GIS-Based and computer simulation evaluation on . campus master plan
N. H. Wong , S. K. Jusuf
National University of Singapore, Singapore
In year 2005, National University of Singapore (NUS) released NUS Master Plan 2005, figure 2, as a response to the growing demand of the University development. As part of the implementation, NUS opened up land to build new buildings. It transformed the land use from green spaces into building. The greenery area is re-duced and it is expected that the ambient temperature of surrounding the area will rise. To maintain the eco-logical balance, the greenery area should be replaced or relocated at that place. This study is to provide in depth analysis the environmental changes in terms of greenery condition as one of the indicators and provide alternative scenarios to maintain it.
Figure 1. NUS Current Site Plan
Figure 2. NUS New Master Plan 2005
In this paper, an evaluation on NUS Master Plan 2005 will be discussed, providing the quantified data on its ABSTRACT
In the previous study, it was found that urban heat island intensity in National University of Singapore (NUS) cam-pus as high as 4oC at around 13:00. It is also concluded
that the presence of dense greenery in NUS environment is very important in keeping low ambient temperature. National University of Singapore has announced its new master plan in 2005, entitled NUS Master Plan 2005. Many new buildings will be built and in some areas ex-isting greenery will be removed. Geographical Informa-tion System (GIS) was use to evaluate the greenery con-dition. It was found that the greenery rate of NUS Master Plan 2005 will drop by about 3% from 55.10% of NUS current condition to 52.31%. In order to have a sustain-able environment, the greenery condition should be at least maintain at the same rate or even make it better. For this purpose, potential of increasing greenery area by rooftop greenery application was also done. The tar-get is to maintain the green rate of different zones at the same rate with current condition. In total, there will be more than 56% new buildings in NUS Master Plan 2005. Therefore, there is a good opportunity to plan and introduce the rooftop greenery or vertical greenery since in the early design stage
The ENVI-Met simulation predicts that the ambient temperature in NUS environment will increase about 1oC when NUS Master Plan 2005 is completed. It is due
to the reduction of greenery rate.
Keywords: GIS, Envi-MET simulation, master plan evaluation, temperature prediction, NUS Campus. 1. INTRODUCTION
This paper is one of the paper series presented in this PALENC 2007 Conference by the authors.
Temperature in urban area is increasing every year. Var-ious studies on the intensity of the Urban Heat Island have been done for many cities (Chandler 1965), (Lyall 1977), (Barring, Mattson et al. 1985), (Eliasson 1996), (Swaid and Hoffman 1990).
Based on the Urban Heat Island research in Singapore by the author (Wong 2004), in 20 years, the temperature in urban area has increased 1 ºC and in the long term minimum temperatures differences between urban-ru-ral, ranging from 0.3 to 1.9ºC.
urban elements (building, pavement and greenery). Comparison with the NUS current condition greenery will also be provided, including some suggestions to improve its greenery condition, including rooftop green-ery. Temperature prediction simulation was also done to compare the temperature condition between NUS current site plan and NUS Master Plan 2005. Thermal performance of planting more greenery on NUS Master Plan 2005 was also simulated.
2. METHODOLOGY
The main analysis tool for this study is Geographical Information System (GIS). Many researches make use of GIS as their analysis tool; especially in relation with Geographical data (Koster 1998), (Katzchner, Bosch et al. 2004), (Ao and Ngo 2000).
a. Quantifying greenery area of NUS Master Plan 2005.
NUS Master Plan 2005 was divided into 11 zones, based on the roads as the boundary of the each zone, as listed below:
1. Zone 1 : University Cultural Centre (UCC) and Of-fice of Estate & Development (OED)
2. Zone 2 : Sport & Recreation Centre (SRC)
3. Zone 3 : School of Design and Environment (SDE) and Faculty of Engineering
4. Zone 4 : University Hall (UH) and Yusof Ishak House (YIH) 5. Zone 5 : Faculty of Science
6. Zone 6 : Faculty of Art & Social Science (FASS) and Faculty of Law
7. Zone 7: King Edward VII (KE7), Institute of Mate-rials Research and engineering (IMRE) and Singapore Synchrotron Light Source (SLSS)
8. Zone 8 : Eusoff Hall and Temasek Hall
9. Zone 9 : Kent ridge Hall (KRH) and Shears Hall (SH) 10. Zone 10: Institute for Infocomm Research (I2R) 11. Zone 11: Prince George’s Park (PGP)
This zoning division was done to follow the same zon-ing classification which has been done for the NUS current site plan in order to compare the building-pave-ment-greenery area of the two plans.
In GIS, the NUS Master Plan 2005 was extracted the greenery area, building area and pavement area. Shape-files for these three areas were made in accordance with the data provided by Office Estate and Development (OED) NUS. The building area was calculated based on 2D plan area. Meanwhile, the 3D shapefiles for green-ery and pavement areas were generated and calculated.
b. Evaluation on NUS Master Plan 2005
In order to evaluate the NUS Master Plan 2005, com-parison with NUS current condition was made in terms of its urban elements (building-pavement-greenery ra-tio). Especially for the greenery condition, the changes of green rate were identified in each zone.
c. Temperature prediction on NUS Master Plan 2005
ENVI-met simulation was used to predict the ambient temperature. The simulations were conducted as follows: The whole NUS complex, with two different scenarios: NUS Master Plan 2005 (as designed) and NUS Master Plan 2005 with increased trees, see figure 3. The results of these two scenarios were also compared with the cur-rent condition ENVI-met simulation result.
Figure 3. The whole NUS complex - Two scenarios in ENVI-met simulation
Basic settings were employed in these simulations, as follows:
1. Temperature: 303 K.Temperature: 303 K.
2. Wind speed (at 10 m above ground): 1.6 m/sWind speed (at 10 m above ground): 1.6 m/s 3. Wind direction: South to NorthWind direction: South to North
4. RH: 84%RH: 84%
5. Roughness length in 10m: 0.1Roughness length in 10m: 0.1 6. Total simulation: 24 hoursTotal simulation: 24 hours 3. RESULTS AND DISCUSSIONS
a. Quantifying greenery area of NUS Master Plan 2005 Figure 4. shows the 11 zones of greenery division in NUS Master Plan 2005. It can be seen there are major changes and developments in zone 1 (UCC & OED), zone 2 (SRC), zone 3 (SDE & Engineering), zone 4 (UH & YIH), zone 5 (Faculty of Science), zone 6 (FASS & Law), zone 8 (Eusoff & Temasek Hall).
Figure 5. Building – Pavement - Greenery Area
The calculated result in figure 5 shows the large green area exists along the Kent Ridge Road in zone 7 over than 173,000 m2, followed by zone 4, close to 95,000m2.
The ratio and proportion percentage are calculated in table 1 and figure 6 to give a clearer picture for the com-position between the three elements building, pavement and greenery in each zone. It shows that zone 10 – I2R has the largest greenery proportion, 1 m2 building equals
to 9.8 m2 of greenery, followed by zone 7 – KE7, IMRE
& SSLS, 1 m2 building equals to 6.9 m2 of greenery.
For the building area proportion, zone 3 – SDE & Engi-neering has the largest building proportion, followed by zone 9, KRH & SH.
Figure 6. Proportion of building – pavement – greenery area Table 1. Building – pavement – greenery area and ratio of NUS Master Plan 2005
Green rate of NUS Master Plan 2005 was also calcu-lated to find which area has the largest area of greenery contributed totally to NUS Campus. It can be seen from the table 2 and figure 7, zone 7 – KE7, IMRE and SSLS contributes 11.62% of greenery from the total greenery area followed by zone 6, FASS & Law of 6.47%. This green rate value will be more useful after the compari-son with the NUS current condition in the next section.
Figure 7. Green rate of NUS Master Plan 2005
Table 2. Building – pavement – greenery area and ratio of NUS Master Plan 2005
b. Evaluation on NUS Master Plan 2005 – compari-son with NUS current condition
Comparison of building – pavement – greenery percent-age between current condition and NUS Master Plan 2005 was made to find the significant changes in terms of reduction in greenery area. The results are shown in table 8 and figure 8.
Table 8. Comparison of building – pavement – greenery percent-age between current condition and NUS Master Plan 2005
Figure 8. Comparison of building – pavement – greenery per-centage between current condition and NUS Master Plan 2005 From the table, it can be seen that the most significant reduction in greenery is at zone 4 (UH & YIH) from 80.8 % to 59%. There are also reductions of greenery area in some zones, such as in Zone 1 (UCC & OED) from 41.77% to 36.87%, zone 2 (SRC) from 57.25% to 55.3% and zone 3 (SDE & Engineering) from 43.27% to 36.13%. These reductions are mainly due to building developments in those areas.
In contrary, some areas increases their greenery area, such as in zone 7 (KE7, IMRE and SSLS) from 73.03% to 77.62%. This is mainly due to demolishing some small houses and reduction the area of King Edward VII Hall (KE7). In zone 9 (KRH & SH) and zone 11 (PGP) also increases the greenery area from 10.41% to 33.83% and from 37.37% to 48.84% respectively. It is mainly because the reduction of pavement area, con-verting the hard pavement area between building with grass and plants. It is a good practice which can be adopted for the other zones for example in zone 3 (SDE & Engineering) where pavements are built between the buildings canyon.
Table 9. Comparison of green rate between current condition and NUS Master Plan 2005
Figure 9. Comparison of green rate between current condition and NUS Master Plan 2005
The green rate between current condition and NUS Master Plan 2005 were also compared. The result can be seen in the table 9 and figure 9. It is similar with the pre-vious analysis that in some zones there are reduction in green rate due to the new buildings developments, such as in zone 1, zone 2, zone 3, zone 4zone 8 and zone 10. In total, the green rate is reduced from 55.1% to 52.31 %. From the environment sustainability point of view, it is not good to have this reduction. Therefore, plan-ning should be made to improve the greenery condition.
c. Temperature prediction on NUS Master Plan 2005
In the first analysis, the ENVI-Met simulation results of NUS Master Plan 2005-as designed and NUS Master Plan 2005-increased trees were compared with the re-sult of current condition. The graphical data of three dif-ferent scenarios were processed to be in the same range to get a fair comparison.
Figure 10. Comparison of ENVI-Met results with current condi-tions – Day Time
Figure 11. Comparison of ENVI-Met results with current condi-tions – Night Time
Figure 10 shows the day time ambient temperature com-parison. It is clearly seen that the ambient temperature of NUS Master Plan 2005 is much higher than the cur-rent condition. The difference is about 1oC. This is due
to the reduction of greenery area. It is the same as for the night time ambient temperature in figure 11. Even the dense greenery area along Kent Ridge Road has more significant impact, but the ambient temperatures around the buildings remain high, the urban heat island phenomena happens.
Putting more trees for NUS Master Plan 2005 during day time, figure 10, as compared with current condi-tion is still higher. Even more yellowish color starts to appear around the building. The impact of the increase of greenery is very significant during the night time, as in figure 11. The condition is better as compared with the current condition. Green and blue colors appear between the buildings as the result of a lower ambient temperature due to the presence of greenery.
It can be concluded that the presence of greenery is one of the methods to make the NUS Master Plan 2005 better. A more significant amount of greenery should be added. In addition to the previous analysis, the comparison only between the NUS Master Plan 2005-as designed and NUS Master Plan 2005-increased trees was made. To get a more detail comparison, some color scale ad-justments were made.
Figure 12 and 13 show that greenery really makes the ambient temperature cooler. The “hot spots” which initially occur near Faculty of Engineering, Universi-ty Cultural Centre and sport centre have now become much cooler as a result of cooling effects of much denser greenery in centre region of NUS and other areas. It can
be derived also the knowledge that planting greenery distributed around the complex has more impact rather than only concentrated in a particular area.
Figure 12. Comparison between NUS Master Plan as designed with increased trees – day time
Figure 13. Comparison between NUS Master Plan as designed with increased trees – night time
3. CONCLUSIONS
The building – pavement – greenery proportion was quantified for the NUS Master Plan 2005. There are ma-jor developments found in zone 1 (UCC & OED), zone 2 (SRC), zone 3 (SDE & Engineering), zone 4 (UH & YIH), zone 5 (Faculty of Science), zone 6 (FASS & Law), zone 8 (Eusoff & Temasek Hall). The green rate of NUS Master Plan 2005 is 52.31% reduced from 55.1%. The ENVI-Met simulation predicts that the ambient temperature in NUS environment will increase about 1oC when NUS Master Plan 2005 is completed. It is due
to the reduction of greenery rate from 55.1% in the cur-rent condition to 52.31%. The bare pavements between buildings without any greenery also contribute to the increase of ambient temperature.
Planting grass can prevent heat enters the building. A greater impact can be given by planting trees on the rooftop, because it gives the cooling effect due to eva-potranspiration process. Planting more trees at the hu-man occupancy level will give more benefits in reduc-ing the ambient temperature.
ACKNOLEDGEMENT
This research is supported by Department of Building, National University of Singapore. I would like to send
my great appreciation to Office of Estate and Develop-ment, especially for Ms. Lina Goh and Mdm. Helen Yip in providing all of the supporting data.
ABBREVIATIONS
FASS : Faculty of Art & Social Science
GIS : Geographical Information System
IMRE : Institute of Materials Research and engineer-ing
I2R : Institute for Infocomm Research KE7 : King Edward VII
KRH : Kent ridge Hall LT : Lecture Theater
NUS : National University of Singapore OED : Office of Estate and Develop�ent
PGP : Prince George’s Park UCC : University Cultural Centre UH : University Hall
SDE : School of Design and Environment SH : Shears Hall
SLSS : Singapore Synchrotron Light Source SRC : Sport & Recreation Centre
YIH : Yusof Ishak House REFERENCES
Ao, K. F. and H. T. M. Ngo. (2000). “G�S Analysis of Vancouver’s Urban Heat Island.” 2006, from
http://www.geog.ubc.ca/cours-es/klink/g470/class00/kfao/abstract.html.
Barring, L., J. O. Mattson, et al. (1985). “Canyon Geo�etry, Street Temperatures and Urban Heat Island in Malmo, Sweden.” Journal of Climatology 5: 433-444.
Chandler, T. J. (1965). “City Growth and Urban Cli�ates.” Weather 19: 170-171.
Eliasson, �. (1996). “Urban Nocturnal te�peratures, street geo�-etry and land use.” Atmospheric Environment 30(3): 379-392. Katzchner, L., U. Bosch, et al., Eds. (2004). Thermal comfort mapping and zoning. Designing open spaces in the urban envi-ronment: a bioclimatic approach, Centre for Energy Renewable Resources.
Koster, E. (1998). “Urban �orphology and co�puters.” Urban Morphology 2(1): 3-7.
Lyall, �. T. (1977). “The London Heat –�sland in June – July 1976.” Weather 32(8): 296-302.
Ong, B. L. (2003). “Green plot ratio: an ecological �easure for architecture and urban planning.” Landscape and Urban Plan-ning 63: 197–211.
Swaid, H. and M. E. Hoff�an (1990). “Cli�atic ��pacts of Ur-ban Design Features for Highand Mid-latitude Cities.” Energy and Buildings 14: 325 - 336.
Wong, N. H. (2004). Study of urban heat island in Singapore. Singapore, National University of Singapore: 240.
