Observed climate change could affect water availability in the future. Changes also occurred Kupang city in recent decades, an increase in the magnitude of the damage caused by drought due to climate change. In an attempt to explore the effects of drought can be aggravated by climate change. in this paper, the author will be analyze impact of changes in the water balance in Kupang city. To achieve that, the author will use the procedure consists of two procedures: Temperature and precipitation are modeled under two typical emission A1FI and B1 scenarios evaluated in this study for future projections in Kupang, discharge simulations using rainfall Mock generated daily rainfall and water balance monthly Data analysis WEAP (water Evaluation and Planning System) based simulation Mock. Due to the significant uncertainty involved in forecasting future water consumption and water yield, the author will use the three scenarios assumed water consumption and water three outcome scenarios. Three scenarios of water consumption, ie, "Low", "Medium" and "High" in accordance with the expected number of water consumption. Disposal obtained from mock simulations during the simulation period. Finally, the water balance analysis conducted by WEAP based on a combination of the three scenarios of water consumption. With this procedure, it is possible to explore different scenarios of water consumption and water results and the results of this study can be used to establish the proper planning to minimize the impact of drought on water availability to support water requirement due to climate change in Kupang city.

1. The 4th International Seminar Department of Environmental Engineering
Department of Environmental Engineering, Institut Teknologi Sepuluh Nopember
Public Health Program Study, Medical Faculty, Udayana University
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Impact of Future Climate Change on water availability
in Kupang City
Willem Sidharno a, b *
, Ali Masduqi a
, Umboro Lasminto c
a
Dept.of Enviroment Engineering, Institut Teknologi Sepuluh November
b
Ministry of Public Work Republic of Indonesia, Directorate General of Water Resources
c
Dept.of Civil Engineering, Institut Teknologi Sepuluh November
* Corresponding author present address: Institut Teknologi Sepuluh November,
Dept.of Enviroment Engineering,Indonesia
Email : willem.sidharno11@mhs.enviro.its.ac.id
Abstract
Climate change may affect the hydrologic system that can affect the availability of water.
Kupang city is a city that is high temperatures and low rainfall, by making climate change
SRES scenarios A1FI and B1, from the results of analysis found that the effect of climate
change on temperature rise also led to increased evapotranspiration and result in increased
precipitation. The effect can be calculated with F.J.Mock method, with the results of the
analysis increased runoff and discharge in the watershed since the year 2013 to 2099. the
increasing number of people each year, the need for water also increased, by using water
demand scenarios of low, medium and high, combined with climate change scenarios, the
analysis of the results indicated that the availability of water is more and reached 593.98
m3/second, but in April-October there is a shortage of water to -49 m3/second. This is due to
the high water demand and population increase.
Keywords: Climate change, water availability, SRES, temperature, MOCK, water demand,.
1. Introduction
Global warming is clearly evidenced by the increase in the average temperature of the earth
and ocean temperatures, widespread melting of snow and glaciers, and sea level rise earth,
which has been observed and measured. Studies on the effects of anthropogenic climate
change has found that the magnitude and frequency of intense rainfall is expected to
increase during the century (Zachary, et al., 2012). Climate change has become a very
important environmental issue, and one that will challenge management practices of existing
water resources in many ways such as floods and droughts (Zhang, et al., 2012). From the
results of existing research, climate change impacts will affect hydrological processes in the
future (Qin Ju, et al., 2012). Climate change and land use patterns affect the management of
the existing water and forcing water managers to develop new techniques of water
management in response to changes in the environment (Philip, et al., 2012). It is expected
that the availability of clean water that can be used in Central Asia, South Asia, East Asia,
Southeast Asia will decline in 2050. In particular, the neighboring areas of the river will have
serious consequences (Synthesis Report of the IPCC Fourth Assessment Report, 2007). In
fact, the evidence of climate change has been found in various parts of the world in the last
decade, and many researchers have shown an increase in the frequency and size of floods
and droughts. In many countries in the world, various research has been actively conducted
to evaluate the impact of climate change on water resources systems. Christensen et al.
(2004) evaluated the impacts of climate change on water resources in the Colorado River
basin. Meanwhile, according to (Negash, et al., 2012) from the results of simulations using
climate change scenarios showed only a slight little change in surface runoff, the same is
conveyed (Ahmad, et al., 2011) that the monthly streamflow on average approximately the
same during the second period of the simulation results of the future. Future climate
scenarios typically result in a decrease in mean river flows and greater variability, but the
effect on the availability of water is not the same and varies in different regions of the river
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2. Willem Sidharno, Ali Masduqi, Umboro Lasminto
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
basin and water users (Ralph, et al., 2005). There is evidence that long-term climate change
has changed the flow pattern of the river, especially during the spring and summer, and
forecasts indicate these changes will continue and will affect the ability of the water supply
system to meet the needs of the future given the changes (Lee, et al., 2011).
Climatic conditions in the city of Kupang has low rainfall and high temperatures. This causes
Kupang city became one of the frequent water crisis. The purpose of this study is to see the
impact of climate change on water availability in the city of Kupang with models of climate
change SRES scenarios A1FI and B1 models combined with a demand for clean water
needs of the population with a low rate (150 lt/sec), medium (175 lt/ sec) and high (200
lt/sec) since the year 2012 to 2099 on the hydrological conditions. According to each
scenario, the results of the analysis will be used as input data to analyze the need and the
availability of water for the city of Kupang predict the amount of water in the future for each
scenario..
2. Methodology
Climate parameters such as temperature and precipitation is expected to change in the
future and could significantly affect the water resources available (Anil, et al., 2012).
Assuming that changes in precipitation and temperature hydrologic impacts of climate
change, and as the temperature and precipitation ranges in the same area as the range
expected in any scenario of climate change, only the temperature and precipitation changes
on climate change is needed (Melissa, et al., 1999). To determine the changes in the climatic
elements such as temperature and rainfall. Temperature and precipitation are two important
factors that influence the hydrologic processes meteorologic (Li li, et al., 2008). The results
have shown that long-term annual runoff volume on average decreased by using the A2
emissions scenario (Parrisa Sadat et al., 2013). Water resources is a major component of
the natural systems that might be affected by climate change (Bou-Zeid and Fadel, 2002).
This study uses two different scenarios based on models of the IPCC (Intergoverment Panel
of Climate Change). This model was chosen because it has the data of the variables that will
be examined in this study. The scenario used in this study is the scenario A1FI and B1 are
taken from the SRES (Special Report on Emission Scenarios) issued by the IPCC. Each of
these scenarios has a change of emphasis and socioeconomic scenarios different.
Climate Changes Projection
In this study will be used A1FI scenario that describes a future world with rapid economic
growth, low population growth rate, and the incentives for excessive fossil fuel technologies.
and the B1 scenario describes a convergent world, with a population growth similar to A1,
but with a significant change in economic growth in the field of services and information.
climate change is used to model the changes, which will affect the temperature and
precipitation changes in the world in the future. The scenario used in this study were taken
from the SRES (Special Report on Emissions Scenarios, 2000) issued by the IPCC are
shown in Table 1.
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3. The 4th International Seminar Department of Environmental Engineering
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Table 1. projected changes in temperature and precipitation scenarios SRES A1FI (highest
emissions in the future) and B1 ( lowest emissions in the future), divided into three sections
of time; 2013-2039; 2040-2069; 2070-2099.
Month
2010-1039 2040-2069 2070-2099
Temperature °C Precipitation % Temperature °C Precipitation % Temperature °C Precipitation %
A1FI B1 A1FI B1 A1FI B1 A1FI B1 A1FI B1 A1FI B1
DJF 0,86 0,72 -1 1 2,25 1,32 2 4 3,92 2,02 6 4
MAM 0,92 0,8 0 0 2,32 1,34 3 3 3,83 2,04 12 5
JJA 0,83 0,74 -1 0 2,13 1,3 0 1 3,61 1,87 7 1
SON 0,85 0,75 -2 0 1,32 1,32 -1 1 3,72 1,9 7 2
Source : (IPCC, 2007)
Hydrologycal Modeling
Hydrological impacts of climate change were evaluated with lumped hydrological model and
analyzed in accordance with the characteristics of the spring flood and the average inflow. In
general (Marie, et al., 2010). The variables used as reference calculations hydrology, water
availability is a surplus of water and storage volume. Hirologi variable calculation is based on
water balance models FJ Mock. To calculate the surplus water, required amount of daily
evapotranspiration, so in this paper the calculation of evapotranspiration calculated by the
Penman-Monteith equation. Model F.J. Mock deliberately used because it is considered
suitable to the climatic conditions and environmental Indonesia (FAO, 1973). While the
storage volume is calculated based on surplus water infiltration and assumptions which may
occur.
WS = CH – Eto (1)
V = 1/2(K+1)I + K x Vn-1 (2)
(3)
Where: WS: water surplus ; V: volume storage ; K: constant CH type of soil runoff: rainfall
(mm) ; Eto: evapotranspiration (mm / day) ; Rn: net radiation (MJ m-2 day-1) ; G: soil heat
flux density (MJ m-2 day-1) ; T: average daily temperature (oC) ; u2: wind speed at 2 m
height (m s-1) es: saturation vapor pressure (kPa) ; ea: actual vapor pressure (kPa) ; Δ:
slope vapor pressure curve (kPa oC-1) ; γ: psychometric constant (kPa oC-1)
Demographic data is one of the most important factors in the process of preparing a plan,
remember that every plan needs water intended for the benefit of themselves. Increasing the
number of residents in geometry method from the year 2012 with a population of 658 346
thousand, up to the year 2099 with a population growth of 3.19%.
3. Result and Discussion
Before performing the analysis, first performed calibration between runoff and rainfall that
occurred in the watershed in the city of Kupang and surrounding areas, so that the results of
the analysis are expected to be like the real situation. From the calibration results indicated
631

4. Willem Sidharno, Ali Masduqi, Umboro Lasminto
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
that the value of R is 0.9339, so that the calibration is acceptable. for rainfall and flow
calibration results can be seen in the watershed figure 1 and figure 2.
Figure 1. Results of the calibration graphs rain and runoff
Figure 2. Graphs of the rain and runoff that has occurred
From the results of the data analysis carried out by the rain and temperatures in the city of
Kupang since 1993-2012 using A1FI and B1 scenarios, then an increase in temperature
since the year 2013 to 2099 with a maximum temperature occurred on the A1FI scenario in
the year 2099 with an average temperature of 30.62 o
C and the lowest temperature is at the
mean temperature of the beginning before the simulation is 26.85 o
C. For more details can
be seen in Figure 3 and figure 4.
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5. The 4th International Seminar Department of Environmental Engineering
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Figure 3. Mean temperature change scenarios A1FI and B1
Figure 4. Monthly temperature chart and change
Of the temperature changes that occur using A1FI and B1 scenarios, it leads to changes in
the average evapotranspiration of truth conditions with scenario B1 in June, representing a
reduction of 4.8 mm / month to 2.94 mm / month. for more details can be seen in Figure 5.
633

6. Willem Sidharno, Ali Masduqi, Umboro Lasminto
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Figure 5. The average change in Evapotranpiration
From the analysis of rainfall using A1FI and B1 scenarios, then produce changes in average
rainfall that has increased since the year 2039 until the year 2099 with maximum average
rainfall in the A1FI scenario occurred in the year 2099 is 151.93 mm average rainfall, an
increase of 8, 09%. Minimum average rainfall also occurred on the A1FI scenario of 138.64
mm of rain or the normal decline of 1%. While the B1 scenario experienced a constant
increase since the year 2013 to 2099. For more details can be seen in Figure 6 and Figure 7.
Figure 6. Changes in average rainfall
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7. The 4th International Seminar Department of Environmental Engineering
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Figure 7. Average monthly rainfall
From A1FI and B1 scenarios are used, changes in runoff calculation method fjmock. showed
that a decline in runoff in B1 scenario by 23.20% and an increase of 1.23% in A1FI scenario.
To more clearly seen in the figure 8. And to effect changes in the runoff discharge 80% and
90%, showing not so big changes. However, by using scenarios of water demand levels low,
medium and high, then there is a shortage of water in April-October with the peak of the
water shortage occurred in 2070-2099 in reaching -49.73 m3/sec in normal climatic
conditions and maximum availability of water 2013-2039 was the year that is 606.95 m3/sec
in the B1 scenario. For more details can be seen in Figure 9a, 9b and drawing pictures 9c,
for each scenario water demand and climate change effects.
Figure 8. Graphic changes in runoff scenario A1FI and B1
635

8. Willem Sidharno, Ali Masduqi, Umboro Lasminto
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
Figure 9a. the average change in rainfall, discharge and water demand
Figure 9b. the average change in rainfall, discharge and water demand
Figure 9c The average change in rainfall, discharge and water demand
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9. The 4th International Seminar Department of Environmental Engineering
Proceeding ISEE 2013
ISBN 978-602-95595-6-9
4. Conclusion
From the results of the analysis, can be in the know that the effects of changes in
temperature and rainfall effect on increasing evapotranspiration. The more the temperature
rises then evapotranspiration ride. While the rainfall showed that promote increased rainfall
runoff and discharge the year higher. So also with the increasing population and the need for
increased water shortages caused high water in april to october. the general impact of
climate change did not affect the availability of water, but with the increase in population and
water demand increases, greatly affects the availability of water in Kupang city.
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Proceeding ISEE 2013
ISBN 978-602-95595-6-9
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