Development density incentives

Bangkokians were not certain that flooding could be avoided as, after September’s heavy rains, it almost seemed inevitable there would be inundation. 

Why does this keep happening? Is it a result of climate change or is it simply an outcome of poor maintenance of city sewers? Can it be attributed back to an urban plan established almost two centuries ago? Whatever the cause, blame is not the way out. We have to fix this.

We have completely transformed Bangkok’s landscape. The Chao Phraya River delta’s low-lying alluvial soil and mangrove forests are now concrete plains occupied by mega-structures blocking hydrological flows. 

Bangkok provides only 3 square metres of green area per capita, among the least in Asia (source: The Economist Intelligence Unit). The World Health Organisation has recommended that big cities should maintain at least 10 square metres of green area per capita to ensure residents’ good health.

How do we find the additional 7 square metres of green area in order to meet these guidelines, as well as mitigate the effects of annual flooding?

We may have a chance. The latest Bangkok Metropolitan Authority (BMA) city planning code has a game-changing mandatory requirement. From now on, new commercial development will need to accommodate more open space. 

Fifty per cent of that open space must be green and built with pervious surfaces through which rainwater can penetrate. The area must be planted, although the code does not currently allow siting on roofs. 

Investor-owners of high-value plots will be most affected because their buildable area will be lessened.

Critics argue that this new land-use regulation would restrict growth in the city centre, lead to sprawl in Bangkok’s outskirts, and contribute to the destruction of green areas surrounding the metropolitan core.

In anticipation of such criticism, the new planning code provides solutions for investors seeking to maximise buildable area in the form of ‘development density incentives’ or ‘floor area ratio’ (FAR) bonuses.

If a project is designed and constructed in compliance with Thai green building standards, it will be eligible for an increase in buildable space relative to the area of the land upon which the building is sited. This can be negotiated on a floor-by-floor basis to permit buildings to cover more of the site at ground level, and step back from the street at higher levels, for example. 

Since the regulation was promulgated last year, the Thai Green Building Institute (TGBI) has worked with the BMA’s City Planning Department to develop an assessment tool for green buildings.

A set of green building design guidelines – Thailand’s Rating for Energy & Environmental Sustainability for Pre-New Construction (TREES Pre NC) – is now ready to be used for this purpose. Besides the potential to influence greater provision of green space, these guidelines may be a powerful game-changer to ramp up green building in Thailand.

TREES Pre NC is a point-based rating tool, with 62 achievable points. A development designed to achieve at least 22 points will be awarded at the First level, or 5-per-cent FAR bonus. The Second level, with 10-per-cent FAR bonus, needs 28 points. The Third level with 15-per-cent FAR bonus requires 33 points and the Fourth level with 20-per-cent FAR bonus needs 45 points. 

There are seven assessment categories in TREES Pre NC – Building Management, Site and Landscape, Water Conservation, Energy and Atmosphere, Indoor Environmental Quality, Environmental Protection, and Green Design Innovation.

A building owner must contact the TGBI to apply for TREES Pre NC and submit design drawings and calculation sheets to the body, among other things. If approved, the building owner brings the approval letter from the institute to apply for the FAR Bonus and to request building permission.

During construction, the TGBI will visit the construction site regularly to check for compliance. Failure to adhere to the approved design will result in revocation of building permissions and discontinuation of construction by BMA order.

This mechanism has been used extensively in other cities to promote environmentally sensitive development. Although the greenest decision of all is to refrain from building, or to build less, as long as a building agenda is pursued, why not build greener and better if the options are available?

 

Atch Sreshthaputra is Assistant Prof, Department of Architecture, Faculty of Architecture, Chulalongkorn University and committee member and founder of the Thai Green Building Foundation.