Delta Life 7

DELTARES, MARCH 2017 27 The Taiwanese city of Kaohsiung is flooded regularly. The local government is now working on its metamorphosis into a sponge city , a city that uses every square metre to collect water. 'We are giving the land back to the river.' BY HARRIOT VONCKEN IMAGE ISTOCKPHOTO RESILIENT CITIES IN PRACTICE THE SPONGE CITY OF KAOHSIUNG W ith 2.7million inhabitants, Kaohsiung is Taiwan's second largest city. Last June, approximately 800 millimetres of rain fell in two days. That is the equivalent of a full year of rain in the Netherlands. After Typhoon Morakot killed 677 people in 2009 and Typhoon Fanapi flooded 680 hectares of land a year later, Kaohsiung decided to switch to a new approach. Li-Ming Hsu, alderman for water: 'Traditional measures for flood risk management such as river dikes can no longer solve the major problems caused by climate change. We have to teach the city to adapt to the climate.' Alderman Hsu accompanied the mayor to the Netherlands and Japan to see how they work with water. 'In addition to deepening and widening rivers and improving drainage, we can use a range of methods as a local government to limit flood risks. Prevention consists of projects and campaigns. That is why Kaohsiung is also involving local residents. We are encouraging the public to establish communities and dedicated government teams are organising disaster training. We are also informing citizens about ways to change their own localities. Innovative infrastructure Of course, Kaohsiung itself will also be looking at the city to find solutions. But space is scarce in the metropolis. 'So we have transformed school playgrounds, green strips and parking lots into small water storage locations. In Ben-An, a very densely populated part of the Sanmin district, we created an ecological retention park by digging out a car park. The paving in all new public facilities will be permeable.' Kaohsiung will also be creative with buildings like the fruit and vegetable market in Sanmin. The market has been here since 1975 and it is the city's largest with 300 stalls. The government has earmarked more than 35 million euros to establish Taiwan's first fruit and vegetable market as a tourist attraction with flood prevention. The cellar will be a car park on normal days and store water during heavy showers. In addition, the city is improving the drain and opening a new access road. 'The construction will help tourism, improve transport and prevent flooding.' New Orleans As well as engaging in major projects, Kaohsiung is also looking for ways to retain water on private property in order to enhance the sponge potential of the city. Frans van de Ven, a researcher at Deltares, is impressed by the Taiwanese approach: 'The example given by Kaohsiung is helping Deltares to devise practical solutions. For example, we are now working on a sponge city concept for New Orleans as well. We can use our hydrological models to make an assess­ ment of the best way to retain rainwater, and to decide when and where that should be done.'