At this time the world’s major cities are faced with various problems. Starting from the degradation of environmental quality, uncertain climate, uncontrollable population growth, and mobility problems in the population itself. The impacts of existing problems can be floods caused by poor urban drainage systems, as well as congestion due to the poor transportation system and also exacerbated by a large number of residents who are reluctant to use mass transportation. The problems mentioned above also occur in the capital of the country that located in two continents, Istanbul. It is estimated that the congestion losses incurred in the city reach $ 2.8 Billion per year, which is worsened by the flood disaster that hit the city, causing a loss of $ 3.1 Billion per year. Thus, the Turkish Government initiated to create a Deep Tunnel to solve the problem.
The deep tunnel is a giant tunnel built 20-30 meters underground that serves to overcome various problems in the field of transportation, water, and also at the same time distributing the communication infrastructure of fiber optics. Deep tunnel offers advantages that are considered effective, ie the construction will not disrupt the activities of people who are above it. Utilization of deep tunnel in each country varies according to their needs, but the most common is to solve the problems of congestion and flooding.
Bosphorus Strait Deep Tunnel
Therefore, by 2015 the Istanbul City government announces it will build the Deep Tunnel mega project to be built just below the Bosporus Strait which is divided into 3 levels. Where the mega project 3 sub-sea tunnel level in Istanbul consists of 2 levels of motorway that will occupy the level 1 and 3, and 1 fast metro way which will be in level 2. This will make Deep Tunnel is the only 3 sub-level -sea tunnel in the world. The Mega project is expected to cost $ 3.5 billion.
3 Level Sub-Sea Tunnel
The project that began in October 2013 is considered to be able to integrate 9 different rail-based public transportation by presenting fast metro. Fast metro is expected to accommodate 6.5 million passengers per day. It will also allow for easier and faster connections to the ring road, thus connecting all major arterial roads that will facilitate passenger access to switch the transport mode.
The tunnel will be built along 5.4 km, with tunnel length across the sea along the 3.34 km. The presence of this tunnel can be a solution to a very severe Istanbul congestion by cutting time and distance. According to the Turkish government, 2 levels of available motorways can save travel time up to 70% of normal time. For example, travel time from Kazlıçeşme district on the European side to Göztepe district on the Asian side takes 100 minutes, but it is estimated that with this tunnel it takes only 15 minutes across the two areas.
The explanation above is enough to prove that the deep tunnel is quite effective to overcome the problem of traffic jams and floods in Turkey with excess advantages it offers. Jakarta can also apply this deep tunnel, the center of sustainable infrastructure development studies UI issued a study of deep tunnel innovation named Prasti. So it is not impossible to apply this deep tunnel to overcome the classical problems of the city of Jakarta, namely congestion, and flooding.