5.6 R OLE AND I NFLUENCE OF U RBAN P LANNING IN THE A CTUAL E VACUATION P LANNING AND V ULNERABILITY R EDUCTION . 114
5.6.1 Spatial Planning Orientations Related with Tsunami Exposure and Evacuation Infrastructures in 2010-2030
The City Development Planning Agency (BAPPEDA) of Padang has expended efforts on revising the city’s spatial plan. Based on conversations with the planning actors, the last spatial plan was developed for the period from 2004 to 2013 as manifested in the Regional Regulation 10/2005 (PERDA 10/2005) without consideration of tsunami and earthquake hazards. However, after the tsunami in 2004, the need to revisit the regional plan had arisen. In 2007, a new law on spatial planning (UU 26/2007) was passed that encompasses the necessity to develop spatial planning based on disaster mitigation in order to enhance security and welfare. Then, an identification of the problems and their evaluation was carried out and formulated in a Disaster Management Strategic Plan, which served as the first input for the revised spatial plan, as body of reference for the district regulation (PERDA), which will now be applied for a 20‐year period.
In the current Spatial Plan 2010‐2030, the aspects of earthquake and tsunami hazards have been taken into account. This Spatial Plan was also shaped by the reconstruction and rehabilitation process of the city after the major earthquake event on September 30, 2009. The concern to integrate disaster mitigation into this plan has been indicated clearly in the long‐term 2010‐2030 objective formulation:
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“To achieve that the city of Padang shall evolve as a metropolitan city based on disaster mitigation which is supported by the development of the trading, service, industrial, and tourism sectors.”
The formulation makes explicit the importance of disaster mitigation in contrast to the previous Spatial Plan 2004‐2013, which stated the objective as:
“To achieve structure and spatial use of the city as a modern and cultural coastal city”
The Spatial Plan defines tsunami prone areas firstly as areas with topographical slopes of 0‐2% from the coast that are most likely to be inundated. Furthermore, it adopted the classification of tsunami hazard levels based on the potential specific energy of a tsunami (composed of inundation depth and velocity), as proposed in the scope of the “Last‐Mile – Evacuation” (Taubenbửck et al. 2012) and reflected the discussions of the consensus meeting on tsunami hazard modelling results in 2010. The development of a tsunami hazard map was very locally driven using a different approach than the tsunami hazard classification suggested in the National Technical Guide of Public Work Regulations Permen PU 6/2009 (see Sub‐chapter 3.1) at least in two points. First, it only considers one most plausible source scenario, rather than multi‐scenario approach using probability (or return period) of tsunami occurrences of different magnitude. Second, it includes not only the potential inundation depth, but also the potential velocity represented by specific energy, thus taking into account the stability or manoeuvrability of the people (RESCDAM 2000) during evacuation.
The ideal approach to reduce tsunami risk had already been integrated in the new spatial plan, including the consideration of space for evacuation routes or shelters, the development of city sub‐
centres to reduce a too centralized concentration of population, seismic‐resistant building codes, and the provision of infrastructures taking into consideration emergency planning. One important city development orientation in the new spatial plan is the development of settlement areas towards the eastern part of the city further away from the coast, which have been primarily used for agricultural purposes, whereas the built areas along the coast should be focusing more on trade and service functions.
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Figure 5-31 Comparison of existing land use in 2007 and future land use orientation in 2010-2030
Source: Basis maps from BAPPEDA Padang 2010, own annotations Mostly highly densed
settlement mixed with most trade and services, government centers, esp.
along main roads and around central market
Agricultural use (rice fields)
Controlled densed settlement, oriented towards mainly trade
and services, city government centers
relocated, considering new development of subcenters in the east
and north
Cultural conservation area of the old town
Pondok Muaro
Oriented towards settlement areas with green open space
Existing land use map 2007 Spatial plan 2010-2030
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The Spatial Plan describes only orientations of spatial patterns and structures with regard to the development of various city functions and infrastructures. A detailed spatial plan and zoning regulation based on the Spatial Plan for the study area was not yet available at the time of the study period. Thus, it was not possible to assess the specific impacts on the components and needs identified in the previous Sub‐chapters (particularly 5.1, 5.2, 5.3). In this section, the Spatial Plan was only reviewed focusing on its orientation with regard to various components (the assessment table can be found in Annex). Specific aspects with reference to the needs identified in the previous section are still to be incorporated in the detailed plan.
Impact on dynamic exposure
The overall orientations in the Spatial Plan suggest overall a reduced exposure to tsunamis. Areas with high and very high risk of tsunamis are recommended as conservative areas or utilized as open green areas, cropping and agricultural areas. In the already built areas, which are the largest part of the exposed areas within the study, the spatial development intensity should be limited towards non‐settlement activities and not to centralized population concentration. The traffic pressure and population concentration in the current city centre should also be reduced due to the future development of settlement areas in the eastern and southern part of the city. It is planned to relocate some of the government offices to the northeast of the city (Air Pacah) and to develop further sub‐service centres in the north, south and east to support the current city centre in decentralizing the city activities.
However, the increasing role of the city as a metropolitan city and regional service centre that may attract more inmigrants and commuters, as well as the intensification of trading, services, and tourism activities in the areas with potential tsunami inundation risk – in spite of the limitation of settlement growth – may have a challenging impact on the exposure of the people during the day. In this case, there may be more working areas and working population exposed in the long‐term, as well as more people who do not live in the area but conduct activities there. Also, a punctual increase of exposure, e.g. due to more intensive tourism activities in Muaro and Padang Hill area is to be expected.
Impact on access to safe places
The access to safe places should be enhanced by means of improvement of the transportation network and evacuation shelters. The development is partly linked with the social and economic objectives, such as the improvement of informal trading areas, parking management, and the overall improvement of the road network. The intention to develop new roads perpendicular to the coastline and escape buildings was also mentioned, but no specified spatial allocations were formulated in this plan and the capacity of the current facilities as potential shelters would not be sufficient considering the amount of exposed people. Furthermore, there was no indication of specific protection measures referring to more intensive non‐settlement activities in the exposed areas.
118 Impact on access to warning
The Spatial Plan also provides a clear hint towards improvement of the access to warning by increasing the capacity of the current electricity supply and telecommunication infrastructure. It identifies various sources of power in case of emergencies, mentioning emergency as one criteria to be considered in the zoning regulation for wireless tranceiver towers.