Water resources assessment for city area
Modelling and Simulation
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
Water Resources Assessment for City Area
M. Yanuar J. Purwanto and Sutoyo
Department of Civil and Environmental Engineering
Bogor Agricultural University
Yan_tta@yahoo.com
Abstract— Many cities face problem scarcity of fresh and
clean water now. However, our ability to correctly assess
and predict city water availability, use and balance is still
quite limited. City-water model is developed and used to
assess water resources using system dynamics approach. It
has shown that: (a) For economic growth scenarios, there is
a strong relationship between the water resources and future
industrial growth, and (b) In the existing condition of
industries in Indonesia, cities the water pollution is the most
important future water issue on the global level. Solutions
for water problems are at the city level and the regional
presented in this paper. City and regional characteristics of
the water resources considerable increase in the complexity
of the model. First results indicate that City-water model has
a potential to identify water-related issues of domestic
priority and assist policy makers in evaluating various
sustainable solutions for sustainable water resources
management.
Keywords- water demand, city, regional, assessment, water
resources
I.
INTRODUCTION
The water-use categories covered in general include:
public water supply, domestic, commercial, industrial,
mining, irrigation, livestock and animal specialties,
thermoelectric power, and hydroelectric power. This paper
only for the domestic or residential sector, in with the
relative water use by this sector has also change over time.
Population and class of income will affect to the total water
demand in residential area (Pawitan et al, 1994).
In USA, residential water use includes water used for
household purposes such as drinking, food preparation,
bathing, washing clothes and dishes, flushing toilets, car
washing, and watering lawns and gardens. Households
include single and multi-family dwellings, such as
apartments, condominiums, and small mobile home parks.
Residential use is separated into inside household uses
(bathing, flushing toilets, laundry, cleaning, and cooking)
and outside household uses (lawn and garden watering, car
washing, and pools). Inside uses tend to be consistent year
round while outside uses tend to increase during specific
seasons, usually summer, depending on the type of climate.
City water demand is equal with a total amount of water
uses among city uses for total population per capita, and
others consumptions in the city. Based on the standard water
demand by Gupta (1989) it was determined that for
residential area is required as much as 60 gallon per capita
day (Table 1). White et al., (1972) reported water demand
using common public outlet is about 15 – 90 liter/person/day
and water demand using individual outlet is about 30 – 300
liter/person/day. From these number of water demands, there
is evidence that within population in the residential area, at
least three different classes of income which consume water
differently from each class to the others.
Table 1. Daily water demand per capita
No.
1
2
3
4
5
Water use
Demand (gcd)
Household
Commercial
Industry
Public
Loss
Total
60
20
45
15
10
150
Percent of
total (%)
40
13
30
10
7
100
Source : Gupta (1989), gcd= galon capita/day
Water use can be determined either for site-specific
facilities or for categories of water use for a given area.
Determining site-specific water use involves water
withdrawal, delivery, release, and return-flow data. Area
estimates are based on coefficients relating water use to
another characteristic, such as number of employees, and
applying it to an inventory of site-specific users or by
measuring a statistical sample of the user population.
Winrock (1992), Directorate General of Public Work
Cipta Karya set for domestic water needs of the rural
community is 45 lcd (liter capita / day) and for the city of 60
lcd. Main factors that determine the amount of water the city
needs is the number of population and the accuracy of the
projected population will be very important to predict the
water needs in the future (Pawitan et al, 1994).
The amount of water needs for each industry is not the
same to the domestic. It depends on several factors, among
the number of employees, work units, the length of working
hours, and others. To determine the needs for industrial
water supply in urban areas can be categorized into three
types based on the number of usage, big industry around 151
- 350 m3/hari, medium industry are around 51 - 150 m3/hari,
and small industries ranging from 5 to 50 m3 / day
(Purwanto, 1995).
The objective of this study is to develop water
assessment model especially water demand analysis of city
for basin area.
template provides authors with most of the formatting
specifications needed for preparing electronic versions of
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
user population. Coefficients are most reliable when they are
applied to uniform groups of users from which the
coefficients were developed, such as the same income groups
identified by the Indonesian governmental statistics book.
With the same assumption, water demand for industry can be
calculated using the above formula by replacing population
as unit of industry, and also adopting the class of industry as
for person’s income parameter..
their papers. All standard paper components have been
specified for three reasons: (1) ease of use when formatting
individual papers, (2) automatic compliance to electronic
requirements that facilitate the concurrent or later production
of electronic products, and (3) conformity of style
throughout a conference proceedings. Margins, column
widths, line spacing, and type styles are built-in; examples of
the type styles are provided throughout this document and
are identified in italic type, within parentheses, following the
example. PLEASE DO NOT RE-ADJUST THESE
MARGINS. Some components, such as multi-leveled
equations, graphics, and tables are not prescribed, although
the various table text styles are provided. The formatter will
need to create these components, incorporating the
applicable criteria that follow.
II.
Data and Location of Study.
Cilegon city is selected for this study. Inventories of all
users were collected at the KTI costumers. KTI is a local
clean water company for residential and industrial uses. To
have accurate data, inventory of reported data was
investigated. Secondary data acquisition involves
compilation evaluation and analysis of measured data
reported to the KTI headquarters at Cilegon. Surveyed data
were collected in response to a specific need for the data in
1999 to 2000.
Residential and industry water uses are determined
primarily through the use of coefficients of use per unit of
water demand. Reasonable per capita (or unit o\industry)
value were determined as 30 liter/person/day base on White
et al., (1972). Coefficient values were evaluated by
reviewing recorded KTI reports. The actual measurements
are done by reading existing meters and using time totalizes
to record flowing duration. Possible criteria for developing
stratified subsets include the number of households in the
unit or size of lot. Residents may be surveyed to determine
other important criteria, such as income distribution and
income class.
Stratified-random sampling is one form of sampling that
offers considerable efficiency in water-use estimation and
involves separating sites with similar water-use
characteristics into groups or strata. Stratified-random
sampling can increase the reliability of estimates on the basis
of sample "means." The technique is used when there are
known groups with particular water-use characteristics
(Stratification divides the population into internally similar
groups).
THE METHOD
Methods of estimating water use vary widely. The
use of consistent methods, estimation techniques,
terminology, and definitions for water-use data acquisition
help ensure that the water-use estimates will meet certain
requirements. For residential area, water demand was
derived from the formula of evapotranspiration by Penman
Method as follows:
ETc ETo Kc (mm/day) ………………. (1)
ETc 0.116 ETo Kc (l/sec/ha) ……. (2)
where
ETc
ETo
Kc
:
= Actual evapotranspiration of crop,
mm/day
= Potential Evapotranpiration by Penman,
mm/day
= Crop coefficient
By the same common sense that population in the citty area
have their specific water demand as crops population, water
demaqnd for people can be formulated as follows:
y
Person
( pP P) KaP CP and
ETc Ha 0.116 ETo Kc .
where :
ETc for crop y for person
Crop Area (Ha) Residential Area (pP x P)
Consumtive Use (Eto) Individual Use (KaP)
Crop Coefficient (Kc) Coefficient of Income class
(CP)
Water Demand Model
Mathematical equation model for water demand built on
summation of water demand for each user. Model for the
water demand of domestic population consists of several
parameters, the percentage of social level population, the
number of population, the water needs of the average
population and the constant of the respective social level.
Model of the water demand of industry consists of several
parameters, the percentage of type of industry, the number of
industries, the water needs of the industry average and the
constant of each type of industry. Development of the
community not only related to population growth but must
also be followed by the adequate of employment. Increasing
of employment is subject to the availability of water storage.
Water is needed to operate the sector of employment and
meet the needs of domestic water in the area. The success of
Then, water demand in the residential area with total
population (P), standard individual use (KaP), percentage of
class income covers m class incomes (pP), the water
demand is:
m
y
Person
pi P P KaP Ci P (3)
i 1
This water demand is an area estimates based on
coefficients relating water use to another characteristic of
person’s income CiP and applying it to an inventory of sitespecific users and by measuring a statistical sample of the
337
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
the development community on region occurred when the
water for domestic and employment available, so that the
predicted water demand become important in the
development of the regional planning. Model built with the
framework that are mathematically related of the needs of
water and then simulated so that the output form of the water
demand for years to come.
population with highest income reach 50% of population.
This number is almost three times than of 1999. It is means
that, water availability give significant contribution in
increasing number of highest income people in the city.
IV. Conclusions
As conclussion of this study, the model of water demand
for residential area in Cilegon Districts was established. The
model consists of three water demand classes based on their
income levels. Actual water allocations for residential area in
Cilegon district, Banten Province, were used for the model
calibration process. The model can be operated for the future
water demand prediction using population growth and the
income classification. The established model was used for
predicting the amount of water demand in the future with the
advantage as for guiding the local government in providing
water for the residential area in relation with the effort to
increase individual income level of the citizen. For example
in 2020, number of the highest income in the city will
increase almost three time when industrial water sector in
available almost 6 times than water demand in 1999.
III. RESULT AND DISCUSSION
Water uses for residential area using waterflow meter
compiled at the KTI Headquarter office were use for
calibration proses by trial and error. The water demand
parameter for 1999 are as follows: a) Total Population in
1999 = 278 462 person, b) Total Actual water demand in
1999 = 8 127 800 liter, c) Standard Water demand is 30
liter/person/day, and d) Population Percentage base on
income classification are 16.15%, 50.26% and 33.59% for
P1P, P2P and P3P respectively. Base on those condition, CiP
for The three income classes are 2.58, 1.47,0.51 for C1P,
C2P and C3P respectively. As the result, total water demand
in 1999 was found as about 8 207 500 liter. Validation of the
model was done by using set data of 2000 and 2001 as
shown in Table 2.
REFERENCES
[1]
[2]
Table 2. Validation Model residential Water Demand of
Cilegon District in 2000 and 2001
Water Demand
Water Demand
[3]
R2
Year C1P
C2P
C3P
Model
Actual
2000 2.58
1.47
0.51
9 619 100
9 483 100
0.9857
2001 2.58
1.47
0.51
11 344 400
10 110 000
0.8849
[4]
[5]
Note: Unit for the water demand is liter/day.
[6]
By using the same method, water user for industry in
Cilegon city were calculated by considering: a) Number
total industry in 1999= 58 units, b) Total actual industry
water demand = 89 211 476.92 liter, c) Standard water
demand is 100 liter/unit/day with coeff demand for each type
of industry are: 2.5, 1.0, and 0.25 for large, medium and
small industries respectively, and d) percentages of
population of industry are 39.35%, 8.2% and 52.45% for
large, medium and small industries respectively. And the
total water demand for industrial sector in 1999 is
121676940 liter.
[7]
Cilegon Statistic Bureau. 2002. Cilegon in Figure 2002. Cilegon
Gupta, R., 1989. Hydrologi and Hydraulic System. Prentice Hall Inc.
New York.
Linsley, R.K., M.A Kohler and J.J.H Paulus. 1982. Hydrology for
Engineers. McGraw Hill Inc. New York.
Martin, L. A. 1997. First Step, MIT System Dynamics in Education
Project. Massachusetts Institute of Technology. Massachusetts. USA
Pawitan, H. 1995. Analysis method to predict erosion and
sedimentation on watershed. Puslitbang Pengairan, Bandung.
Purwanto, M.Y.J. 1995. Water Demand for Industry, Village, and
City. Seminar on Water Demand and Developing Country. Tokyo .
Japan.
Sugawara, M. 1961. On the Analysis of Runoff Structure about
Several Japanese. River. Japanese Journal of Geophysic. Vol 4 No.2
March 1961. The Science Council of Japan. Japan.
.
For industrial water demand, validation of the model reach
correlation value more than 0.8 for two years validation
processes (2000 and 2001).
Model Aplication
The established model was used for predicting the
amount of water demand in the future. Based on the annual
population in 1999 to 2001, population growth in Cilegon
district was predicted as the following equatiuons, y = 21
048 ln(x) + 278 970. The prediction of population water
demand annually in 2020 is 16958971 liter and for industri is
608384700 liter. This amount of water reflect number
338
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
Water Resources Assessment for City Area
M. Yanuar J. Purwanto and Sutoyo
Department of Civil and Environmental Engineering
Bogor Agricultural University
Yan_tta@yahoo.com
Abstract— Many cities face problem scarcity of fresh and
clean water now. However, our ability to correctly assess
and predict city water availability, use and balance is still
quite limited. City-water model is developed and used to
assess water resources using system dynamics approach. It
has shown that: (a) For economic growth scenarios, there is
a strong relationship between the water resources and future
industrial growth, and (b) In the existing condition of
industries in Indonesia, cities the water pollution is the most
important future water issue on the global level. Solutions
for water problems are at the city level and the regional
presented in this paper. City and regional characteristics of
the water resources considerable increase in the complexity
of the model. First results indicate that City-water model has
a potential to identify water-related issues of domestic
priority and assist policy makers in evaluating various
sustainable solutions for sustainable water resources
management.
Keywords- water demand, city, regional, assessment, water
resources
I.
INTRODUCTION
The water-use categories covered in general include:
public water supply, domestic, commercial, industrial,
mining, irrigation, livestock and animal specialties,
thermoelectric power, and hydroelectric power. This paper
only for the domestic or residential sector, in with the
relative water use by this sector has also change over time.
Population and class of income will affect to the total water
demand in residential area (Pawitan et al, 1994).
In USA, residential water use includes water used for
household purposes such as drinking, food preparation,
bathing, washing clothes and dishes, flushing toilets, car
washing, and watering lawns and gardens. Households
include single and multi-family dwellings, such as
apartments, condominiums, and small mobile home parks.
Residential use is separated into inside household uses
(bathing, flushing toilets, laundry, cleaning, and cooking)
and outside household uses (lawn and garden watering, car
washing, and pools). Inside uses tend to be consistent year
round while outside uses tend to increase during specific
seasons, usually summer, depending on the type of climate.
City water demand is equal with a total amount of water
uses among city uses for total population per capita, and
others consumptions in the city. Based on the standard water
demand by Gupta (1989) it was determined that for
residential area is required as much as 60 gallon per capita
day (Table 1). White et al., (1972) reported water demand
using common public outlet is about 15 – 90 liter/person/day
and water demand using individual outlet is about 30 – 300
liter/person/day. From these number of water demands, there
is evidence that within population in the residential area, at
least three different classes of income which consume water
differently from each class to the others.
Table 1. Daily water demand per capita
No.
1
2
3
4
5
Water use
Demand (gcd)
Household
Commercial
Industry
Public
Loss
Total
60
20
45
15
10
150
Percent of
total (%)
40
13
30
10
7
100
Source : Gupta (1989), gcd= galon capita/day
Water use can be determined either for site-specific
facilities or for categories of water use for a given area.
Determining site-specific water use involves water
withdrawal, delivery, release, and return-flow data. Area
estimates are based on coefficients relating water use to
another characteristic, such as number of employees, and
applying it to an inventory of site-specific users or by
measuring a statistical sample of the user population.
Winrock (1992), Directorate General of Public Work
Cipta Karya set for domestic water needs of the rural
community is 45 lcd (liter capita / day) and for the city of 60
lcd. Main factors that determine the amount of water the city
needs is the number of population and the accuracy of the
projected population will be very important to predict the
water needs in the future (Pawitan et al, 1994).
The amount of water needs for each industry is not the
same to the domestic. It depends on several factors, among
the number of employees, work units, the length of working
hours, and others. To determine the needs for industrial
water supply in urban areas can be categorized into three
types based on the number of usage, big industry around 151
- 350 m3/hari, medium industry are around 51 - 150 m3/hari,
and small industries ranging from 5 to 50 m3 / day
(Purwanto, 1995).
The objective of this study is to develop water
assessment model especially water demand analysis of city
for basin area.
template provides authors with most of the formatting
specifications needed for preparing electronic versions of
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
user population. Coefficients are most reliable when they are
applied to uniform groups of users from which the
coefficients were developed, such as the same income groups
identified by the Indonesian governmental statistics book.
With the same assumption, water demand for industry can be
calculated using the above formula by replacing population
as unit of industry, and also adopting the class of industry as
for person’s income parameter..
their papers. All standard paper components have been
specified for three reasons: (1) ease of use when formatting
individual papers, (2) automatic compliance to electronic
requirements that facilitate the concurrent or later production
of electronic products, and (3) conformity of style
throughout a conference proceedings. Margins, column
widths, line spacing, and type styles are built-in; examples of
the type styles are provided throughout this document and
are identified in italic type, within parentheses, following the
example. PLEASE DO NOT RE-ADJUST THESE
MARGINS. Some components, such as multi-leveled
equations, graphics, and tables are not prescribed, although
the various table text styles are provided. The formatter will
need to create these components, incorporating the
applicable criteria that follow.
II.
Data and Location of Study.
Cilegon city is selected for this study. Inventories of all
users were collected at the KTI costumers. KTI is a local
clean water company for residential and industrial uses. To
have accurate data, inventory of reported data was
investigated. Secondary data acquisition involves
compilation evaluation and analysis of measured data
reported to the KTI headquarters at Cilegon. Surveyed data
were collected in response to a specific need for the data in
1999 to 2000.
Residential and industry water uses are determined
primarily through the use of coefficients of use per unit of
water demand. Reasonable per capita (or unit o\industry)
value were determined as 30 liter/person/day base on White
et al., (1972). Coefficient values were evaluated by
reviewing recorded KTI reports. The actual measurements
are done by reading existing meters and using time totalizes
to record flowing duration. Possible criteria for developing
stratified subsets include the number of households in the
unit or size of lot. Residents may be surveyed to determine
other important criteria, such as income distribution and
income class.
Stratified-random sampling is one form of sampling that
offers considerable efficiency in water-use estimation and
involves separating sites with similar water-use
characteristics into groups or strata. Stratified-random
sampling can increase the reliability of estimates on the basis
of sample "means." The technique is used when there are
known groups with particular water-use characteristics
(Stratification divides the population into internally similar
groups).
THE METHOD
Methods of estimating water use vary widely. The
use of consistent methods, estimation techniques,
terminology, and definitions for water-use data acquisition
help ensure that the water-use estimates will meet certain
requirements. For residential area, water demand was
derived from the formula of evapotranspiration by Penman
Method as follows:
ETc ETo Kc (mm/day) ………………. (1)
ETc 0.116 ETo Kc (l/sec/ha) ……. (2)
where
ETc
ETo
Kc
:
= Actual evapotranspiration of crop,
mm/day
= Potential Evapotranpiration by Penman,
mm/day
= Crop coefficient
By the same common sense that population in the citty area
have their specific water demand as crops population, water
demaqnd for people can be formulated as follows:
y
Person
( pP P) KaP CP and
ETc Ha 0.116 ETo Kc .
where :
ETc for crop y for person
Crop Area (Ha) Residential Area (pP x P)
Consumtive Use (Eto) Individual Use (KaP)
Crop Coefficient (Kc) Coefficient of Income class
(CP)
Water Demand Model
Mathematical equation model for water demand built on
summation of water demand for each user. Model for the
water demand of domestic population consists of several
parameters, the percentage of social level population, the
number of population, the water needs of the average
population and the constant of the respective social level.
Model of the water demand of industry consists of several
parameters, the percentage of type of industry, the number of
industries, the water needs of the industry average and the
constant of each type of industry. Development of the
community not only related to population growth but must
also be followed by the adequate of employment. Increasing
of employment is subject to the availability of water storage.
Water is needed to operate the sector of employment and
meet the needs of domestic water in the area. The success of
Then, water demand in the residential area with total
population (P), standard individual use (KaP), percentage of
class income covers m class incomes (pP), the water
demand is:
m
y
Person
pi P P KaP Ci P (3)
i 1
This water demand is an area estimates based on
coefficients relating water use to another characteristic of
person’s income CiP and applying it to an inventory of sitespecific users and by measuring a statistical sample of the
337
AFITA 2010 International Conference, The Quality Information for Competitive Agricultural Based Production System and Commerce
the development community on region occurred when the
water for domestic and employment available, so that the
predicted water demand become important in the
development of the regional planning. Model built with the
framework that are mathematically related of the needs of
water and then simulated so that the output form of the water
demand for years to come.
population with highest income reach 50% of population.
This number is almost three times than of 1999. It is means
that, water availability give significant contribution in
increasing number of highest income people in the city.
IV. Conclusions
As conclussion of this study, the model of water demand
for residential area in Cilegon Districts was established. The
model consists of three water demand classes based on their
income levels. Actual water allocations for residential area in
Cilegon district, Banten Province, were used for the model
calibration process. The model can be operated for the future
water demand prediction using population growth and the
income classification. The established model was used for
predicting the amount of water demand in the future with the
advantage as for guiding the local government in providing
water for the residential area in relation with the effort to
increase individual income level of the citizen. For example
in 2020, number of the highest income in the city will
increase almost three time when industrial water sector in
available almost 6 times than water demand in 1999.
III. RESULT AND DISCUSSION
Water uses for residential area using waterflow meter
compiled at the KTI Headquarter office were use for
calibration proses by trial and error. The water demand
parameter for 1999 are as follows: a) Total Population in
1999 = 278 462 person, b) Total Actual water demand in
1999 = 8 127 800 liter, c) Standard Water demand is 30
liter/person/day, and d) Population Percentage base on
income classification are 16.15%, 50.26% and 33.59% for
P1P, P2P and P3P respectively. Base on those condition, CiP
for The three income classes are 2.58, 1.47,0.51 for C1P,
C2P and C3P respectively. As the result, total water demand
in 1999 was found as about 8 207 500 liter. Validation of the
model was done by using set data of 2000 and 2001 as
shown in Table 2.
REFERENCES
[1]
[2]
Table 2. Validation Model residential Water Demand of
Cilegon District in 2000 and 2001
Water Demand
Water Demand
[3]
R2
Year C1P
C2P
C3P
Model
Actual
2000 2.58
1.47
0.51
9 619 100
9 483 100
0.9857
2001 2.58
1.47
0.51
11 344 400
10 110 000
0.8849
[4]
[5]
Note: Unit for the water demand is liter/day.
[6]
By using the same method, water user for industry in
Cilegon city were calculated by considering: a) Number
total industry in 1999= 58 units, b) Total actual industry
water demand = 89 211 476.92 liter, c) Standard water
demand is 100 liter/unit/day with coeff demand for each type
of industry are: 2.5, 1.0, and 0.25 for large, medium and
small industries respectively, and d) percentages of
population of industry are 39.35%, 8.2% and 52.45% for
large, medium and small industries respectively. And the
total water demand for industrial sector in 1999 is
121676940 liter.
[7]
Cilegon Statistic Bureau. 2002. Cilegon in Figure 2002. Cilegon
Gupta, R., 1989. Hydrologi and Hydraulic System. Prentice Hall Inc.
New York.
Linsley, R.K., M.A Kohler and J.J.H Paulus. 1982. Hydrology for
Engineers. McGraw Hill Inc. New York.
Martin, L. A. 1997. First Step, MIT System Dynamics in Education
Project. Massachusetts Institute of Technology. Massachusetts. USA
Pawitan, H. 1995. Analysis method to predict erosion and
sedimentation on watershed. Puslitbang Pengairan, Bandung.
Purwanto, M.Y.J. 1995. Water Demand for Industry, Village, and
City. Seminar on Water Demand and Developing Country. Tokyo .
Japan.
Sugawara, M. 1961. On the Analysis of Runoff Structure about
Several Japanese. River. Japanese Journal of Geophysic. Vol 4 No.2
March 1961. The Science Council of Japan. Japan.
.
For industrial water demand, validation of the model reach
correlation value more than 0.8 for two years validation
processes (2000 and 2001).
Model Aplication
The established model was used for predicting the
amount of water demand in the future. Based on the annual
population in 1999 to 2001, population growth in Cilegon
district was predicted as the following equatiuons, y = 21
048 ln(x) + 278 970. The prediction of population water
demand annually in 2020 is 16958971 liter and for industri is
608384700 liter. This amount of water reflect number
338