Nutrition Journal Weight, physical activity and dietary behavior change in young mothers: short term results of the HeLP-her cluster randomized controlled trial

Catherine B Lombard
Amanda A Deeks
Kylie Ball firstname.lastname@example.com
School of Exercise and Nutrition Sciences
Deakin University
Australia

Damien Jolley firstname.lastname@example.com
School of Public Health and Preventive Medicine
Monash Institute of Health Services Research
Monash University
Australia

Helena J Teede
Jean Hailes

School of Public Health and Preventive Medicine
Foundation Research Unit
Monash University
Australia

Nutrition Journal Weight, physical activity and dietary behavior change in young mothers: short term results of the HeLP-her cluster randomized controlled trial
10.1186/1475-2891-8-17BioMed Central Page 1 of 9 (page number not for citation purposes) Research * Corresponding author
Background: Preventing weight gain rather than treating established obesity is an important economic and public health response to the rapidly increasing rates of obesity worldwide. Treatment of established obesity is complex and costly requiring multiple resources. Preventing weight gain potentially requires fewer resources to reach broad population groups, yet there is little evidence for successful interventions to prevent weight gain in the community. Women with children are an important target group because of high rates of weight gain and the potential to influence the health behaviors in family members.Methods:The aim of this cluster randomized controlled trial was to evaluate the short term effect of a community-based self-management intervention to prevent weight gain. Two hundred and fifty mothers of young children (mean age 40 years ± 4.5, BMI 27.9 kg/m 2 ± 5.6) were recruited from the community in Melbourne, Australia. The intervention group (n = 127) attended four interactive group sessions over 4 months, held in 12 local primary schools in 2006, and was compared to a group (n = 123) receiving a single, non-interactive, health education session. Data collection included self-reported weight (both groups), measured weight (intervention only), self-efficacy, dietary intake and physical activity.Results: Mean measured weight decreased significantly in the intervention group (-0.78 kg 95% CI; -1.22 to -0.34, p < 0.001). Comparing groups using self-reported weight, both the intervention and comparison groups decreased weight, -0.75 kg (95% CI; -1.57 to 0.07, p = 0.07) and -0.72 kg (95% CI; -1.59 to 0.14 p = 0.10) respectively with no significant difference between groups (-0.03 kg, 95% CI; -1.32 to 1.26, p = 0.95). More women lost or maintained weight in the intervention group. The intervention group tended to have the greatest effect in those who were overweight at baseline and in those who weighed themselves regularly. Intervention women who rarely self-weighed gained weight (+0.07 kg) and regular self-weighers lost weight (-1.66 kg) a difference of -1.73 kg (95% CI; -3.35 to -0.11 p = 0.04). The intervention reported increased physical activity although the difference between groups did not reach significance. Both groups reported replacing high fat foods with low fat alternatives and self-efficacy deteriorated in the comparison group only.Conclusion: Both a single health education session and interactive behavioral intervention will result in a similar weight loss in the short term, although more participants in the interactive intervention lost or maintained weight. There were small non-significant changes to physical activity and changes to fat intake specifically replacing high fat foods with low fat alternatives such as fruit and vegetables. Self-monitoring appears to enhance weight loss when part of an intervention.Trial registration: ACTRN12608000110381

Introduction

Preventing weight gain is an important economic and public health response to the rapidly increasing rates of obesity. In Australia, almost 60% of the population are considered overweight or obese [1]. Treating established obesity is complex, requiring intensive education, counseling, multiple resources and ongoing support with limited efficacy [2].

To date, there are few reports of successful communitywide weight gain prevention interventions, and limited evidence from smaller targeted interventions. A systematic review in 2000, of interventions specifically to prevent weight gain revealed four published reports in adults based on two separate trials, but only one report of a successful outcome [3]. Subsequent reports on interventions to prevent weight gain produced conflicting results [4,5]. A more recent review reported interventions focusing on diet and physical activity to prevent weight gain found only 9 studies and of these, four positive studies [6]. Lower intensity, local, community-based interventions have the potential to support lifestyle change but need to be tested in diverse groups.

Women are an important target group as they are at high risk of ongoing weight gain. Longitudinal population studies report adult women are increasing weight at a mean rate of 600 g/year [7,8]. Small increases in body mass index (BMI) even within the normal weight range have been associated with increased risk of chronic disease such as diabetes [9]. Women with young children are at particular risk, yet studies rarely target this group. These women also make many of the daily food and activity decisions for families, influencing their children and partner's eating and physical activity levels [10]. Targeting women with children to prevent weight gain has the potential to achieve significant health benefits for themselves and their families.

Possible success factors for behavioral change include social support, goal setting and self monitoring. Self monitoring has been associated with improved maintenance after substantial weight loss in obese individuals [11] but has not been widely tested for the prevention of weight gain in healthy weight individuals. Self-efficacy is a possible predictor of behavior change and weight loss [12,13]. Interventions that enhance self-efficacy beliefs therefore have the potential to improve outcomes. Outcomes may also be enhanced through more effective delivery formats such as making programs tailored and interactive with frequent messages on diet and physical activity [14]. Interventions that are low intensity, low cost, address barriers to participation and achieve sustainable behavior change are urgently needed.

The primary objective of this study was to examine the short term effect of a longer term intervention, the Healthy Lifestyle Program (HeLP-her) which was specifically designed to prevent weight gain in women with young children living in the community. Here we report on the weight, weight related behaviors and self efficacy in participants following phase 1 of the intervention.

Methods

Participants

The target population were generally healthy, community-based mothers of at least one school-aged child (5-13 years) attending a primary school. Subjects were excluded if they were taking weight control medications, pregnant or became pregnant during the study, were breastfeeding infants under 6 months of age, or who wished to gain weight. To be inclusive of all community members, BMI was not used as an inclusion or exclusion criterion.

Recruiting

Twelve schools were recruited, paired with a school of equal size and within each pair, one school was randomly allocated to intervention (n = 6), the other to control (n = 6) using computer generated numbers. All mothers of children who attended these primary schools were invited by letter to participate and register interest by return mail, phone, email or fax. The study sampling and intervention were designed to target clusters of mothers associated with particular schools to reduce possible contamination between participants. The research teams randomized the schools and because they delivered the program were aware of the allocation of schools to intervention or control. Scoring and data entry was performed by team members blind to the allocation of participants.

Two hundred and fifty women were recruited progressively from April 2006 to August 2006. These women were given information packs containing an explanation of the study, questionnaires, completed a written consent and were randomized to intervention (n = 127) or control (n = 123) according to their school association.

Prior to attending group sessions, women were asked by survey to estimate their current weight. Participants were weighed and measured at the first group session and received a request for a fasting blood sample. Participants were given results of baseline measurements including blood tests after recruitment so as not to influence participation.

Intervention phase 1

The intervention content was based on the social cognitive theory, specifically, goal setting, self monitoring, social support, problem solving and relapse prevention training offering multiple avenues to behavior change [15]. In phase 1, participants attended four sessions; three one hour interactive group sessions in the first month, plus one review session at four months delivered by an experienced Dietitian. Content included evidence based messages with clear goals on diet, (e.g. eat 2 serves fruit and 5 serves vegetables each day), physical activity (e.g. aim for 8,000-10,000 steps per day) and behavior change (e.g. monitor yourself regularly). Written handouts were provided. In the following sessions outcome expectancies were discussed to clarify the intervention aim to prevent weight gain, not to promote weight loss. Regular daily or weekly self monitoring of weight was strongly encouraged. Women were encouraged to enter voluntary school based walking groups or to walk with friends for social support. A pedometer was provided as a voluntary self monitoring tool and women were given instructions to aim for at least 8,000-10 000 steps per day. A final visit at four months reinforced lifestyle and behavioral messages and collected data in the intervention group. All sessions were held in groups, ranging in number from 10-30 participants, at the local primary school. Ongoing support was provided through one contact per month via text messages, phone calls or email encouraging and reminding participants of the diet, physical activity and behavioral strategies discussed in the group sessions.

Comparison group

The comparison group attended a single thirty minute, non-interactive health education group lecture based on the Australian Dietary Guidelines and the Australian Physical Activity Guidelines. They received readily available pamphlets based on these Guidelines [16,17]. They received a pedometer to use as they wished over the year, but no daily step goal. They received no further support, but completed a brief mailed questionnaire at 4 months, and returned for final data collection at 12 months.

Study Measures

Anthropometric measures Self reported weight data was collected in both groups at baseline and at 4 months. Measured weight using a calibrated electronic scale (Tanita model BWB-800 digital scale) was collected in both groups at baseline and the intervention only at 4 months. We did not weigh the control group at 4 months to avoid any potential intervention effect of weighing, as the long term study is ongoing.

Physical Activity

The International Physical Activity Questionnaire short version (IPAQ) has been validated and was used to measure usual weekly physical activity [18,19]. Physical activity was expressed as a continuous variable; MET-minutes per week (MET-mins = MET level × minutes per day × days per week) where 1 MET is equivalent to resting energy expenditure and according to IPAQ categories, walking, moderate and vigorous

Diet

Fat intake was measured using the validated Fat Behavior Questionnaire (FBQ), a reliable and responsive measure of dietary fat intake [20]. The FBQ has been used in dietary studies and reported correlations with fat intake for fat related subscales using food diaries and food frequency questionnaires ranging from 0.60-0.77. FBQ is measured on a Likert scale; a mean score is generated overall, along with individual sub-factors. Low scores indicate low fat intake and high scores indicate high fat intake.

Self monitoring

To assess self monitoring we asked both groups at baseline, and again at 16 weeks how often they weighed themselves; daily, weekly, monthly, occasionally or never. Those who weighed daily or weekly were considered regular self weighers and those who weighed themselves monthly, occasionally or never, were categorized as nonregular self weighers.

Self efficacy

The Eating and Exercise Confidence Scale developed by Sallis was adapted to measure self efficacy [21]. The reported reliability for the domains of physical activity and eating are 0.68 and 0.43-0.68 respectively and internal consistency was 0.83-0.85 and 0.85-0.93 respectively. Wording in the eating scale was modified to match Australian foods. Questions related to salt intake were omitted as they were irrelevant to this intervention. An additional question was included, 'how confident are you that you can control your weight if you wished?' to measure self efficacy for controlling weight. Scoring was based on a likert scale, a mean of correctly completed questions generated for each domain.

Ethics approval for this study was obtained through the Southern Health Human Research Ethics Committee.

Statistical Methods

To account for the clustered design we used an intra-cluster correlation of 0.02 and an estimated cluster size of 30 to determine sample size. We calculated that 110 participants, 5-6 clusters, were therefore required for each group at 90% power to detect at least a 600 g difference in weight between intervention and controls, the mean annual weight gain in women.

Data were analyzed at the participant level. First sample means, standard deviations (SD), and proportions were calculated for relevant demographic characteristics of the population and differences assessed using chi 2 . The main outcome was a difference in weight change between groups at 16 weeks. Firstly, self reported weight was analyzed using linear regression, where individual differences in weight between baseline and week 16 were derived, the difference regressed on group assignment, adjusting for the clustering effect of school and thereby generating appropriate confidence intervals. Secondly, a difference in measured weight between baseline and week 16 in the intervention group only was calculated and analyzed using regression as described above. Within group changes from baseline to 16 weeks in all variables, were analyzed using t-tests. Differences between groups in all variables were measured using linear regression, after first generating a difference in the score from baseline, and adjusting for clustering as described above. Analysis was based on the women who returned for measurement and reported their weight via mailed survey. Intention-to treat analysis will be performed on the final data collected at 12 months.

Self monitoring was analyzed by dividing the participants into two categories, regular self-weighers (daily or weekly) and non-regular self-weighers (occasional or never). We used linear regression to estimate the association between regular self-weighing and weight change, using the difference in self reported weight from baseline to four months as the dependent variable and the self weighing categories as independent variables. All data were analyzed using Stata 9 (Statacorp, Texas, USA) statistical software program. Figure 1, shows the flow of participants through the study. Three hundred women responded to our invitation (11%) and 250 participants were recruited. Differences in demographic characteristics at baseline between intervention and comparison groups were small (Table 1). One hundred and seventy three returned the 4 month questionnaire.

Results

Weight Change

Using self-reported weight, both control and intervention groups reported a similar but non-significant mean weight loss at 16 weeks, -0.72 kg (95% CI:-1.59 to 0.14 p = 0.10) and -0.75 kg (95% CI:-1.57 to 0.07, p = 0.07) respectively. However, based on the measured weight, the intervention group participants significantly reduced weight by -0.78 kg (95% CI: -1.22 to -0.34, p < 0.001) (see additional file 1). There were differences between groups in the distribution of weight loss after stratification by BMI category, although this did not reach significance (figure 2). We then further stratified women into those who lost weight (≥ 1 kg), maintained weight within 1 kilogram of baseline (+/-0.9 kg) to account for day to day variation in weight, or gained weight (≥ 1 kg). More women in the intervention group lost or maintained weight compared to the comparison group, particularly if they were overweight at baseline ( figure 3). Again, the difference between groups did not reach significance. The obese category reported some large increases or decreases in weight over this short period (figure 3).

Weight monitoring

Intervention participants who regularly weighed themselves reported mean self-reported weight loss at four months (-1.66 kg), significantly different to those who did not weigh themselves (+ 0.07 kg), a difference of -1.73 kg, (95% CI: -3.35 to -0.11, P = 0.04). This was different to the control group where although regular self-weighing was associated with weight loss, the difference in reported weight change between the regular weighers and nonweighers was not significant (-1.41 kg (95% CI: -3.18 to 0.27, P = 0.1).

Diet and physical activity behaviors

The fat-behavior questionnaire measured 5 sub-factors of fat intake behavior where low scores are associated with low fat intake. The difference between intervention and control groups in dietary fat behavior at four months is reported (see additional file 1).

Both groups increased physical activity; the intervention reported greater increases, although the difference between groups did not reach significance (see additional file 1).

Self Efficacy

Self-efficacy (SE) beliefs were measured in three domains on a Likert scale as confidence to control weight, improve diet and participation in physical activity. There was a decrease in all three self-efficacy domains in the comparison group, with a significant decrease in both diet and physical activity domains. Self-efficacy in the physical activity domain decreased in the intervention group although no differences between groups were detected.

Discussion

Prevention of weight gain is an important step in reducing the impact of obesity on population health, yet there are few reports of successful interventions to date. Here we have reported on a low intensity intervention specifically to reverse the current trend of weight gain seen in Australian women.

Self-reported weight is commonly used in interventions due to the convenience and low cost. While it is considered to under report actual weight, it has been suggested self-report may accurately reflect changes in weight [22]. We did not weigh the control group at 4 months to avoid any unplanned intervention effect of weighing as the longer term study was still in progress. While we cannot be sure the self-reported weight changes described are not due to under-reporting, both groups were weighed at baseline and this may have contributed to more accurate self-reporting at 4 months.

It appears a similar small weight loss has occurred in both the comparison group and the intervention group. The weight change itself is of limited clinical importance because of the short term nature of the study, but it does point to interesting short term behavioral change in women with young children who are difficult to engage in health interventions. Previous reports including our own suggest the majority of women are dissatisfied with their weight even those within a healthy BMI range, and frequently use weight loss behaviors [23,24]. It is interesting then that even a single education session in the control group resulted in small weight loss in the short term. The program may have influenced early motivational changes in women as described in the Health Education Model, or influenced women at the contemplation and action stage as described in the Trans Theoretical Model. As participation was voluntary there is potential for a more motivated group to be recruited in both groups and this may partly explain the weight loss. However the women were invited to attend a lifestyle program, not a weight loss program and we anticipated we might recruit those who were already active, consuming a healthy diet and maintaining their weight. However the recruited participants included those who were overweight and obese as well as normal weight and the proportion who were inactive was similar to population levels as we have reported previously [25]. So whilst some women may have attended with the intention of Body mass index, measured as weight in kilograms divided by height in meters squared c Numbers may vary due to missing values or incorrectly completed surveys as participants were given a 'prefer not to answer' option for income. d n = 110 intervention and n = 106 controls correctly completed food frequency questionnaires e n = 89 intervention and n = 89 controls correctly completed IPAQ activity questionnaires losing weight, we do not believe the majority of women volunteered with this intention. If in fact we did recruit a sample that was already engaging in healthy lifestyle behaviors we would expect to see an attenuated effect among the respondents, and hence the effect size is an under-estimate of the effect which would be seen in all women. This suggests that being weighed and some simple general guidelines provided in a community setting may be sufficient to assist short term behavior change leading to better weight control in some women, at least in the short term. The greater weight loss reported in overweight and obese women suggests that even a single education session will encourage significant weight loss in some, but not all, overweight and obese women. Previous studies suggest this is not likely to be sustained long term. It is possible some women respond well to community interventions and it may be important to determine how these women can be identified to improve outcomes. Of concern is the large number of women who reported weight gain in each BMI category even in this short period.

The intervention group not only achieved weight loss, but there was a trend toward small, but potentially important changes to health related behaviors such as physical activity. Accurately measuring small changes to dietary intake and physical activity is difficult due to the lack of sensitive tools. We were unable to determine a difference between groups in fat intake behaviors in the short term. Both groups reported replacing high fat foods and snacks with lower fat alternatives such as fruit and vegetables, which potentially reduces the overall energy density of the diet and possibly contributed to the small energy deficit and weight loss. Some of the lower fat behaviors such as avoiding frying food and using low fat meats are well known messages throughout the community. Some women may 1 Flow chart of subject enrolment, random assignment and completion intervention delivery have already been practicing these behaviors resulting in little further change attributed to the intervention. However, the small improvements in physical activity and diet and the associated changes in energy balance are consistent with that expected to prevent population weight gain long term, estimated to be as little as 60 kJ per day [26]. The weight change reported here is important if sustained long term in populations [27]. The longer term results of this study will help determine the clinical importance and sustainability of the small energy deficit and weight change.

Self-weighing appears to facilitate weight loss when included as part of a behavior change intervention. There is only one report of using self-weighing in interventions specifically to prevent weight gain, although there are reports of the successful use of weight monitoring in obesity treatment and the subsequent prevention of weight regain [28]. Our results confirm those seen in the 'Pound of Prevention' a large community prevention intervention, where at least weekly weighing was associated with weight loss, although they did not show a difference between intervention and control. The study showed no detrimental effect of self weighing [14]. Simple methods of monitoring progress such as self-weighing may be a viable population recommendation although potential detrimental effects would need to be fully evaluated first.

Self-efficacy has been reported to be a predictor of successful behavior change. In this study, we were not able to show a correlation between self-efficacy and weight change despite positive correlations in other studies [29]. Self-efficacy declined over this short period, particularly in the control group. Intervention components such as outcome expectancy discussions, social reinforcement and modeling may have helped maintain self-efficacy in the intervention participants. The decline in self-efficacy for physical activity cannot be explained easily, although Bandura theorized that past successful experience is a powerful influence on self-efficacy and is supported by a study by Hofstetter [30]. Declining self-efficacy for physical activity in women with children has also been demonstrated previously [31]. This group may therefore need additional support to maintain self-efficacy for physical activity behaviors. Possibly, failure to employ the planned physical activity may have led to a decline in confidence to participate in future activity. This is explained partly through research on mediators of self-efficacy [32].

This study is important as it is the first to target mothers of young children specifically for the prevention of weight gain. This intervention recruited a representative sample of community dwelling women with children in Australia which along with other baseline characteristics has been reported previously [25]. Overall approximately 11% of Percentage of participants who lost, maintained or gained weight  invited participants responded. In the context of population reach the school setting gave access to all available women with children, unselected in terms of health risks. Reaching and changing the behavior in 11% of women with children translates into a substantial health promotion intervention

We were not able to show a significant difference between the groups in weight change and some specific lifestyle behaviors. The inability to detect these differences may reflect the inadequacy of the available self-report questionnaires to detect small changes. We cannot eliminate the possibility that self-reported improvements in diet and physical activity may also be the result of positive response bias. It is also possible seasonal variation contributed to the weight change although this was limited by having a rolling period of data collection. The study was powered to detect a 600 g difference between groups in the long term, and not adequately powered to detect the small difference observed here at four months. The intervention aimed for small consistent changes to lifestyle and this small energy deficit is difficult to measure with available tools. Despite this, the weight change and the behavior change seen in the intervention group is encouraging for the longer term success of this intervention.

Conclusion

Both, a low-intensity, interactive, lifestyle intervention as well as a single group health education session prevented weight gain and resulted in small weight loss in the short term in community based women with children. More intervention women reported weight loss or maintenance than in the comparison group. There were small changes to diet and physical activity behaviors in both groups, specifically replacing high fat foods with low fat alternatives such as fruit and vegetables. Regular monitoring of weight appeared to enhance weight loss associated with the intervention group. Further investigation will establish the sustainability and long term effectiveness of this intervention on the prevention of weight gain

Figure 1 1
1Flow chart of subject enrolment, random assignment and completion intervention delivery.

Figure 3
3Percentage of participants who lost, maintained or gained weight. (a) Control group BMI < 25 n = 24, BMI 25-29.9, n = 38, BMI ≥ 30 n = 20. (b) Intervention group BMI < 25 n = 37, BMI 25-29.9 n = 28, BMI ≥ 30 n = 21.

Table 1 :
1Baseline characteristics of the HeLP-her intervention by group assignmentVariable
Intervention group
(n = 127)

Control group
(n = 123)

P value a

Age at baseline, mean (SD), yr
40.6 (4.8)
40.3 (4.8)
0.62
Height Mean (SD), cm
163.1 (6.0)
162.9 (5.6)
0.78
Weight, kg
Weight Range, kg

73.2 (13.8)
46.3 to 115.6

74.6 (16.1)
44.6 to 129.6

0.45

BMI Mean,(SD) b kg/m 2
27.5 (5.1)
28.1(5.8)
0.40
Hip, cm
106.6 (11.0)
108.1(11.8)
0.29
No. of children, mean, (SD)
2.3 (0.7)
2.4 (0.8)
0.23
Waist circumference mean, (SD), cm
94.8 (12.6)
96.8 (14.6)
0.24
Energy intake (kJ/day) d
6648 (2204)
6830 (2361)
0.55
Energy expenditure Met-mins/week e
1504 (1657)
1653 (452)
0.52
Highest Education
Up to year 10 n (%)
25 (21.0)
36 (30.3)
Year 12
25 (21.0)
26 (21.9)
0.31
Trade or certificate
33 (27.7)
24 (20.2)
University or higher
36 (30.3)
33 (27.7)
Income ($ AUD) c
< 40,000
22 (18.8)
27 (22.8)
40-60,000
26 (22.2)
18 (15.2)
0.08
60-80,000
20 (17.0)
26 (22.0)
> 80,000
31 (26.4)
33 (27.9)
No answer
18 (15.3)
14 (11.8)
Employment (%)
Not working
46 (40.3)
49 (41.1)
Part time
61 (53.5)
63 (52.9)
0.99
Full time
7 (6.1)
7 (5.8)

Abbreviations, MET-mins/week = MET level × minutes per day × days per week, where 1 MET is equivalent to resting energy expenditure (MET
level, walking, 3.3, moderate 4.0 and vigorous 8.0)
a P values from 2-sample t tests for continuous variables or from chi2 tests for categorical variables
b
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Authors' contributionsCL HT DJ designed the study. CL DJ analysed the results. KB AD contributed to the psychological and behavioural aspects of the design and intervention components and contributed to the interpretation of results and drafts of this paper. CL was responsible for design, recruiting, delivering the intervention and arranging and supervising the collection of data, analysing the data and writing the manuscript. HT provided intellectual input into all aspects of the design, data collection, analysis and reporting. All authors read and approved the final manuscript.Competing interestsThe authors declare that they have no competing interests.at 4 months (mean difference, 95% CI).DescribesAdditional materialAdditional file 1Change from baseline to 4 months in weight related behaviors (mean, 95% CI) according treatment groups, and differences between groups
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Challenges facing the implementation of water demand management initiatives in Gauteng Province

R S Mckenzie
WRP (Pty) Ltd
PO Box 15220075Brooklyn SquareSouth Africa

W Wegelin
WRP (Pty) Ltd
PO Box 15220075Brooklyn SquareSouth Africa

Challenges facing the implementation of water demand management initiatives in Gauteng Province
18168E3B4EE48FC13B1C4A803430B4CC52B4WDMpractical implementationproblems in SA
Gauteng Province is the industrial heartland of South Africa and is one of the few large urbanised areas in the world that is not located adjacent to a major source of water.The demand for water in Gauteng outstripped the local resource of the Vaal River many years ago with the result that the area relies heavily on large water schemes which transfer water from adjacent river basins into the Vaal River basin.The water transfer schemes associated with the Vaal River basin are large by any international standards and the water resource system is one of the most complex and integrated anywhere in the world.As the demand for water continues to grow in Gauteng, the Department of Water Affairs and forestry is investigating the various alternative water resource development options as well as the potential for reducing the growth in demand through water conservation (WC) and water demand management (WDM) measures.From the most recent investigations it has become clear that WDM is no longer considered a possible option but rather a necessity that must be implemented as a matter of urgency.It has been established that even if new water resource development options are implemented, it will still be necessary to introduce the WDM measures.In this regard, several of the large municipalities in Gauteng have already commenced with various WDM interventions, some of which are already in operation and showing significant savings.The paper will highlight the need for WDM in Gauteng and provide details of the latest investigations into the potential savings that can be achieved.Some of the key problems that are hampering the implementation of WDM interventions in Gauteng will be discussed and the measures taken to overcome these difficulties will be explained.The benefits that can be obtained from a potent web-based data acquisition system which is already operational in several parts of Gauteng will also be highlighted.The paper concludes with the clear message that wasting water in Gauteng province is a luxury that cannot be sustained and measures to eliminate the wastage must be introduced as a priority before the situation deteriorates to such an extent that water shortages become a common occurrence.

Introduction

Total water losses from municipal water distribution systems are generally considered to be the sum of the apparent (often referred to as administrative) losses and the real (often referred to as physical) losses or leakage.The total losses from municipal reticulation systems for South Africa as a whole were recently (Seago and Mckenzie, 2007) estimated to be in the order of 1 150 x10 6 m 3 /a representing almost 30% of the system input of approximately 4 000 x10 6 m 3 /a. in 2005.It must be noted that these estimates are based on a sample of municipalities throughout South Africa which represented just under 70% of the water supplied to municipalities.It was not possible to examine all municipalities and the figures were therefore extrapolated to provide an estimate of the losses for the country as a whole.These preliminary estimates of water loss provide the first realistic estimate of water losses from municipalities throughout South Africa based on a pragmatic and realistic assessment of more than 300 individual water supply systems.

Using percentages to quantify water losses can be very misleading and is not recommended by the International Water Association, since the results are highly dependent on the consumption relative to the total water supplied.Percentages will always tend to suggest low losses in systems which have high unit consumption while the same volume of losses will show up as a high percentage value in systems where consumers use relatively little water.Having highlighted the potential problems with using percentages to quantify leakage and other losses from a water supply system, it is clear that many suppliers and government organisations will continue to use percentages both in South Africa and around the world.The estimated total water losses (30%) for the whole of South Africa is clearly a large portion of the water supplied to the municipalities but is not abnormally high.Although it is generally accepted that percentage losses should not be used for comparison purposes between systems, they are still widely used throughout the world water industry, as can be seen in Table 1.

Taking into account, the potential problems associated with percentages, the figures in Table 1 highlight the fact that percentages remain a commonly used indicator for measuring water losses throughout the world and that the South African leakage values are similar to those of many developed countries and much lower than those of most of the developing countries.This does not suggest that South Africa should be complacent about the current situation.

Many water audits have been undertaken throughout South Africa over the past 5 years, most of which were undertaken through projects supported by the South African Water Research Preliminary water audits were undertaken for the key demand centres in Gauteng and the surrounding areas which effectively involved developing water audits for 49 separate systems.This was one of the most comprehensive water audit assessments undertaken to date in South Africa and the results proved very useful and informative and are provided in the appropriate DWAF report (DWAF, 2006).The purpose of the study was to provide a realistic estimate of the potential savings that can be achieved through WDM interventions in the main urban areas of Gauteng.The assessment was based on a combination of the assessment of the overall water balance of an area together with practical knowledge of the area which in turn was supported by additional data from night-flow analyses and analyses of system pressures.

In order to carry out the assessment it was first necessary to agree on the terminology to be used.The notation used by the IWA for water balances has been recognised internationally as the most comprehensive and appropriate water balance worldwide and was adopted in this paper.The basic structure of the IWA water balance is shown in Fig. 1 (Seago and Mckenzie, 2007).

During the assessment of the potential savings from WC/ WDM for the Gauteng area, it was found that the standard IWA water balance lacked certain information required by the project team to estimate realistic savings.The problem is particularly significant in South Africa and is due in part to the 'free basic water allowance' and in part to the high levels of non-payment for 'Billed Authorised' water -i.e.water that is metered and billed to consumers but no payment will ever be recovered due to the unusually high internal plumbing leakage and excessive garden irrigation.In many other countries, such wastage would not be tolerated and the consumers would be cut-off or forced to pay the outstanding accounts.In South Africa, however, this is not the case in many areas and such wastage continues unabated.In order to address this issue, the 'revenue water' component in the standard water balance as shown in Figure 1 was modified to that shown in Fig. 2 (Seago and Mckenzie, 2007) where it has been split into 3 components which have specific relevance in the South African situation.

The modification was effectively achieved by splitting the 'revenue water' component into 3 components namely:  • Free basic water -can be considered as billed and paid for at a zero tariff • Recovered revenue water which is billed and paid for by consumers • Non-recovered water which is reflected in the billing records as billed although there is no possibility of payment.

This last component is the key problem in many parts of South Africa and is very significant in some areas.For example, in a typical low income area with very high leakage where water is metered and bills are sent out in accordance with the metered consumption, the monthly consumption per property may be in the order of 50 kℓ.Of this 50 kℓ, the consumer receives 6 kℓ as the free basic allowance and a bill for the remaining 44 kℓ.Since it is a low income area, the residents are often unable to pay for the services and the accounts simply accumulate.Eventually, the water service provider decides to address the problem and installs either some form of restrictor or a pre-paid meter.If this intervention is implemented properly, the household leaks will usually be repaired as part of the process and the accumulated account will be written off as a 'once-off' gesture of goodwill by the water provider on the basis that the consumer agrees to pay for all water used from that date forward.Following the implementation of the cost recovery measures, the average consumption rarely remains at the pre-implementation levels and in most documented case studies the consumption drops significantly to approximately 12 kℓ/month (City of Johannesburg and City of Sao Paulo -personal communication).In effect, the interventions will result in a real reduction of approximately 38 kℓ/month per property.

The modification to the water balance is fully described by Seago and Mckenzie (2007) and has not been sanctioned by the IWA although it has been presented at several international conferences (e.g.Mckenzie, 2008 a;b and Mckenzie et al., 2007) and has survived any criticism to date.

This approach is required in many parts of South Africa to derive realistic estimates of what can be achieved through the implementation of various WDM interventions.If it is assumed that all water billed is in fact paid for and the demand therefore remains at the pre-intervention levels, there will be a serious discrepancy since the assumed increase in revenue water will not materialise.This can in turn alter the financial viability of the proposed interventions.It is therefore important to examine the payment levels carefully to ensure that the predicted savings and/or reductions in overall demand are realistic.It should be noted that the potential savings were assessed individually for each of the 49 areas mentioned previously and then added where appropriate to provide an indication of total potential savings per municipality.

The potential savings per municipality for one of the numerous scenarios analysed are shown in Table 2 (DWAF, 2007) from which it can be seen that the bulk of the savings are concentrated in the 4 main urban centres of Johannesburg, Ekurhuleni, Tshwane and Emfuleni.It should be noted that Emfuleni is the area where savings of almost 10 x 10 6 m 3 /a have already been achieved through the implementation of a large pressure management project (Mckenzie et al., 2007).From Table 2 it can be seen that approximately one third of all water supplied to the areas is considered as non-revenue water.This is a combination of physical leakage and administrative losses which tend to vary from area to area.Based on the analyses of the 49 areas, it was estimated that approximately 161 x 10 6 m 3 /yr can be recovered or saved through the implementation of the various WDM interventions.

Cost of implementing WDM interventions

When considering the implementation of WDM interventions, the normal approach is to assess the unit reference value (URV) of the savings achieved and compare this to the unit reference value of the next major augmentation scheme.While it is possible to develop a realistic unit reference value for the water produced from the next major augmentation scheme, it is more difficult to develop such a number for the WDM interventions.

When such values are provided, they are normally criticised by either the water resource managers or the water use efficiency managers and in most cases both have some valid reasons for the criticism.For example in the case of the Vaal River System Analysis, considerable effort was spent trying to establish the costs associated with the implementation of the various WDM interventions in each of the 49 areas considered.In each area a range of WDM interventions were included and the capital expenditure (CAPEX) and operational expenditure (OPEX) associated with each were estimated based on the practical experience of the project team.Several different scenarios were considered and the costs and related savings from a typical scenario are provided in Table 3 (next page).

The values provided in Table 3 should not be taken out of context and are provided as indicative of what would be required in the scenario above in order to implement the full range of WDM interventions that would yield the savings provided previously in Table 2.While the actual figures have yet to be assessed in more detail, they provide an estimate of the level of funding that would be required in order to implement WDM initiatives throughout Gauteng.The costs are clearly significant and largescale implementation of WDM initiatives should not be considered as a trivial investment.While considerable debate continues regarding how such costs should be calculated, it is clear that WDM interventions will require budgets of a similar magnitude to the capital-intensive water transfer schemes.

When considering the figures provided in it should be noted that the operational and maintenance costs are similar in magnitude if not higher than the capital costs of implementing the WDM interventions.This is an important and often overlooked aspect of many WDM interventions where the savings tend to be very significant after completion of the projects.If the projects are not properly maintained, however, they tend to collapse and any savings achieved initially are soon lost.This has been one of the key problems throughout South Africa which has led to the relatively poor perception surrounding WDM projects countrywide.There are many examples of failure where potentially successful WDM projects have collapsed completely due to the lack of maintenance.This is unfortunately one of the key problem issues associated with WDM in the South African context.Another problem experienced when trying to provide the likely costs of WDM interventions to the water resource planners concerns the inclusion or exclusion of the maintenance backlog costs that should in theory be excluded from the calculations.In most areas with high leakage/losses, there tends to be a serious maintenance backlog in the water reticulation network which must be addressed before any new WDM interventions can be implemented.Such maintenance should be undertaken as normal practice by the municipalities, but this is often not the case.Before the proposed WDM interventions can be considered, significant expenditure will be necessary just to bring the system up to a normal level of operation.Such costs were included in the preceding example although they are not part of the subsequent WDM interventions.Such issues tend to complicate what is already a very complex issue and make it difficult to provide costs of the WDM interventions that are comparable to resource augmentation schemes.

With regard to the cost of possible WDM interventions in the Vaal River system, the costs associated with saving water through the WDM interventions are similar in magnitude to the costs associated with providing water from a new inter-basin transfer scheme.This is a bold and controversial statement which is based on certain assumptions regarding the maintenance costs and the manner in which the various unit reference values are calculated.Even if the maintenance costs (which should in theory be carried by the municipalities as a matter of their normal business) are excluded from the calculations, the average costs associated with the WDM interventions are high and remain in the same order as those of the most economical augmentation scheme.

One key difference between WDM interventions and aug-mentation schemes is that not all WDM interventions have the same payback ratio and in many cases, the payback for certain interventions can be as low as a month or two while for others it may be a matter of many years.In this regard it is often possible to select the most cost-effective WDM interventions to be undertaken first after which the less favourable options can be considered according to the available budgets.

Water resources situation in Gauteng

South Africa is fortunate to have a progressive water resource planning department within DWAF and the country has developed one of the most complex water resource networks in the world.Some of the major water transfer schemes associated with the Vaal River system are shown in Figure 3.The Vaal River system is widely recognised as the most important river basin in Southern Africa as it supports the bulk of the industrial water demands in Gauteng and the adjacent provinces.The complex network of dams and inter-basin transfer schemes is managed by DWAF using software developed over a period of almost 25 years to suit the local situation.The South African software can compete with any international software and can handle many additional aspects which are rarely included in other packages.

The success of the South African water resource management expertise is evident from the fact that the system has been providing a safe and reliable supply to all residents and businesses in Gauteng for the past 25 years with very few interruptions or shortages.This is a very impressive record in a semiarid country that must handle severe drought periods which can be in excess of 10 years in duration.

In order to provide sufficient water for the future, it is essential to undertake proper planning and appropriate development in time to support the ever growing demands for water.Such development will involve a combination of both WDM as well as supply side management.In the case of the Vaal River system, considerable work has been undertaken through DWAF to assess the growing demands and to ensure that sufficient resources are available to support them.In this regard, DWAF commissioned a new study to assess the demand and supply situation in the Vaal River basin and the preliminary results have been released through a series of open public meetings.While the results of the study are still being refined and adjusted, the key finding highlights the need for both WDM interventions as well as the construction of a new inter-basin transfer scheme.WDM is no longer considered to be one of several options but is now an essential component of the overall water resource planning process.

Figure 4 provides the results from a typical water resource assessment in which a new dam and transfer scheme are considered.It should be noted that this is one of approximately 20  One of the possible water resource development scenarios (DWAF, 2007) possible scenarios that were investigated as part of a separate project and the figure is presented to demonstrate the planning process.

In Figure 4 it can be seen that the current yield available from the Vaal River system is in the order of 2 900 x10 6 m 3 /a as indicated by the horizontal black line.This yield is currently provided by the Vaal River system which includes over 30 major dams and associated transfers.The largest reservoirs in the system are the Vaal Dam, Sterkfontein Dam, Katse Dam, Grootdraai Dam, Bloemhof Dam, and Mohale Dam.Between them, they have a combined storage capacity in the order of 9 000 x 10 6 m 3 or approximately 3 years' water supply.

The demand curve represents the projected water demand in the Vaal River system which in this case includes the potential savings from WDM.As can be seen, there is already a slight deficit between the supply and demand although it is unlikely to cause any problems and is already being addressed as indicated by the sharp drop in demand expected to occur between 2009 and 2011.

The 3 rd line which starts in the year 2018 represents the total system yield that will be available should this particular water resource transfer scheme be implemented.Clearly it will be sufficient to provide for future growth for many years to come.In the case of this particular demand scenario, the new scheme will be required by the year 2018 and this target date will change according to the actual growth in water demands.In other words, the success or failure of the WDM measures will have a major impact on the timing of the next augmentation scheme.This is a very important issue since any new water transfer scheme will take many years to plan and construct particularly in view of the environmental and legislative requirements that must be addressed.

The analyses undertaken by DWAF were based on numerous possible demand scenarios and were matched up against several possible water transfer schemes.Figure 4 represents the results from one specific demand scenario and one specific water resource transfer scheme.The Polihali transfer scheme shown in the figure was recently (December 2008) selected by DWAF as the preferred next augmentation scheme and it will be constructed and commissioned in Lesotho in due course.

Problems experienced when implementing WDM measures

While it is generally accepted that WDM is essential and in many cases the most cost-effective solution to addressing water shortfalls, it is often regarded as unpopular by the water resource planners.The key reason for the negative perception surrounding WDM, is due to its poor track record and the fact that in numerous case studies, the projected savings through a range of WDM interventions have either not been achieved or have proved to be unsustainable.The managers responsible for providing a reliable supply of water are therefore reluctant to delay future augmentation schemes on the basis of predicted savings that may not be achieved.Unfortunately, WDM's poor track record in South Africa is a fact that cannot be ignored and in many cases the predicted savings are not achieved.Little if any research or papers are delivered on such projects and valuable lessons which should not be repeated are often ignored.The key problems hindering the successful implementation of WDM include the following:

• Poor maintenance of the reticulation system -both prior and following the implementation of WDM interventions • Lack of support at the political level in the municipalities • Lack of consumer support.

Poor maintenance

Poor maintenance is a massive problem throughout many parts of South Africa and especially the previously disadvantaged areas where maintenance of water supply infrastructure has been neglected for many years in some cases.In cases where the water supply infrastructure has not been maintained properly, it is often virtually impossible to implement effective WDM interventions before the maintenance backlog has been addressed.It is an unfortunate fact, that the areas which have experienced a lack of proper maintenance are often the areas most in need of effective WDM measures and are the areas where the greatest savings could theoretically be achieved.It is often found that large scale infrastructure refurbishment or replacement is necessary in order to bring the system up to a reasonable level of service.Defining the appropriate level of service in South Africa is outside the scope of this paper.Only after the system is operating properly, however, can proper water demand management interventions be successfully introduced.

Lack of political support

Lack of political support is hampering the successful implementation of WDM interventions in many areas and is a major cause for failure of interventions which could arguably have been successful in a different political environment.In many cases it is found that the politicians, particularly at the municipal level do not support WDM interventions despite the growing pressure being placed upon them by DWAF.Without proper support from the local politicians, it could prove difficult to implement many of the obvious and highly effective WDM measures.A classic example is the lack of support for implementing and enforcing any form of garden watering restrictions in many areas.There are numerous municipalities throughout South Africa that experience intermittent supply in certain parts of their distribution system due specifically to garden watering.This problem occurs each year in many parts of Gauteng particularly towards the end of August and September when the temperatures heat up and before the first summer rains occur.Many systems fail to supply the sudden increase in demand and certain residents in the higher lying areas experience severe water shortages.

The solution to the problem is simple and can be achieved with the necessary political support, however, it is rarely considered acceptable to restrict garden watering and as a result the residents must endure a poor level of service.The significance of garden watering has been reported before (Jacobs, 2007;Jacobs and Haarhoff, 2007), with a water saving in some residential user categories exceeding 40% in the case of Cape Town (Jacobs et al., 2007) when outdoor use was curtailed during a period of water restrictions.

Lack of consumer support

Another key problem experienced in South Africa is the lack of consumer support.This is highlighted by the fact that the per capita water consumption in many areas is significantly higher than in many other countries which have greater natural water resources than South Africa.For example the average per-capita consumption in Sebokeng and Evaton is estimated to be more than 200 ℓ/cap•d.This can be compared to Brisbane in Australia where a figure of 130 ℓ/cap•d has been achieved.A major shift in the habits of all South Africans will be required in future to protect the existing water resources and to ensure that systems are not allowed to degenerate into those experienced by many other developing countries.Some progress is being made to educate consumers and to change their perceptions and habits with regard to water use.It is, however, a slow process and more effort will be required if significant progress is to be made.

Summary and conclusions

Water losses from municipal reticulation systems for South Africa as a whole were recently (Seago and Mckenzie, 2007) estimated to be in the order of 1 150 x10 6 m 3 /a representing almost 30% of the total system input of approximately 4 000 x10 6 m 3 /a in 2005.This water is lost through a combination of physical leakage (e.g.burst pipes) and commercial losses (e.g.admin errors, meter errors, etc.).The breakdown between the physical and commercial losses is not known and will differ from area to area.Although these losses are high, they are similar in magnitude to the losses experienced in many developed countries and well below the losses experienced in much of the developing world.

DWAF in association with the WRC are undertaking several studies to investigate the losses experienced throughout South Africa.One of the most intensive studies is being undertaken in the Vaal River system which supplies water to Gauteng and several of the adjacent provinces.The current reconciliation assessment of the Vaal River system represents the first study of its type in which an assessment of both WDM interventions and new augmentation schemes have been undertaken in such detail.

The potential savings and costs associated with the WDM interventions were assessed in a detailed and pragmatic manner in which both capital costs as well as operational costs were included.This paper reports on the preliminary findings and it is already clear that the costs associated with the WDM interventions are much higher than previously anticipated for various reasons and are likely to be in a similar magnitude to the resource augmentation options.It should be noted, however, that some of the specific WDM interventions will be more cost effective than others.It is likely that the more cost effective WDM options will be implemented first in which case the costs can be significantly lower than the corresponding costs of water delivered from the next augmentation option.

One of the key problems experienced with the actual implementation of new WDM measures is the fact that many water reticulation systems are currently not functioning properly due to many years or even decades of poor maintenance.In such systems it is often not possible to successfully commission new WDM interventions until the underlying problems have been addressed.Such maintenance should technically not be included in the cost of the new WDM interventions but unfortunately it is often necessary to take one step back before any forward progress can be achieved.The worrying aspect of the assessment is the fact that WDM is no longer one of the several options being considered in the Vaal River System but an essential component of the future planning process.In this regard it will therefore be necessary to address the maintenance backlog issue as a pre-requisite to the WDM interventions.

Another key aspect that has been identified in the assessment is the necessity of including a maintenance budget for any new WDM interventions.Such maintenance may well exceed the original capital costs of the WDM interventions but is an essential component of any new WDM project.

From the practical experience of the authors, it is clear that there is currently insufficient political will in many municipalities to address water wastage in the key problem areas.The key problem areas are considered to be those areas where water is not being paid for based on metered consumption.In such areas where sufficient water is available, it is the experience of the authors that the average household use tends to vary from an average of 30 kℓ/month to over 60 kℓ/month.Based on the evidence gathered through numerous site inspections, much of this 'consumption' is due to a combination of internal plumbing leakage and over-irrigation of lawns outside the houses.In the one or two cases where the municipality has managed to address the problem through some form of proper billing, metering and enforcement, the monthly demand drops to approximately 12 m 3 /month (City of Johannesburg, personnel communication).

The above water use figures clearly demonstrate a serious problem that exists in many parts of South Africa.What is not generally publicised and has not been researched, is the fact that the gross wastage often results in water shortages in some parts of a large reticulation system where residents experience intermittent supply.Such intermittent supply causes damage to the reticulation system and represents a direct health hazard to

Available on website http://www.wrc.org.zaISSN 0378-4738 = Water SA Vol.35 No. 2 (Special WISA 2008 edition) 2009 ISSN 1816-7950 = Water SA (on-line) 169 Commission (WRC) or through the Department of Water Affairs and Forestry (DWAF).The most recent work on this issue is a project on The Assessment of Non-Revenue Water and Leakage in the Vaal River System which was undertaken through a joint initiative supported by both DWAF and the WRC.

Figure 1
1
Figure 1Standard IWA water balance

Figure 2
2
Figure 2Modified IWA water balance for South Africa

Figure 3
3
Figure 3Major water transfer schemes in the Vaal River system(DWAF, 2007)

TABLE 1 Some typical water loss figures from around the world Country Details Total losses unless otherwise stated (%) Reference
AfghanistanKabul60%WDM Bulletin, Issue 58 (2003), p7AustraliaNew South Wales30%WDM Bulletin, Issue 81 (2007), p7AustraliaCountry9.5% (real losses)WDM Bulletin, Issue 52 (2002), p4CanadaMontreal40%WDM Bulletin, Issue 81 (2007), p7EnglandLondon42%SA Water Bulletin, November 1983, p3England and WalesCountries22%WDM Bulletin, Issue 58 (2003), p7England and WalesCountries16% (real losses)WDM Bulletin, Issue 52 (2002), p4FijiCountry55%Water 21, February 2004, p8FranceMarseilles36%SA Water Bulletin, November 1983, p4FranceCountry17%WDM Bulletin, Issue 23, June 1997, p 4GermanyMunich14%SA Water Bulletin, November 1983, p4GhanaCountryMore than 50%Water 21, June 2004, p10, Peter ReinaIrelandCountry50%WDM Bulletin, Issue 67, p3ItalyRome25%SA Water Bulletin, November 1983, p4JapanTokyo5.4%Water 21, June 2004, p25.KenyaCountry50%Water for Africa Cities, Issue 3, July 2000, p 3,MaltaGozo26% (real losses)WDM Bulletin, Issue 52 (2002), p4NetherlandsCountry5%WDM Bulletin, Issue 48 (2001), p6Nordic CitiesVarious2.5% (real losses)WDM Bulletin, Issue 52 (2002), p4Saudi ArabiaCountry30%WDM Bulletin, Issue 81 (2007), p7ScotlandCountry47%WDM Bulletin, Issue 68, p 8SenegalDakar30%Water for African Cities, Issue 2, April 2000, p7SingaporeCountry1% (real losses)WDM Bulletin, Issue 52 (2002), p4SpainCountry28%WDM Bulletin , Issue 35, June 1999, p 4

TABLE 2 Potential savings through WDM in Gauteng Area Annual demand (x10 6 m 3 /a) Estimated NRW (x10 6 m 3 /a) Possible savings (x10 6 m 3 /a)
2Johannesburg47015485Ekurhuleni2919128Tshwane2556616Emfuleni794921Rustenburg2683Mogale2462Govan Mbeki1851Matjhabeng1694Randfontein72<1Total1 186390161

TABLE 3 Example of costs for WDM Interventions (discounted to 2005)
3YearCAPEXOPEXTotalSavings(R million/a)(R million/a)(R million/a(R million/a)2004-05489500989712009-104115009105092014-152375007365532019-202375007365812024-25237500736614Total4 0676 50010 5685 661

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