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-

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n-0

4

Oct-

04

Fe

b-

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n-0

5

Oct-

05

Fe

b-

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n-0

6

Oct-

06

Fe

b-

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n-0

7

Oct-

07

Fe

b-

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n-0

8

Oct-

08

Fe

b-

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n-0

9

Oct-

09

Fe

b-

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n-1

0

Oct-

10

Fe

b-

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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

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Jan-

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Jul-0

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Jan-

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Jul-0

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Jan-

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Jul-0

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Jan-

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Jul-0

9

Jan-

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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