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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)
SALGA Water Services
Master Class
2
• Introduction
• Methodology Followed
• Impacts and Results
• Conclusion
• Recommendations
• Acknowledgements/Contact Details
Overview
3
• 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)
Introduction
4
• 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
Introduction
5
• 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.
Introduction
6
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
Methodology
7
• 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
Methodology cont.
8
• 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)
Methodology cont.
9
IWA Water Balance
System
Input
Volume
Authorised
Consumption
Billed Authorised
Consumption
Billed Metered
Consumption
Revenue
WaterBilled Un-metered
Consumption
Unbilled Authorised
Consumption
Unbilled Metered
Consumption
Non-
Revenue
Water
Unbilled Un-metered
Consumption
Water Losses
Apparent Losses
Unauthorised
Consumption
Customer Meter
Inaccuracies
Real Losses
Leakage on Transmission
and Distribution Mains
Leakage on Overflows at
Storage Tanks
Leakage on Service
Connections up to point of
Customer Meter
10
• 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
Methodology Design
11
• 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
Methodology Design
Water Balance Components
12
• 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
Methodology Design
Water Balance Components
13
Impact and Results
Water Balance Table
Year ending
Jun-01 Jun-02 Jun-03 Jun-04 Jun-05
Water Balance Calculations
Bulk Supplykl/
Annum433,352,096 458,273,488 466,249,758 473,384,957
Water Accounted For (Billed metered,
deemed and informal)
kl/annum
278,327,940 273,590,769 298,160,447 315,182,821
% UFW Est 41% 35.8% 40.3% 36.1% 33.4%
14
Impact and Results
Water Balance Table.
Year ending
Jun-06 Jun-07 Jun-08 Jun-09 Jun-10 Jun-11
Water Balance
Calculations
Bulk Supplykl/
Annum469,030,696 489,153,637 493,039,487
505,350,244
497,925,165
525,601,237
Water Accounted
For
kl/annum
325,954,178 336,202,527 329,014,492319,625,15
8310,759,65
8322,780,69
4
% UFW 30.5% 31.3% 33.3% 36.8% 37.6% 38.6%
15
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)
0.00E+00
5.00E+06
1.00E+07
1.50E+07
2.00E+07
2.50E+07
3.00E+07
3.50E+07
4.00E+07
4.50E+07
5.00E+07
Oct-
01
Fe
b-
Ju
n-0
2
Oct-
02
Fe
b-
Ju
n-0
3
Oct-
03
Fe
b-
Ju
n-0
4
Oct-
04
Fe
b-
Ju
n-0
5
Oct-
05
Fe
b-
Ju
n-0
6
Oct-
06
Fe
b-
Ju
n-0
7
Oct-
07
Fe
b-
Ju
n-0
8
Oct-
08
Fe
b-
Ju
n-0
9
Oct-
09
Fe
b-
Ju
n-1
0
Oct-
10
Fe
b-
Ju
n-1
1
Oct-
11
Fe
b-
Months
Vo
lum
e k
l)
Bulk Water Supply (1)
Total Corrected Metered & Billed + Deemed
Total Not Billed (6 kl Free) + UFW
16
• 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
GRAPHICALDISPLAYS ARE FOR ILLUSTRATIVE PURPOSES ONLY
Impact and Results
Water Balance per Area
17
Impact and Results
UFW/NRW Metered Area
18
Impact and Results
UFW/NRW Un-metered Areas
19
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
Midrand/Ivory Park 15.9%
4,510,960
16.9%
4,794,668
32.8%
9,305,628
Sandton/
Alexandra
9.2%
8,181,009
20.6%
18,318,345
29.8%
26,499,354
Roodepoort/
Diepsloot
13.9%
8,193,296
18.0%
10,610,024
31.9%
18,803,320
JHB Central 6.3%
11,141,466
21.5%
38,022,465
27.8%
49,163,931
Soweto 15.0%
16,862,461
43.6%
49,013,553
58.6%
65,876,014
Deep South 16.6%
6,262,154
38.8%
14,636,842
55.4%
20,898,996
20
• 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
Impact and Results
Water Balance Actions
21
• 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
Impact and Results
22
Impact and Results
NRW Monitoring in Soweto
Non Revenue Water - Soweto Region
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Jul-0
1
Jan-
02
Jul-0
2
Jan-
03
Jul-0
3
Jan-
04
Jul-0
4
Jan-
05
Jul-0
5
Jan-
06
Jul-0
6
Jan-
07
Jul-0
7
Jan-
08
Jul-0
8
Jan-
09
Jul-0
9
Jan-
10
Jul-1
0
Jan-
11
Jul-1
1
Jan-
12
%
NRW (Soweto)
Linear (NRW (Soweto))
23
• 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.
Conclusion
24
• 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.
Recommendations
25
• 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
Contact Details
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