GIS-Based and computer simulation evaluation on. campus master plan

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1 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and 1121 GIS-Based and computer simulation evaluation on. campus master plan N. H. Wong, S. K. Jusuf National University of Singapore, Singapore ABSTRACT In the previous study, it was found that urban heat island intensity in National University of Singapore (NUS) campus as high as 4 o C 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 Many new buildings will be built and in some areas existing greenery will be removed. Geographical Information System (GIS) was use to evaluate the greenery condition. 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 sustainable 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 target 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 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 1 o C 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. 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 reduced and it is expected that the ambient temperature of surrounding the area will rise. To maintain the ecological 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 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. Various 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-rural, ranging from 0.3 to 1.9ºC. 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 PALENC Vol 2.indd /9/2007 1:26:13 µµ

2 1122 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and 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 greenery. Temperature prediction simulation was also done to compare the temperature condition between NUS current site plan and NUS Master Plan Thermal performance of planting more greenery on NUS Master Plan 2005 was also simulated. 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 current condition ENVI-met simulation result. 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 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 Office 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 Materials 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 zoning classification which has been done for the NUS current site plan in order to compare the building-pavement-greenery area of the two plans. In GIS, the NUS Master Plan 2005 was extracted the greenery area, building area and pavement area. Shapefiles 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 greenery and pavement areas were generated and calculated. b. Evaluation on NUS Master Plan 2005 In order to evaluate the NUS Master Plan 2005, comparison with NUS current condition was made in terms of its urban elements (building-pavement-greenery ratio). Especially for the greenery condition, the changes of green rate were identified in each zone. 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. 2. Wind speed (at 10 m above ground): 1.6 m/s 3. Wind direction: South to North 4. RH: 84% 5. Roughness length in 10m: Total 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 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 4. Greenery zoning of NUS Master Plan 2005 PALENC Vol 2.indd /9/2007 1:26:14 µµ

3 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and 1123 Green rate of NUS Master Plan 2005 was also calculated 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 comparison with the NUS current condition in the next section. 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 m 2, followed by zone 4, close to 95,000m 2. The ratio and proportion percentage are calculated in table 1 and figure 6 to give a clearer picture for the composition between the three elements building, pavement and greenery in each zone. It shows that zone 10 I2R has the largest greenery proportion, 1 m 2 building equals to 9.8 m 2 of greenery, followed by zone 7 KE7, IMRE & SSLS, 1 m 2 building equals to 6.9 m 2 of greenery. For the building area proportion, zone 3 SDE & Engineering has the largest building proportion, followed by zone 9, KRH & SH. Figure 7. Green rate of NUS Master Plan 2005 Table 2. Building pavement greenery area and ratio of NUS Master Plan 2005 Figure 6. Proportion of building pavement greenery area Table 1. Building pavement greenery area and ratio of NUS Master Plan 2005 b. Evaluation on NUS Master Plan 2005 comparison with NUS current condition Comparison of building pavement greenery percentage 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 percentage between current condition and NUS Master Plan 2005 PALENC Vol 2.indd /9/2007 1:26:14 µµ

4 1124 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Figure 8. Comparison of building pavement greenery percentage 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, converting 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 previous 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 %. From the environment sustainability point of view, it is not good to have this reduction. Therefore, planning 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 result of current condition. The graphical data of three different scenarios were processed to be in the same range to get a fair comparison. Figure 10. Comparison of ENVI-Met results with current conditions Day Time PALENC Vol 2.indd /9/2007 1:26:15 µµ

5 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and 1125 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 11. Comparison of ENVI-Met results with current conditions Night Time Figure 10 shows the day time ambient temperature comparison. It is clearly seen that the ambient temperature of NUS Master Plan 2005 is much higher than the current condition. The difference is about 1 o C. 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 condition 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 adjustments 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, University 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 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 There are major 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 1 o C when NUS Master Plan 2005 is completed. It is due to the reduction of greenery rate from 55.1% in the current 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 evapotranspiration process. Planting more trees at the human occupancy level will give more benefits in reducing the ambient temperature. ACKNOLEDGEMENT This research is supported by Department of Building, National University of Singapore. I would like to send PALENC Vol 2.indd /9/2007 1:26:15 µµ

6 1126 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and my great appreciation to Office of Estate and Development, 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 engineering I2R : Institute for Infocomm Research KE7 : King Edward VII KRH : Kent ridge Hall LT NUS OED PGP UCC UH SDE SH SLSS SRC YIH : Lecture Theater : National University of Singapore : Office of Estate and Development : Prince George s Park : University Cultural Centre : University Hall : School of Design and Environment : Shears Hall : Singapore Synchrotron Light Source : Sport & Recreation Centre : Yusof Ishak House REFERENCES Ao, K. F. and H. T. M. Ngo. (2000). GIS Analysis of Vancouver s Urban Heat Island. 2006, from Barring, L., J. O. Mattson, et al. (1985). Canyon Geometry, Street Temperatures and Urban Heat Island in Malmo, Sweden. Journal of Climatology 5: Chandler, T. J. (1965). City Growth and Urban Climates. Weather 19: Eliasson, I. (1996). Urban Nocturnal temperatures, street geometry and land use. Atmospheric Environment 30(3): Katzchner, L., U. Bosch, et al., Eds. (2004). Thermal comfort mapping and zoning. Designing open spaces in the urban environment: a bioclimatic approach, Centre for Energy Renewable Resources. Koster, E. (1998). Urban morphology and computers. Urban Morphology 2(1): 3-7. Lyall, I. T. (1977). The London Heat Island in June July Weather 32(8): Ong, B. L. (2003). Green plot ratio: an ecological measure for architecture and urban planning. Landscape and Urban Planning 63: Swaid, H. and M. E. Hoffman (1990). Climatic Impacts of Urban Design Features for Highand Mid-latitude Cities. Energy and Buildings 14: Wong, N. H. (2004). Study of urban heat island in Singapore. Singapore, National University of Singapore: 240. PALENC Vol 2.indd /9/2007 1:26:15 µµ