Application of West Java Water Sustainability
4.2.1 Obtaining Sub ‐ index Values
As outlined in Section 2.4.2, the methods used to obtain sub‐indices are ranking, continuous rescaling, percentage of annual differences over consecutive years, categorical scale and distance to reference.
The ranking method will not be used in this study, as this method provides only a rank for each
indicator and sub‐indicator, and does not provide information on the conditions of indicators
and sub‐indicators. In the WJWSI, information on these conditions is required to further
formulate necessary policies and programs for improving overall water resource management.
The percentage of annual differences method will not be used for the WJWSI due to lack of
data. To be useful, this method requires several years of data, which is not available in West
Java. The rationale for not using the distance to reference method was because this method
requires prior knowledge of the values of indicators, so they can be used as reference values.
With regards to water resource management in West Java, such indicators with known values
are not available.
The continuous rescaling and the categorical scale methods were chosen because they are
able to provide information on the conditions of WJWSI indicators and sub‐indicators, which is
reflected in their respective sub‐indices. Also, these methods were used, as required
information to use these methods was also available. Based on the characteristics of available
data, three groups of indicators and sub‐indicators were identified to compute their sub‐index
values.
The first group of indicators and sub‐indicators are Water Availability, Land Use Changes, Coverage, Education and Sanitation. The sub‐index values for this group were obtained using
the continuous rescaling method (Eq. (2.2b)). Eq. (2.2b) is reproduced below as Eq. (4.1).
Indicators and sub‐indicators of the second group are Water Quality, Water Demand, Water Loss, Poverty and Health Impact. The sub‐index values for this group were obtained using the
modified continuous rescaling method (Eq. (2.3b)). Eq. (2.3b) is reproduced below as Eq. (4.2).
min max min 100 i i X X S X X − = × − (4.1) min max min 100 i 100 i X X S X X ⎛ − ⎞ = −⎜ × ⎟ − ⎝ ⎠
(4.2)
where Si is the sub‐index value for indicator i, Xi is the actual value for indicator i, and Xmin and Xmax are the minimum and maximum threshold values of the indicator.
The third group consists of three indicators: Information Disclosure, Governance Structure and Law Enforcement. Due to their qualitative nature, minimum and maximum thresholds to
calculate the sub‐indices of these indicators and sub‐indicators using the continuous rescaling
method are not available. Therefore, for these indicators, the categorical scale was used to
obtain their sub‐indices, as shown in Eq. (4.3). A quartile scale was proposed in Eq. (4.3). This
equation was modified from Eq. (2.5). 0 – < 25 if Xi meets criteria 1 Si = 25 – < 50 if Xi meets criteria 2 (4.3) 50 – < 75 if Xi meets criteria 3 75 – 100 if Xi meets criteria 4
where Xi is the actual condition (similar to actual values for the non‐categorical indicators and sub‐indicators) assessed in a particular catchment. The four criteria (1 to 4) that are used to
obtain sub‐indices for each of these three categorical indicators and sub‐indicators are defined
as follows:
Information Disclosure
The Information Disclosure indicator examines the availability and accessibility of key data
related to water resource management, for public use. Table 4.1 shows the quartile scale that
was proposed to quantify the sub‐index for this indicator, with its criteria. Key data include
rainfall, population, water quality, water use, coverage, water losses, education, poverty,
sanitation, water‐related diseases and land use.
Table 4.1 Criteria for sub‐index values of Information Disclosure
Criteria Sub‐index
Few key data (25% or less) are available 0 – <25
Key data are available, but only a few are accessible through
the internet
25 – <50 Key data are available, accessible, but not regularly updated 50 – <75 Key data are available, accessible and regularly updated 75 – 100
Governance Structure
Governance Structure analyses the governance structure of water‐related institutions in West
Java, particularly with respect to job descriptions, and overlaps among different institutions.
Table 4.2 shows the criteria, based on the quartile scale, which was proposed to quantify the
sub‐index of this indicator.
Table 4.2 Criteria for sub‐index values of Governance Structure
Criteria indexSub‐
Only few institutions (25% or less) responsible for managing water resources
have clear structures
0 – <25 All institutions responsible for managing water resources have clear
structures
25 – <50
Structure of the institutions are clear, but overlap of tasks occur 50 – <75 Clear structure and no overlap of tasks among different institutions 75 – 100
Law Enforcement
This indicator considers the enforcement of regulation on water resources, particularly on
stream quality. Table 4.3 shows the criteria, based on the quartile scale, which was proposed
to quantify the sub‐index for Law Enforcement.
Table 4.3 Criteria for sub‐index values of Law Enforcement
Criteria Sub‐
index
Procedure for enforcement is not available 0 – <25
Procedure for enforcement is available, but no supporting resources
(human, budget)
25 – <50 Procedure for enforcement and supporting resources (human, budget) are
available, but not implemented
50 – <75 Procedure for enforcement and supporting resources (human, budget) are
available, and implemented
75 – 100