(THIS ARTICLE IS MACHINE TRANSLATED by Google from Norwegian)
All over the world, climate change makes it necessary to focus on the waterways of cities and towns. Water is necessary for the natural and human life of the cities, but also a threat in the form of torrential rain and floods.
During the UN Habitat World Forum in Katowice, Poland in June, contributed Habitat Norway with articles on the role of rivers in Oslos urban development. The event "New Community Knowledge and Practice on People Centered and Resilient Spaces related to Urban Rivers" had several examples of river development. Among others, Regina spoke here Opposite from the NGO Kounkuey Design Initiative in Nairobi. She worked systematically in kibera (the world's largest informal settlement with 1 million inhabitants) for coordinated development and operation of the water areas in the settlements. Systematic knowledge building and evaluation of projects was shared with the citizens as a basis for general participation. "Data is the new gold!", said Opondes.
From Indonesia, Vanessa presented Manuturi from KotaKita (NGO with the slogan: "A City for All") who expanded the urban space through site development with floating piers (board walks). She showed how upgrading and expanding floating docks dealt with challenges related to waste and the need for public services.
Climate budget and climate management
The English economist Kate Raworth argues in his "doughnut economy" [model that balances between human needs and the planet's tolerance limits, editor's note. ] well because all the dimensions of sustainability must be handled holistically and at the same time.
Sosial sustainability is just as important abroad as at home, and indirect greenhouse gas emissions caused by Norway outside the country's borders are just as important to limit as direct emissions here in the country. To deal with the climate challenges, we need comprehensive climate budgets, something Oslo municipality has developed and used for the past 6 years, and which is now to be introduced at state level. The climate budget is part of the annual municipal budget processes, and covers all sectors. In contrast to "forecasting"/scenario thinking, where various trends are projected into the future, "backcasting" – where a future desired result is determined and necessary measures are chosen along the way to achieve the result – is an important approach.
Oslo municipality leads an international C40 network to spread best practice and develop the use of climate budgets. Mumbai City have adopted the tool and have created an impressive one climate plan. The recognition that city and country are dependent on each other (rivers run through both) has led to the climate budget applying to the entire Mumbai Metropolitan Region, and not just Mumbai city.
Flood risk
For over 30 years, Oslo has focused on the city's 10 elvis. Based on an older strategic park plan from 1949, the rivers have been allowed to develop with varying degrees of biodiversity and urban character. Today, the open or closed rivers are among the most important structuring elements in urban development. The municipality has an extensive program for improving the water and sewage network, but just as important is the reopening of waterways laid in pipes.
But the strategy from the 1960s and 1970s of putting them in pipes is outdated, because the pipe systems cannot handle the quantities of water resulting from today's extreme weather and future torrential rain.
Local stormwater management can take care of larger quantities of water and also contribute to biological diversity and experience values locally. Along both Akerselva and Alnaelva, the riverbanks have been acquired for public traffic over the past 2-3 decades, local waterfalls and river parks have been opened up and civil society has mobilized for various activities. Historically, older industrial buildings have been located close to the river bank in order to be able to utilize the energy from the bodies of water. The experience gained from the later development work, which must also take care of flood risk, means that the area section of the municipal plan now requires new building measures to be 20 meters away from larger rivers, and 12 meters away from streams. Incorporating rivers and streams into the urban fabric is still common today, even if there is occasionally a conflict between safety for people and the need for untouched nature that ensures biodiversity.
Threats and resources
Oslo is a relatively small city with sloping terrain, but is still prone to flooding. Adaptive re-use of older buildings where new usage needs are fitted into older structures is common, for example in Nydalen, Vulkan and similar areas. Nevertheless, the flood risk in torrential rain for such low-lying areas in the city is significant.
River banks are also often dark and poorly lit areas where it is unsafe for people to move. Assaults, rapes, robberies, and the sale of drugs occur in some places. Vulnerable groups such as the elderly, women, girls, immigrants and LGBTI groups are particularly vulnerable in such environments. The rivers therefore require careful planning and balancing of activities to be good arenas for people's urban life.
Vulnerable groups such as the elderly, women, girls, immigrants and LGBTI groups are particularly vulnerable in such environments.
When new development areas are carefully planned, the interaction between rivers, streams and buildings, which provide passive supervision from the residents, can provide added value for both nature and people. Since the 1970s, principles of Crime Prevention Through Environmental Design (CPTED) have been developed. These principles are based on keeping unwanted elements away (cf. Oscar Newmann: Defensive Space) rather than promoting the desired social life and behaviour.
Later, for example after the 22 July attack in Oslo in 2011, more inclusive principles were developed (compare Grunnsikring plan for Oslo city centre). Here, the aim is to make the public spaces open to the general public and through human presence and activity to make the urban spaces safer. These principles are also relevant for securing the riverbanks. Through differentiation of functions in the public space and shielding of different activities, but in a transparent way, different user groups can stay safely side by side (cf. Eva Storrusten and Ellen de Vibe: "The city of women is everyone's city", article in Arkitektur number 3, 2022). Oslo municipality has, for example, established temporary play facilities in Ofeliagangen in Grønland and in Christian Frederiks plass near Oslo S. By introducing entirely new activity opportunities, new user groups take up the urban spaces, and previously unwanted activities such as drug sales cease.
Oslo city center got its own lighting plan 20 years ago. The aim was to ensure increased safety and to highlight the city's architectural qualities. Lighting of the parks and river banks along Akerselva was an important area of effort. The lighting was to shine both downwards and upwards so that human figures were clearly visible to those coming in the opposite direction. However, we quickly discovered that illuminating the river's water surfaces also had clear disadvantages, as it could negatively affect the fish's mating. We recognized that the wildlife also had to be taken care of.
Rivers for recreation and social city life
The river's value for recreation, welfare and social life is obvious The rivers weave through the city's structures and provide the basis for short-distance, urban outdoor life. Experiencing nature and wildlife, or fishing for your own food, also provides clear benefits. This is particularly important for people without a tradition of the outdoors. The upgrade of Bjerkedalen park in Groruddalen (Oslo municipality and Dronninga Landskap AS) has visually open and safe footpaths along the water surface, a local cafe and stormwater management, all adapted to the residents' needs. The park has become an important social meeting point for the surrounding residents.
The rivers weave their way through the city's structures and provide the basis for short-distance, urban outdoor life.
Over 30 years, Akerselva's outlet, as part of long-term thinking that outlives our own lives, has been excavated with new parks and footpaths. The river's outlet towards the sea at the Sukkerbiten peninsula, an area with a strong harbor feel, quickly attracts bathers when the quayside is opened to public traffic.
The rivers can also have an important role as creators of local identity. Through voluntary organizations such as Oslo Elveforum, local sports teams and art groups, many different connection points have been established. Regardless of age, ethnicity and class, a tradition of cultural activities has emerged. Every autumn, for example, river walks are carried out in the evening with various illuminated activities along the various rivers.
Plants do the work
The use of nature-based systems (NbS) to solve our climate challenges is essential to achieving lasting sustainability. Countries such as China and cities such as Hong Kong have understood that urban development must work with and not against nature. China uses the term "sponge city" to explain that extreme weather must be handled by allowing nature, vegetation and the soil to digest and handle large amounts of water that occur during torrential rain and floods.
Biophilic design, the use of natural elements to make facilities and buildings more resistant to extreme weather, is now proposed to be rewarded in certification systems such as BreeamNor for sustainability in the construction industry.
An example of NbS design was then along Groruddammen Alna river was worked up. Instead of greenhouse gas emissions from the extensive removal of contaminated soil in the area, the municipality chose to use principles of natural remediation (phytoremediation) where certain species of grass and shrubs were planted to clean the soil in 2–3 years. Instead of depositing hazardous waste or using plastic materials for encapsulation, nature's own materials can do the job.
When Fjordbyen was developed, the municipality and the Swedish National Antiquary demanded water accounting
Good river development requires clear legal tools to be able to be balanced against other important needs, such as the construction of housing. When Fjordbyen was developed, for example, the municipality and the National Archives demanded water accounting so that the role of the water surface in the development of the city center was not reduced. The principle was that for every square meter that was refilled in the harbor basin, corresponding new water areas were to be created, comparable to the excavation of Akerselva to the railway tracks on Oslo S.
Blue-green factor
Another example is the Norm for blue-green factor (BGF), which must ensure both green experience values, well-being-promoting infrastructure and sound, local stormwater management. Based on different building densities in urban areas, BGD has differentiated coefficient requirements for water and green areas (parks: 1,0, streets: 0,2 etc). The developers themselves decide which measures they want to implement. The sum for various measures is calculated by multiplying the area or the number of trees/bushes for each measure, which is then added to a total that corresponds to the total requirement for the individual area. The requirements can be achieved in different ways by using large lawns, smaller lawns with some large trees or vertical gardens on house facades. Water-permeable surfaces can be used on the ground, rainbeds or sunken places or drainage tanks under sports surfaces to deal with stormwater and extreme weather. Both the city area's floodways, planting and local drainage must be assessed together for the individual building measures.
Oslo's experiences with river development undoubtedly contribute to focusing on how floodways and waterways as well as the green structure, which the urban rivers form part of, can meet future living conditions and climate challenges.
