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Chapter 4 Sustainability Assessment For Urban Water Management System 98
CHAPTER: 4
SUSTAINABILITY ASSESSMENT FOR URBAN WATER
MANAGEMENT SYSTEM
4.1 INTRODUCTION
Sustainability assessment is the first logical step before any sustainability-enhancement
planning. In short it is a type of approach like “does boiling water really need additional
heating?” Sustainability assessment means each case should undergo a preliminary analysis
to know its sustainability status before embarking on to more complex levels of data-
gathering, analysis and problem-solving stages for any planning practice.
Urban Municipalities are facing numerous challenges in respect of the provision and
management of water services. Various benchmarking initiative measures the performance of
authorities with respect to national standards and regulatory frameworks pertaining to the
delivery and quality of water services. These may become useful tool for municipality for
development of best practices and to determining potential for water services to be
sustainable in the long run for future perspective. Sustainability assessment is the process to
consider and measure the well being of people and the ecosystem together with the collected
data. It can be used to ranking fields of activity, giving improvement suggestion for
technology adoption, identifying the appropriate solutions for the proposed planning design.
(Li Shuping et al, 2006)
Integrated sustainability assessment is part of a new paradigm for urban water decision
making. Multi criteria decision aid (MCDA) is an integrative framework used in urban water
sustainability assessment, which has a particular focus on utilizing stakeholder‟s participation
(E.Lai et al, 2008). The United Nations Environment Program (UNEP) s (Millennium
Ecosystem Assessment, 2003) program has stressed the importance of better decision-
making for long term sustainability and the importance of utilizing sound scientific
knowledge Viz. Better information cannot guarantee improved decisions but it is a
prerequisite for sound decision making”. Decision making thus requires sound sustainability
assessment to provide key and timely information.
In this research work, for sustainability assessment methodology adopted is described further
in detail.
Chapter 4 Sustainability Assessment For Urban Water Management System 99
4.2 METHODOLOGY
Chart 4.1 Flow chart describing methodology for sustainability assessment
4.2.1 DEVELOPMENT OF SYSTEM BOUNDARY:
The system boundaries must be defined to include whole system rather than system
components. Moreover, the sustainability indicators (SI) must reflect all dimensions of
sustainability including all functional, economic, environmental and social- cultural aspects
(Balkema et al, 2002). The system boundary is defined as building a theoretical framework,
which provides the underlying basis for indicator selection and supported the overall index
structure. The four-dimensional view on sustainability was employed and these four
dimensions constituted the basic components of the sustainability assessment.
In other words, for sustainability assessment of urban water management system which
component of water system should be included? In this research, I have tried to incorporate
Aggregate weight of criteria and sub criteria
Composite index value (SI)
Decide system boundary
Decide criteria and sub criteria
Prepare questionnaire for interview of experts, stake holders
Ranking of criteria and sub criteria
Decide weightage of each criteria and sub criteria
Normalization of data
Data collection
Chapter 4 Sustainability Assessment For Urban Water Management System 100
different component related to water supply, waste water, storm water, rain water
recharging/harvesting and its sub criteria. The system boundary is decided based on
following approach.
Fig 4.1 System boundary for sustainability assessment
Literature review
By considering local issues related to water management
By considering component of life cycle of water supply
Waste water treatment Sludge treatment Land fill
Energy recovery
Rain water Rain water recharging /
Harvesting
Raw water
Water treatment
Distribution
Use
Waste water
generation
Energy
consumption
Storm water
collection
Chapter 4 Sustainability Assessment For Urban Water Management System 101
The literature related to sustainability assessment were studied and explained in previous chapter.
The local issues related to water supply as well as waste water management system were studied
and explained in chapter 1 (problem definition). The life cycle boundaries define the unit processes
to be included in the system. The life cycle for the urban water system starts with withdrawal of raw
water form source. It also includes components related to water and wastewater treatment. The life
cycle ends with discharge of treated sewage and disposal of sewage sludge either to land fill or
agricultural land. The system boundary covers storm water piped network and rain water
recharging/harvesting system coverage in the city. It also covers salinity ingress in Surat city. The
ground water is very important criteria but the data related to ground water table were not available
hence it was decided to skip otherwise it may result into false analysis.
4.2.2 SELECTION OF CRITERIA & SUB CRITERIA:
The system boundary was decided for the development of sustainability criteria and sub
criteria. This system model was adapted from the Triple bottom line approach used by
(christen et al, 2006). The criteria and sub criteria were decided based on prolonged time
perspectives to achieve more sustainable UWM system. The criteria selection (termed „data
selection‟) involved the selection of appropriate criteria for the field of research. It gives their
relevance to current issues, their appropriateness to the area in question, their scientific and
analytical basis plus their ability to effectively represent the issues designed for measurement.
The selected criteria represents following objectives to achieve sustainable water
management. This stage involves specifying a comprehensive set of objectives that reflects
all concerns relevant to the decision problem and measures for achieving those objectives
which are defined to achieve. Sub criteria measuring the same or similar aspects were either
excluded or replaced with more suitable indicator measures. Following guidelines were given
by (C Mureverwi et al, 2007) which is followed before deciding criteria and sub criteria.
Availability of data: The indicator should use good quality, affordable and readily available
data.
Simplicity: The information gathered for the indicator must be presented in an easily
understandable and appealing way. Complex issues and calculations should yield clearly
presentable and understandable information.
Chapter 4 Sustainability Assessment For Urban Water Management System 102
Policy relevance: The indicator should be associated with one or several issues around which
key policies are formulated. This is because sustainability indicators are intended for
audiences to improve the outcome of decision-making on levels ranging from individuals to
the entire biosphere. Unless the indicator can be linked to critical decisions and policies, it is
unlikely to motivate action.
Validity: The data used in the index should be collected using scientifically defensible
measurement techniques. Methodological rigor is needed to make the data credible for both
experts and the general public.
Time-series data: The indicator should use data which reflect trends over time.
Reliability: The same information should be provided by multiple applications of an
indicator using the same data. Ideally two different researchers should arrive at the same
conclusions using the same indicator.
The following table 4.1 represents main criteria chosen and its objectives for sustainability
assessment of the study area. The detail significance of measurement of each sub criteria are
mentioned in table 4.2 on next page.
Criteria Objective
Social social fairness and equitable resource distribution
Economic economically sound principles, economic growth and cost returns
Environmental use of renewable energy source, environmental protection and
preservation of ecological systems
Engineering sensitivity and robustness in the system
Table 4.1 Objective of different criteria for sustainability assessment
4.2.3 DATA COLLECTION
In the research work, data were collected based on decided criteria and sub criteria. This
includes data related to social, economic, environmental and engineering factors and its sub
criteria like population served by water supply and waste water system, storm water, capital
investment, economic expenditure and maintenance, water supply per capita per day, waste
water generation per capita per day, area covered under pipe network, energy consumption,
Chapter 4 Sustainability Assessment For Urban Water Management System 103
Criteria Sub criteria Significance of measurement
Social Access to water supply % population covered under water supply
Access to sanitation % population covered under water supply
Water
availability/capita/day
Per capita water supplied on daily basis
Supply hours Water supply hours on daily basis at
consumer tap
Service complaints Complaints related to water supply
Flood prone area Area which become water logged during
rain fall
Capital investment
Total initial investment towards water
supply infrastructure
Economic Cost recovery & Operation
and maintenance cost
Routine daily expenditure for water supply
and maintenance cost
Research and development
investment
Fund kept aside for research and
development
Water withdrawal
Quantity of water withdrawn from raw water
source on daily basis
Waste water treatment
performance
Verification for treatment and disposal
standard of waste water
Pollution load on
environment
How much pollution can be generated due to
disposal
Water reuse Treated waste water is being used or not
Recycling of nutrients and
sludge reuse
Nutrient and sludge is being used or not
Environmental Storm water-area covered
under pipe network
% area covered with piped network
Rain water
harvesting/recharging
% area covered with rain water
recharging/harvesting system
Salinity ingress Area in which ground water become saline
Engineering Metered connection Area cover under metered connection
Service interruption &
Water losses
Water loss in piped network and water
supply infrastructure
Table 4.2 significance of different criteria measurement for sustainability assessment
cost recovery, revenue collection from water supply, sewerage system, flood prone area etc.
from Surat municipal corporation (SMC).
In the first phase, for sustainability assessment most of the data were easily available from
Surat municipal offices and www.suratmunicipal.org website. One of the important data
(depletion of ground water table) was not available. How to address the issue when data were
missing is very challenging job. The non-availability of data is one of the largest constraints
to the success of most assessment study; the instance with incomplete data either substitution
Chapter 4 Sustainability Assessment For Urban Water Management System 104
or exclusion of that data were adopted hence sub criteria depletion of ground water table was
omitted in this research work.
4.2.4. FIELD SURVEY
The questionnaire was prepared based on criteria and sub criteria which are essential for
sustainable urban water management. The survey was conducted among different category of
people to get representative results. The people involved in survey were local residents of the
Surat city, experts in the field of water management and stake holders.
The field survey consists of filling of two types of questionnaire:
Ranking sheet
Rating sheet
The ranking sheet defines the priority of different factors in comparison with rest of the
factors. The criterion weight can be defined as a value assigned to an evaluation criterion
which indicates its importance relative to other criteria under consideration. Assigning
weights of importance to evaluation criteria accounts for
1. The changes in the range of variation for each evaluation criterion, and
2. The different degrees of importance being attached to these ranges of variation.
For local residents of the city only ranking sheet was used as they can easily understand the
criteria and rank them as per their priority of importance. The weightage assignment is very
important and prime survey in the field study. The weight assigned by the experts on different
aspect of water management based on priority was the major input gathered through survey
and discussion with experts. Their vast experience and expertise increased value added
opinions in the priority-based field study. The co-operation was fully devoted by the experts.
Some have asked for soft copies of survey sheet in that case soft copy were sent them so time
for the second visit was saved. The survey mainly comprised of forty personal interviews
with local public, experts and stakeholders. The questionnaire format is shown below. The
summaries of questionnaire sheet (ranking and rating) are attached in annexure. The
questionnaire is enclosed as appendix I. The ranking sheet and rating sheet along with final
weightage is attached as appendix II and III respectively.
Chapter 4 Sustainability Assessment For Urban Water Management System 105
4.2.5. ANALYSIS METHOD:
In recent years, quantitative multi criteria methods have been widely used for comparative
evaluation of complicated technological and social-economic processes as well as for
determining the best alternative among the available options and ranking the alternatives
based on their significance for a particular purpose. Professor of Vilnius Gediminas
Technical University E.K. Zavadskas was the first to use these methods in Lithuania in the
mid eighties of the last century for evaluation, substantiation and choosing of optimal
technological solutions at various stages of construction. In this period, new multi-criteria
evaluation methods were developed and widely used in the world in various scientific and
practical areas. Later, numerous disciples and colleagues of Prof. Zavadskas as well
representatives of various scientific schools extensively used the considered methods in
Lithuania.
The main concept behind the quantitative evaluation methods is integration of the values of
the criteria describing a particular process and their weights (significances) into a single
magnitude i.e. the criterion of the method. For some particular (maximizing) criteria, the
largest value is the best while for others (minimizing criteria) the smallest value is the best.
The units of criteria measurement are also different. The alternatives compared are ranked
according to the calculated values of the criterion of the method. Great numbers of multi-
criteria evaluation methods based on different logical principles and having different
complexity levels and the inherent features have been created in the world. There is hardly
any „best‟ multi-criteria evaluation method. Therefore, a parallel use of several multi-criteria
evaluation methods as well as the analysis of the spread of estimates and averaging of the
values obtained may be recommended for evaluating complicated multifaceted objects and
processes ( Valentinas Podvezko et al, 2011). A simple form of MAUT or simple multi-
attribute rating technique (SMART) which uses simple additive weighting method as the
utility function (Mingshen Wang, 1998) is used in his research.
The method SAW (Simple Additive Weighting) is one of the simplest, natural and most
widely used multi-criteria evaluation methods. It clearly demonstrates the idea of integrating
the values and weights of criteria into a single estimating value – the index of the method. In
this work, the Simple additive weightage method is used and following steps were adopted
for index calculation;
Chapter 4 Sustainability Assessment For Urban Water Management System 106
A ranking approach was adopted, in which criteria and sub-criteria were ranked
within their category.
In second step, expert weights were assigned to all criteria and sub criteria for rating.
The criteria chosen were both qualitative and quantitative over widely differing on
ranges. The data were normalized. The normalization involved the conversion of
these criteria and sub criteria to a comparable form which ensures commensurability
of data. The criteria were compared with target value (service level benchmark) based
on their unit of measurement.
The scores were normalized (converted) by the following formulas
Xij= 𝒂𝒊𝒋
𝒂𝒋𝒎𝒂𝒙
---------------- (1)
Xij=𝒂𝒋 𝒎𝒊𝒏
𝒂𝒊𝒋
---------------- (2)
Where, aij = actual existing data value for the sub-criteria
ajmax, ajmin = target data value for sub-criteria
When criteria were maximized, formula (1) is to be used, and formula (2) is to be used when
criteria were minimized. For normalization threshold value/service level benchmark is taken
as a standard value.
The Weighting entailed the aggregation of criteria and sub-criteria.The aggregation
refers to grouping of criteria and sub-criteria. A composite index approach was
employed to calculate the overall sustainability index score. The normalized value for
each criterion Xij, was multiplied by the aggregate weight of criteria and sub-criteria.
The score for each sub-criterion were added to get final Sustainability Index value.
SI= max 𝑿𝒊𝒋𝒘𝒊𝙭𝒋 𝒋 = 𝟏,…𝒏𝒎𝒊=𝟏
Where, SI = total score
𝙭𝒋 = Weight of number of sub criteria
𝒘𝒊 = weight of the criterion and
𝑿𝒊𝒋 = normalized score for the criterion.
Chapter 4 Sustainability Assessment For Urban Water Management System 107
4.2.6 SAMPLE CALCULATION FOR SUSTAINABILITY INDEX
Sample calculation for sub criteria access to water supply is shown below:
Step: 1 Composite Weight = weight of sub criteria × weight of criteria
= 0.2 × 0.24
= 0.048
Step: 2 Normalized value = Actual data/ Service level benchmark data
= 56/100
= 0.56
Step: 3 Final value = normalized value × average of expert weight
= 0.56 × 0.2
= 0.112
Step: 4 Addition of final values of all social criteria results into social index.
4.2.6.1 SOCIAL CRITERIA
Criteria
Average
weight of
expert view
Composite
Weight
Actual
data
Service
level
benchmark
Normalised
value Final value
Access to
water supply 0.2 0.048
56%
100%
0.56 0.112
Access to
sanitation 0.15 0.036
26.73%
100%
0.2673 0.040
Service
complaint 0.14 0.0336
417
no/year
NIL
2.3 X10⁻3 3.22 X10⁻4
Flood prone
area 0.13 0.0312
239 no
/year
NIL
4.18 X10⁻3 5.43X10⁻4
Supply hours
daily 0.17 0.0408
3
hours/day
24
hours/day
0.125 0.021
Water
availability 0.21 0.0504
180
LPCD
135 LPCD
1.33 0.279
Table 4.3 Weightage of sub criteria and index value of social criteria
The above table 4.3 and chart 4.2 represents water availability to the consumer is very good
comparing to access to water supply in terms of percentage population.
Chapter 4 Sustainability Assessment For Urban Water Management System 108
Chart 4.2 Graphical presentations of Social Index value
4.2.6.2 ECONOMIC CRITERIA
Criteria Average Weight Actual
Data
Standard Data Normalised
Value
Final
Capital
Investment
0.29 0.0696 56.00 % 100 % Population
should Get Good
Quality Water
0.56 0.1624
Operation
and Maintain
0.5 0.12 58.88
Crore
(2008-
09)
100 % Capital
Investment should
be recovered
(59.27 crore)
0.9935 0.49675
Research and
Development
Investment
0.21 0.0528 0 20 % 0 0
Total 0.65915
Table 4.4 Weightage of sub criteria and index value of Economic criteria
00.05
0.10.15
0.20.25
0.3
ACCESS TO WATER SUPPLY
ACCESS TO SANITATION
SERVICE COMPLAINTS
FLOOD RISK
SUPPLY HOURS DAILY
WATER AVAILABILITY
SOCIAL CRITERIA
INDEX VALUES
Chapter 4 Sustainability Assessment For Urban Water Management System 109
Chart 4.3 Graphical presentations of Economic Index value
4.2.6.3 ENVIRONMENTAL CRITERIA
Criteria Average Compo
site
Weight
Actual
Data
Standard Data Normalised
Value
Final
Water Withdrawal 0.14 0.0392 692 MLD 700 MLD 1.011 0.141
Energy Consumption 0.11 0.0308 73464058
(KWH)
Max. Energy
should be used
from Renewable
Sources
1.36 X 10-8
1.496 x
10-9
Amount of waste water
treated
0.12 0.0336 94 % 100 % of the
waste water
generated
0.94 0.1128
Waste Water Treatment
Performance
0.11 0.308 Acc. Std.
Data
WHO Standard
100 %
1 0.11
Water Reuse 0.12 0.0336 0% 100 % 0 0
Recycling of Nutrients
and Sludge Reuse
0.1 0.028 0% 100 % 0 0
Storm Water Area
covered under pipe
network
0.1 0.028 45.22 % 100 % 0.4522 0.4522
Rain Water Harvesting
Recharging
0.1 0.028 0.50 % 100% 0.005 0.005
Salination Ingress 0.1 0.028 3.88 % Should be
minimum
0.2577 0.2577
Total 0.4351
Table 4.5 Weightage of sub criteria and index value of Environmental criteria
00.10.20.30.40.5
CAPITAL INVESTMENT
OPERATION AND MAINTAINENCE
RESEARCH & DEVELOPMENT INVESTMENT
ECONOMIC CRITERIA
INDEX VALUES
Chapter 4 Sustainability Assessment For Urban Water Management System 110
Chart 4.4 Graphical Presentations for Environmental Index Value
The table 4.4 and chart 3.4 reveals operation and maintenance cost fully recovered whereas
research and development fund is nil that need to be improved.
The table 4.5 and chart 3.5 shows more sustainable water supply system can be develop by
employing water reusing/ nutrient recycling/rain water recharging facilities and by
developing usage of renewable energy sources.
4.2.6.4 ENGINEERING CRITERIA
Criteria Average Weight Actual
Data
Standard
Data
Normalised
Value
Final
Metered
connection 0.4 0.0864 0.41% 100% 0.0041 0.00164
Service
interruption and
water losses
0.6 0.1536 20% MINIMUM 0.05 0.03
Total 0.03164
Table 4.6 Weightage of sub criteria and index value of Engineering criteria
00.020.040.060.08
0.10.120.140.16
WATER …
ENERGY …
AMOUNT OF …
WASTE WATER …
WATER REUSERECYCLING OF …
STORM WATER -…
RAIN WATER …
SALINATION INGRESS
ENVIRONMENTAL CRITERIA
INDEX VALUES
Chapter 4 Sustainability Assessment For Urban Water Management System 111
Chart 4.5 Graphical presentations for Engineering Index value
The above table 4.6 and chart 4.5 represents both engineering sub criteria need to be
improved. It is found that engineering criteria has more potential to develop sustainable
system by making whole water supply network metered and by accurately measuring water
losses or conducting water audit.
4.2.6.5 COMPOSITE AGGREGATE INDEX
Main Criteria Final index value
for individual
criteria
Weight of
main
criteria
SI value for UWM
Social criteria 0.453 0.24 0.1087
Economic criteria 0.65915 0.24 0.158196
Environment criteria 0.435 0.28 0.1218
Engineering criteria 0.03164 0.24 0.0075936
Sustainability Index 0.396289
Table 4.7 Composite aggregate Index value for all criteria
The table 4.7 and chart 4.6 represents Social, Economic, Environmental, Engineering Indexes
are 0.453, 0.659, 0.435, 0.03164 respectively. The composite sustainability index for water
management system of Surat city is 0.396289. The major reason found is poor performance
of engineering criteria. The individual index also reflects engineering criteria is having very
00.005
0.010.015
0.020.025
0.03
METERED CONNECTION
SERVICE INTERRUPTION AND
WATER LOSSES
ENGINEERING CRITERIA
INDEX VALUES
Chapter 4 Sustainability Assessment For Urban Water Management System 112
low index value 0.03164. Hence, it is concluded that by improving the system for engineering
criteria composite aggregate index can also be increased. Based on this preliminary
sustainability assessment in the next phase work is carried out to improve engineering
criteria. Therefore, further research has been done on reduction of water losses from the
system.
Chart 4.6 Graphical presentation of composite aggregate Index
0
0.05
0.1
0.15
0.2SOCIAL CRITERIA
ECONOMIC CRITERIA
ENVIRONMENT CRITERIA
ENGINEERING CRITERIA
MAIN CRITERIA
INDEX VALUES