of tools and
methodologies for dealing with IWS.

45. Thank you
Any questions?