Water becomes an ever more decisive factor in urban development – especially in the agglomerations of South East Asia. In Phnom Penh we witnessed remarkable ways of how the city – and its people – have learned to live with the all-present water.

City in the water A metropolis that is regularly under water is an idea hard to cope with. We are used to imagine big cities being built on solid grounds – not into marshes or muds. Insecure riverbanks or rushing streams. Cambodian capital Phnom Penh but literally raises from the water. It is subject not only to a climatic condition that brings month-long torrential rains, but is also exposed to a unique and highly volatile geographical situation in which three rivers form an immense intersection of quickly changing streams and waterways. Taking account of the country´s poor economy which still bears the effects of the gruesome excesses of Khmer Rouge Stone Age Communism, resulting in Phnom Penh´s vast stretches of informal settlements, shelters and barracks, one may easily imagine dystopian urban sceneries like in Hollywood movie “Waterworld”. Seeing the city´s quickly growing skyline of high-rises on the one hand, but considering as well the fact that Cambodia counts as one of the least developed countries in the world – but one which will bear the strongest effects of climate change – a Blade Runner world builds up before the mental eye, but all flooded. On a more positive note, however, the people of Cambodia are on familiar terms with water since ages. They know how to live with – and in – it. Such, water bodies have become a key component of Phnom Penh´s “liquid urbanity”, determining to large extent the local life style and settlement culture. The soaked city is a normal condition. Phnom Penh has plenty of urban water stories to tell.

SURE We had chance to visit Phnom Penh multiple times in the context of the SURE funding program. SURE (“Sustainable Development of Urban Regions”) comprises 10 project consortia with approx. 150 partner organizations that investigate urban development issues in South East Asia such as sustainable construction, urban risk management, or local stakeholder participation. Our chair Digital City Science leads the Facilitation and Synthesis Research (FSR) for this program – a task that also implies local visits to the project partners and the project implementation sites.

Water leitmotif On such purpose, we travelled to Phnom Penh to meet two Cambodian SURE project partnerships, just after concluding the annual status conference in Bangkok end of September. From SURE, we knew already about the elemental role of water for urban development in South East Asia. In Bangkok we had visited “amphibic” urban design projects – public parks, for example, that would turn into wet playgrounds after strong rainfalls. Phnom Penh, however, made the full scale of the topic even more evident. In this place, millions of people are squeezed on river banks, marshes, and wetlands, exposed to large rainfalls and floods. Here, water is the key urban development issue – an urban leitmotif. The one contributing factor is the regional climate. Yearly rainfalls in Phnom Penh amount to about 1400 mm – twice the amount of Hamburg (which by no means is a place of low precipitation). With the rainy season lasting nine months, one third of the year are rain days. In the peak time during September-October, one third of the entire agricultural land of the country is under water. Then, Villages become literally “floating”, with the houses either becoming boats themselves, or being lifted up on stilts meters above ground to let them hover over the quickly raising water levels. While the current situation is extreme already, the future, however, will still accelerate the conditions.
Cambodia, along with the Philippines, is Southeast Asia’s most vulnerable country to the effects of climate change.

Three Rivers The second factor are the rivers of Phnom Penh. The city is set on the banks along – or better say: between – three large streams whose flow behavior is volatile to a high degree. The riverbeds of Mekong, Tonle Sap, and Bassac form a peculiar x-shape on the map. The immense Mekong is the arteria of Indochine, collecting water from the entire subcontinent. Still hundreds of kilometers away from the delta, the riverbed in Phnom Penh is already two kilometer wide. During the monsoon season, it will multiply its capacity by factor 4. The massive increase of water pressures in turn induces a peculiar phenomenon of the second largest river – the Tonle Sap will change its direction of flow. While in the dry season the Tonle Sap runs from the country´s largest lake of the same name, it runs towards the lake during the monsoon times, increasing its size fourfold, and its depth 5 times.

Urban Development Issue One result of these massive and changing influxes of water is the existence of lakes, wetlands, and marshes in and around Phnom Penh which function as sponge-like buffers. However, recent drainage and infilling of these areas for the sake of urban expansion and construction have exacerbated the flood risk dramatically. The landfilling proceeds on high speed (the majority of the 25 lakes have been filled already) although it is clear enough that millions of people will be affected. Recognising the research deficit about the socio-spatial implications and long-term effects, however, one of the projects in the SURE program – PolyUrbanWaters – is now developing tools to model urban water dynamics, and to activate the respective engagement among urban communities and policy makers. With a similar target, our team building the open GIS toolbox TOSCA at the chair of Digital City Science has created a prototype tool for water management and precipitation, too. This in turn may feed into our new project RESCUE MATE which is to provide intelligent situation monitoring for rescue operations and risk management in the case of flood events in Hamburg.

Tuc Tuc Besides the requisite scientific and technological means for dealing with urban waters, human intelligence, adaptability, and creativity are still the main counterforces. Our excursions around Phnom Penh provided good anecdotal reference. – To move to some conference venue on a university campus in the outskirts, three of us had squeezed into one of these motorized micro cabs (“Tuc-Tuc”). Rapidly moving through informal settlements, we registered with astonishment how shags and shelters were not only sitting at the edge of poddles, lakes, and water flows – but also right within them. The slum was literally floating: the water was around, between and inside the shelters. Inside, household items were swimming on the ground. The tour, however, came to a climax when the tiny Tuc-Tuc neared a giant poddle in which a pickup truck had just submerged beyond its wheels. Our driver – completely unimpressed – geared up. Pushing aside children and chicken in the street, he steered close to the edge of the poddle-lake and dove into. The moment the vehicle started to tip towards the center of the poddle (and when the local project director screamed “I am too old for this!”), the driver rebalanced the vehicle by suddenly leaning outside of the Tuc Tuc like a surfer. Seconds after that stunt we had safely reached the other “shore”. River night. We hadn’t seen the Mekong yet, but were decided to use our last night in Phnom Penh to explore the big stream (for some people, big rivers are magnetic). Sow we steered towards the central high-rise district that was newly pulled up right on the river bank. Having no better idea of what to do, we eventually jumped on deck of a ferry to the other side of the river, just in the moment when it had started moving. Almost nobody was on the ship; it was far past midnight already, there was no security whether we could return still tonight. We saw the skyline behind us grow smaller, the shoreline disappearing into darkness – just as if one departed a sea port. Finally arrived, there was little was to be seen on the other side, however. We glanced at the heavily littered shore. The
street to the ferry stop was empty except one young man who kept repeating to us the Khmer name of his country: “Kampuchea … Kampuchea …”. Happy to see another ferry coming, we headed back to the urban side of the Mekong. On the quays we came across a flying outdoor restaurant that still served food and drinks. Soon, however, a heavy rain set in that would continue until the morning. Around 3 in the morning, the young people who ran the place started removing plastic chairs, tables, and umbrellas. Within seconds, they were soaked wet. Taking off shoes and shirts, hurrying around half-naked and barefoot in the warm rain, they obviously enjoyed being part of the all-embracing wetness. – When our taxi left to the airport few hours later, still before dawn, a man on the sidewalk opposite the hotel took a lengthy shower with a water hose.