SALGA Water Services
Master Class
Management via Water Balance
(Using the water balance as a tool to direct
interventions and monitor performance of
interventions)
Presented by: Etienne Hugo (GM: Operations)
Overview
• Introduction
• Methodology Followed
• Impacts and Results
• Conclusion
• Recommendations
• Acknowledgements/Contact Details
2
Introduction
• Water Balance is to account for water being supplied into the water
reticulation network. (UFW/NRW calculation)
• Unaccounted for Water was identified as a major concern for the City
of Johannesburg in 1999
• Unaccounted for Water was estimated at 41%. Thus no official water
balance exist at the time.
• The challenge was to develop a reliable water balance for
benchmarking purposes. (Global and Regional)
3
Introduction
• Water Balance template was developed using the IWA water balance
as a guideline.
• Areas were ring fenced to enable area based water balances.
• Reliable information obtained for:
– Bulk Supply Volumes
– Billing Volumes
– Other metered Volume
4
Introduction
• The first goal was to compile a global water balance. (Entire CoJ area)
• Secondly was to split the global into regional/area water balances.
• Third goal was to use the water balance to guide intervention for the
reduction of UFW as well as Water Demand.
• The fourth goal was to use the water balance as a monitoring tool on
the effectiveness of interventions.
5
Methodology
Area
• 65 km North to South
• 35 km East to West
• 1,625 km2
• 6 Operational Regions
- Midrand/Ivory Park
-Sandton/Alexandra
- JHB Central
- Roodepoort/Diepsloot
- Soweto
- Deep South
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Methodology cont.
• Area consist of 750 000 domestic, commercial and industrial
customers.
• 550 000 water connections are supplying water to customers.
• Estimated consumer population of 4 million
• Average daily demand of 1 400Ml
• Total Water Network Length of 11 800km
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Methodology cont.
• Water Balance to be done on a monthly basis.
• Results is reviewed continuously
• First the overall water balance is analyzed followed by the regional or
area based water balance.
• IWA Water Balance Used as the foundation in all levels of water
balance.
• Cost of the project to develop and maintain the water balance is
covered under operational expenses and is approximately R500 000
per annum.
• Cost of interventions monitored is to the value of R800 million (Soweto
Project)
8
IWA Water Balance
Billed Metered
Consumption
Billed Authorised
Consumption
Billed Un-metered
Consumption
Revenue
Water
Unbilled Metered
Consumption
Authorised
Consumption
Unbilled Authorised
Consumption
Unbilled Un-metered
Consumption
Unauthorised
Consumption
System
Input
Volume
Apparent Losses
Customer Meter
Inaccuracies
Leakage on Transmission
and Distribution Mains
Water Losses
Real Losses
Leakage on Overflows at
Storage Tanks
Leakage on Service
Connections up to point of
Customer Meter
NonRevenue
Water
9
Methodology Design
•
Johannesburg Water Methodology
- In Johannesburg Water, the following methodology is followed for the water balance and to calculate
calculate UFW:
(Volume of bulk water purchased)
Less
(Total volume billed by City of Johannesburg)
Less
(Total volume billed by Johannesburg Water)
Less
(Total volume sales through Pre-paid)
Less
(Total deemed consumption)
Less
(Not billed and accounted for)
- The UFW ratio is then the result of the above calculation divided by the volume of bulk water
purchased
10
Methodology Design
Water Balance Components
• Bulk Water Purchased
- JW predominantly purchases its water from Rand Water
- This information is obtained via bulk meter reads which is provided by
Rand Water
• Volume Billed
- City of Johannesburg: Volume of metered water billed (Accounts still with
the City)
- Johannesburg Water: Volume of metered water billed (Accounts controlled
by JW – Transferring this back to the City starting 2009)
• Deemed Consumption
- Tariffs are levied for either 10kl or 20kl per stand
- Typical deemed consumption areas are Soweto, Orange Farm and
Alexandra
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Methodology Design
Water Balance Components
• Not billed and accounted for
- This represents the volume of water supplied to informal settlements
- Obtained by reading bulk meters supplying the settlements
• Pre-Paid sales
- This represents the volume of water supplied to consumers through pre
payment
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Impact and Results
Water Balance Table
Year ending
Jun-01
Water Balance
Calculations
Jun-02
Jun-03
Jun-04
Jun-05
Bulk Supply
kl/
Annum
433,352,096
458,273,488
466,249,758
473,384,957
Water
Accounted
For (Billed
metered,
deemed and
informal)
kl/
annum
278,327,940
273,590,769
298,160,447
315,182,821
35.8%
40.3%
36.1%
33.4%
% UFW
Est 41%
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Impact and Results
Water Balance Table.
Year ending
Water
Balance
Calculations
Jun-06
Jun-07
Jun-08
Jun-09
Jun-10
Jun-11
Bulk Supply
kl/
Annum
469,030,696
489,153,637
493,039,487
505,350,24
4
497,925,16
5
525,601,23
7
Water
Accounted
For
kl/
annum
325,954,178
336,202,527
329,014,492
319,625,15
8
310,759,65
8
322,780,69
4
30.5%
31.3%
33.3%
36.8%
37.6%
38.6%
% UFW
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Impact and Results
Water Balance Table
Water Balance Graph - Edited
3 Month Moving Average
Total Corrected Metered & Billed + Deemed
Total Not Billed (6 kl Free) +UFW
(Bulk supply lagged by one month)
Bulk Water Supply (1)
Total Corrected Metered & Billed + Deemed
Total Not Billed (6 kl Free) + UFW
5.00E+07
4.50E+07
3.50E+07
3.00E+07
2.50E+07
2.00E+07
1.50E+07
1.00E+07
5.00E+06
Months
Feb-
Oct-11
Jun-11
Feb-
Oct-10
Jun-10
Feb-
Oct-09
Jun-09
Feb-
Oct-08
Jun-08
Feb-
Oct-07
Jun-07
Feb-
Oct-06
Jun-06
Feb-
Oct-05
Jun-05
Feb-
Oct-04
Jun-04
Feb-
Oct-03
Jun-03
Feb-
Oct-02
Jun-02
Feb-
0.00E+00
Oct-01
Volume kl)
4.00E+07
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Impact and Results
Water Balance per Area
• Next slides is a visual representation of:
- UFW with the separation between commercial and physical losses in
metered areas
- UFW with the separation between commercial and physical losses in
deemed consumption / un-metered areas.
NOTE:
THE VOLUMES AND LOSSES PERCENTAGES INDICATED ON THE
GRAPHICAL
DISPLAYS ARE FOR ILLUSTRATIVE PURPOSES ONLY
16
Impact and Results
UFW/NRW Metered Area
17
Impact and Results
UFW/NRW Un-metered Areas
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Impact and Results
Water Balance Actions
• The following ratios estimated as contributing to the UFW over the
full year per Operational Region:
Physical Losses
Commercial Losses
UFW
15.9%
16.9%
32.8%
4,510,960
4,794,668
9,305,628
Sandton/
9.2%
20.6%
29.8%
Alexandra
8,181,009
18,318,345
26,499,354
13.9%
18.0%
31.9%
8,193,296
10,610,024
18,803,320
6.3%
21.5%
27.8%
11,141,466
38,022,465
49,163,931
15.0%
43.6%
58.6%
16,862,461
49,013,553
65,876,014
16.6%
38.8%
55.4%
6,262,154
14,636,842
20,898,996
Midrand/Ivory Park
Roodepoort/
Diepsloot
JHB Central
Soweto
Deep South
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Impact and Results
Water Balance Actions
• Since the area water balance indicated that 69% of losses occur in
un-metered areas.
• Dedicated programme was launched: Operation Gcin’amanzi
(Save Water) now Soweto Infrastructure Upgrade Project
• Objective of this programme are:
- Reduce UFW in un-metered areas
- Reduce Water Demand
20
Impact and Results
• Soweto Infrastructure Project (Operation Gcin’A Manzi)
– Rehabilitation of water network
– Improve level of service (Increase pipe diameter)
– Reduction of consumer demand (Retrofitting)
– Educate consumers and create awareness
21
Impact and Results
NRW Monitoring in Soweto
Non Revenue Water - Soweto Region
80.0
70.0
60.0
40.0
NRW (Soweto)
Linear (NRW (Soweto))
30.0
20.0
10.0
0.0
Ju
l-0
1
Ja
n02
Ju
l-0
2
Ja
n03
Ju
l-0
3
Ja
n04
Ju
l-0
4
Ja
n05
Ju
l-0
5
Ja
n06
Ju
l-0
6
Ja
n07
Ju
l-0
7
Ja
n08
Ju
l-0
8
Ja
n09
Ju
l-0
9
Ja
n10
Ju
l-1
0
Ja
n11
Ju
l-1
1
Ja
n12
%
50.0
22
Conclusion
• Water Balance is useful to benchmark in that water losses can
be quantified.
• Water Balance is an effective tool to guide and focus
interventions to be more effective. (High loss areas can be
identified easier)
• Water Balance is an effective tool to measure performance as
well as progress of interventions related to water losses.
23
Recommendations
• Water Balance components must be clearly defined and
reliable volume based data must be available.
• Good to use an international acceptable standard (i.e.IWA)
which the makes benchmarking easier between entities.
• When water balances are done in areas it should be properly
ring fenced.
• Water balance must be done and evaluated on a frequent
basis.
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Contact Details
• Mbalie Matiwane
Physical Loss Manager JW
(011) 688 1422
mbalie.matiwane@jwater.co.za
• Etienne Hugo
General Manager: Operations
(011) 688 6587
etienne.hugo@jwater.co.za
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