FLUSHING SEMARANG

Facing water merged into the city structure

The city of Semarang is dealing with mayor problems concerning climate change and population growth. In the hills the land is sliding due to unstable ground and deforestation. In the lower part the main issues are flooding by rivers after a heavy rainfall and flooding of the sea water. This all becomes more extreme in the future because the land is subsiding due to pumping water from the ground for industries and households. In the ‘water is leverage’ project these issues are dealt with. By focussing on these problems with four solutions; spongy mountain, rechannelling the city, feeding the industries and recharging the aquifers.

But solving these issues doesn’t bring any quality to the water and the life in the city. The city of Semarang contains so many waterways, from small ditches in the street to canalised rivers that move through the city. The quality is now unseen. The open water is used as a open sewage and trash way. You can compare it to Amsterdam 100 years ago. The beautiful canals as we see today, where back in the 19th century very dirty. By building a good sewage system and let the water move the canals where flushed clean.

Flushing Semarang

The concept of ‘Flushing Semarang’ is explained. This consist of two important areas that are needed to solve the problem of dirt water, heavy floods and land subsidence. In the higher/ greener part of the city large water basins are implemented along the river streams to keep as much water as possible. It is a controlled water system that stops the city from flooding and cleans it in a natural way by taking out the plastic that is thrown in from the mountains. When this clean water is entering the lower part of the city it is steered through a couple of canals/rivers. Instead of dumping all the dirt water to these rivers, we now use this clean water from the mountains to flush the city.

Polder system

This system works with three different types of streams; the main stream, the flush stream and the kampong stream. The main stream holds the clean water from the mountains and doesn’t get dirty from the streets anymore. The space around the water suddenly becomes attractive to live, cycle and walk along. A new recreation network is created where the city grows along. The flush stream functions to flush the city clean by pumping in the clean water and move it through the neighbourhoods. The kampong streams are connected to it and fill the flush stream with the grey water from the households. It is placed along existing roads and railways and focuses on movement. In the end of the flush stream the water becomes dirt grey water and holds a lot of garbage. It is cleaned by a combination of natural and mechanical filtering and flows back into the main stream. The whole systems functions on rainwater that is collected on the roofs and is used in the households. The grey and black water is separated.

The Kampong

The Semarang river becomes an important structure in the city again, where living and all the main functions are along. Housing is desified, comfortable routing is added and public space is brought into the city structure.

All of this is connected to the watersystem. The Semarang river is clean again and it becomes the best space to live along. The filter areas are special areas in the city structure. Here public functions such as schools, restaurants and Mosques are centered. These spaces are characterised by open space, trees, connection to water and a crossing.

Pasar Johar

This existing market hall (in the current situation not used space) is turned into an open green space combined with a floating market. The green space is the ending of two flush streams and funcions as a helofythen filter. On top of this the market is designed in a riget way with wide walkways to make it a comfortable space.

As in the filter square, the Semarang river bends in and forms a special element opening up towards the market. Pathways and materials are used to mark the public space and create routing.

Filter square

The filter square is an open space that marks the ending of a flush stream and the beginning of the route along the Main stream. Under - neath the square big septictanks are filtering the water. This shapes the square into an open space with trees around it to create shade. Here people can enter the public builings, hang around, eat and meet each other.

To transfer from scooter/car to bike a big parking ring is placed in the south east of the square, blocked by a big hedge. A bike system is added to get people cycling. The route along the river bends into the square, creating a stair for the people to get in touch with the clean water.