Floods and raising the city Tri Harso Karyono  ;   Professor of architecture at Tanri Abeng University (TAU),  Author of Green Architecture (2nd edition, 2014)

JAKARTA POST, 05 April 2014

                                      

                                                                                         

                                                             

Recent news reports stated that the Dutch were ready to help find a solution to Jakarta’s severe annual flooding. Coastal development is being considered to prevent the capital from being inundated by seawater. Due to global warming, millions of people worldwide who live in coastal cities like Jakarta will face increasingly serious floods as sea levels rise due to melting polar ice. Global warming, in which the average earth temperature rises, is caused by excessive greenhouse gas (GHG) emissions. Buildings account for around 15 percent, while transportation and industry contributed 14 percent and 21 percent, respectively, and the remainder was emitted by other activities. The 1997 Kyoto Protocol suggested that a number of industrial countries should reduce their carbon emissions by 5 percent from 1990 levels by 2008 through 2012. Levels were evaluated in 2012 to determine the impact of the Kyoto Protocol on reducing global carbon emissions. The evaluation found that some developed countries, like the UK, France and Germany and most of those in Eastern Europe, had successfully reduced their emissions — and by more than the targeted figure; while other industrialized countries, like Canada, Australia and Japan, had failed to reach the mandated goals. Despite the efforts, global carbon emissions are continuing to increase, reaching 34 billion tons recently, and threatening a rise in global temperatures of up to 7 degrees Celsius by 2100. In her 2009 book, Adapting Buildings and Cities for Climate Change, Sue Roaf of Heriot-Watt University in Edinburgh, Scotland, stated that sea levels had risen at a rate of 0.1-0.2 millimeters per year over the past 3,000 years, but that in the 20th century alone, this had increased to 1-2 mm per year, or about 10 times faster than previously, due to global warming. This phenomenon creates heavy flooding, particularly in coastal areas, which means that cities like Jakarta would become flooded even in the absence of rain, as rising seawater encroached onto the land. Jakarta has seen massive development with the construction of an increasing number of buildings and roads, creating more land surfaces covered with hard materials. Since the city has no integrated drainage system to accommodate rainwater runoff, it is becoming ever more vulnerable to flooding and increasing the urgency to find a solution. Our forefathers managed their immediate environment wisely. In a number of vernacular societies, people built houses on stilts to protect themselves from would-be invaders, as well as wild animals such as tigers. Stilt houses also provide good protection against flooding as the ground surface beneath the house is open and uncovered, allowing it to absorb rainwater and other inundations. If we want to create a sustainable city, namely a city that experiences less-frequent flooding or even no floods at all, we should emulate our forefathers. The book, Time To Eat The Dog: The Real Guide To Sustainable Living (2009), states that the human race could survive on the planet’s natural resources if we all lived in the same way, namely in a way akin to our great-great-grandparents over 100 years ago. A city could be built on stilts, in which its multistory buildings and roads would be elevated, leaving the ground surface open. The open ground surface beneath a building’s ground floor would be laid with water-absorbing materials like concrete blocks, to enable the speedy absorption of rainwater. The space would not be allocated for any permanent structures, other than vertical structures such as stairs, escalators and elevators. No basements would be allowed; any that were already built would be used as water tanks to accommodate runoff. The opened ground floor of the building would not only enable the absorption of excessive rainwater, it would also provide space to accommodate excessive rainwater in case of flooding. If this idea was applied to 60 percent of existing high-rises and 100 percent of new buildings, the area of uncovered ground surface in Jakarta would significantly increase, which would substantially reduce the amount of runoff. By having many multistory buildings with open ground floors, air movement around the city would be accelerated, creating a cooling effect amid Jakarta’s tropical climate. Furthermore, in the very near future, we should stop enclosing the land around buildings. Outdoor spaces surrounding buildings in the city should be considered public space that can be used by everyone. This would help to create shortcut access routes, encouraging more people to move around the city on foot and by cycling around and beneath these buildings. Main roads, which would cater to motorized vehicles, would be elevated, while beneath them, there would be smaller arterial roads, pathways and gardens for cyclists and pedestrians. Divisions would be made between non-motorized and motorized vehicles when entering the building. Pedestrians and cyclists would enter the building from the ground floor, while people on motorized vehicles, mainly public transportation like the monorail, would enter the building at the lobbies on the second or third floors, which would be at the same level as the elevated roads. The question is how can we put these ideas into practice? How can we remove the ground floors of many existing buildings in Jakarta in order to make them rainwater absorbent? How can we transform basements from what are mainly car parking areas into rainwater tanks to prevent flooding? The Jakarta administration could issue a decree to oblige building owners in flood-prone areas to transform their buildings. This process could be carried out in stages to avoid the disruption of activities inside the buildings. The local authority could also construct the elevated roads and flyovers in a gradual process. If all these measures were implemented, they would go a long way toward facing global warming and mitigating its threats, and they would also help Jakarta reduce its annual flood risk. ●

Frequent cases of flooding reduces Jakarta to third-world city

Frequent cases of flooding reduces Jakarta to third-world city Tri Harso Karyono ;   A Professor of Architecture and Author of “Green Architecture: An Introduction to the Knowledge of Green Architecture in Indonesia”

JAKARTA POST, 09 Februari 2013

The recent flooding in Jakarta should not have had such a severe impact had the city’s authorities anticipated the disaster, which occurs annually during rainy season. There are three main aspects associated with the cause of flooding in Jakarta: Global, regional and local. In the global aspect, Jakarta and all coastal cities in the world face a high potential of flooding due to global warming.  Girardet and Mendonca state in their book, A World Renewable Energy, Ecology, Equality (2009), that about 600 million people worldwide living on small islands and in coastal cities, such as Jakarta, are faced with a serious threat of flooding as the sea level continues to rise due to the melting of polar ice flows due to global warming.  From the regional point of view, Jakarta’s flooding resulted from large amounts of water from upstream rivers in West Java that flowed across the capital.  Deforestation in the headwater regions because of development of farms, plantations and housing has reduced rainwater absorption, sparking massive water flows to lower areas and, hence, the flooding in Jakarta.  To avoid the floods, there is a plan to develop artificial lakes to act as water reservoirs along the West Java border outside Jakarta to take the brunt of the overflowing river. The West Java authority is only reluctantly providing land for this purpose.  In many developed countries, inland waterways, such as rivers, fall under the control of a central or regional agency, instead of the local government areas in which the rivers are located.  England and Wales have a number of so-called regional water authorities that manage things like water treatment and land drainage.  To deal with the overflow of rivers or lakes, these agencies do whatever they can to avoid serious flooding, such as constructing artificial lakes near rivers.  According to this concept, rivers are not possessed by local authorities, as they were in the past, but by different water authorities that answer to the central government. If a similar system was applied here, then the current dispute between Jakarta and West Java would be overcome by the agency. The third cause of Jakarta’s flooding is the local factor. Many urban experts argue that the lack of open spaces and green areas in Jakarta is a source of the floods, as rainwater cannot be absorbed by the ground surface.  Being an urban area, the city’s ground surfaces are primarily covered by hard materials in the form of buildings, roads, parking lots and other amenities.  However, the main purpose of greening the city is not to absorb rainwater, but rather to reduce its air temperature.  Increased vegetation would reduce the “hot urban-island effect” in the city. With lower air temperatures, a tropical city can reduce its energy consumption for cooling, and become a low-energy city. Other than fulfilling an aesthetic aspect, greening a city also helps to absorb carbon dioxide and dust. Plants need carbon dioxide to grow. Measures to “green the city” can be implemented anywhere.  They do not have to be at ground level only; green areas can also be established on rooftops and on a building’s walls and balconies with potted plants.  The main idea of greening is to minimize the amount of hard material being exposed to the sun, so that the penetration of solar radiation can be kept to minimum.  With heavy rainfall, it is not logical to expect rainwater in tropical cities like Jakarta to be absorbed by the ground surfaces. Countless cities in the world that are dominated by hard ground surfaces like concrete and asphalt remain free of flooding despite heavy rains. The rapid growth of Jakarta has eradicated many green spaces, seeing them replaced by buildings, parking lots and roads. Rainwater that falls on hard surfaces must be able to flow through water channels to lower destinations like canals or rivers, ultimately ending up flowing out to sea. This can be done systematically by means of an integrated drainage system.  Unfortunately, Jakarta does not have an integrated drainage system and even lacks appropriate water channels. Old channels, built in the 1960s are maintained to this day, although they are no longer sufficient to accommodate the current levels of rainwater.  Since the ground surfaces are almost entirely covered by concrete and asphalt, the runoff rainwater becomes 10 times greater than before and, consequently, inundates roads and paralyzing traffic. Constructing an integrated drainage system is the key to overcoming Jakarta’s floods. Although the entire surface of the city is covered by concrete and asphalt, the city will not be flooded if it is well equipped with an integrated drainage system.  All the runoff water would be circulated accordingly by the water channel and directed to the sea. The dimension of the channels is also an important consideration.  The water channels should be sufficiently large to accommodate the runoff water and so avoid overflowing water that causes flooding.  Beside an integrated drainage system and an increase in the size of water channels, there needs to be an ongoing program to dredge sediment from the city’s rivers, canals and lakes.  The ability of these urban waterways to contain runoff rainwater has markedly declined in recent years due to sedimentation.  Many high-rise, glass-box buildings have been erected in the capital, replacing a number of old buildings. Architects argue that the new architecture improves the city’s aesthetic look. Sadly, all the new buildings are devoid of historic interest which, in turn, makes the city a less attractive destination for tourists.  As a capital city, Jakarta requires tough calculations to build. A utilitarian grand plan is much more important than the aesthetics of the city.  Although Jakarta is adorned with tall buildings that presumably seem opulent to visitors and Indonesians from more remote regions, the frequent floods that have hit the city only strengthen the argument that the capital is little better than a third-world city; a city with no integrated utility system. ●