City news: People in action

5 October 2020

Catching rain in Bratislava

After recurrent floods of the River Danube in the twentieth century, the City of Bratislava has built the infrastructure to face expected floods for the next 100 years, but this will not be enough to make the city resilient against frequent and heavy rainfalls. One of the most immediate solutions is to implement measures of increasing water retention, which can be through green infrastructure, making soils more permeable, or through grey infrastructure, which contains and reuses, or channels surplus water. While municipalities can do this in public spaces, they are often restricted when it comes to private properties.

So, Bratislava has recruited its residents. In 2016 the city created a subsidy for sustainable water management installations. Private organisations and households can apply to build water reservoirs and rainwater gardens, small green roofs, permeable pavements, etc. The subsidy always covers 50% of total costs of the installations, up to a maximum amount of €1,000 per application. In addition, applicants receive consultation on their project’s implementation and dissemination provided by the city of Bratislava.

After a slow start in 2016, with six completed projects, the initiative has picked up in recent years, with more than €37,000 invested in different projects in 2019. This year, due to Covid the budget was cut, and the total sum of €20,000 will be invested. Most applicants used the subsidy for purchasing and installing rainwater catchment tanks or drainage systems, and reusing the collected water for irrigation. One fifth of the projects created green roofs. Others replaced impermeable surfaces with permeable materials.

Putting heads together for fresh ideas in Dresden

While people in Bratislava are worried about rainfall, Dresden residents have the heat to worry about and despite ongoing renovation of the building stock, many poorly insulated buildings leave residents vulnerable to extreme temperatures.

Experts, such as representatives of the building industry, urban development experts, scientists and researchers, and 178 residents put their heads together to study the issue and find solutions, building a HeatResilientCity.

With data and the residents’ feedback in hand, experts used computer simulation to analyse potential solutions, and residents weighed in to select the ones they preferred.

Putting the expertise of scientists and the expertise of residents together, Dresden developed an inclusive process that meets residents needs and implements effective solutions to improve their wellbeing.

As residents were involved in the process, they understood the importance of the measures that were put in place and were more likely to implement them. This is especially important, since some measures involved behavioural change, for example opening windows at night to create crosswind.

Most citizens indicated a preference for solutions that would create shade and add green spaces and water elements to their living environment. So, housing companies have to take green spaces and extra shade into consideration in current and future open space development. The first trees will also be planted this autumn. A flowerbed has been introduced in the area to also improve biodiversity, and an additional flowerbed is already being planned.

Locals can now refill their bottles at four ‘Refill’ stations. These are shops and stores that have signed up to the ‘Refill’ national initiative, offering people to refill their bottles for free in their establishments.

Read Bratislava’s full case studyRead Dresden’s full case study

*These case studies are part of the Covenant of Mayors collection of case studies and have been presented today at the SDG 11 Day during the United Nations Economic Commission for Europe‘s (UNECE) Sustainable Cities Week. At the same event we presented the Urban Adaptation Support Tool, which takes cities through all the steps needed to develop and implement an adaptation strategy and refers to valuable guidance materials and tools.


  • Saving the world with tomatoes

    Ghent has won a UN award for the way the Belgian city puts food on the table. See the ingredients of Ghent’s food policy.

    5 minutes read
  • Let it rain

    What would happen if cities let rain run its course? Paris is becoming a permeable city and with rain, other positive effects have trickled in.

    5 minutes read
  • CARbon free

    At the heart of Prague's new transport policy is a more integrated, energy efficient and environmentally friendly public transport system.

    5 minutes read
  • Snake hunt

    Grenoble Alpes Metropole's magical Tour Sans-Venin is famous for its power to keep snakes at bay - for the metropole, it was the perfect place for an enormous treasure hunt.

    6 minutes read
  • Branching out

    Planting urban trees to boost climate action and citizen wellbeing is a growing trend, but what does it take to get it right? France's greenest city, Angers, shows how it should be done.

    5 minutes read
  • My future city 2030

    Porto has a goal to reduce its greenhouse gas emissions by 50% by 2030, but thinking green requires a strong vision of the future.

    6 minutes read
  • Bankable rivers

    Two decades ago, Wroclaw's river rose up and swallowed the city, killing 55 residents. 162,000 people were evacuated and the city sustained half a billion euros in damages. The city’s response? Embrace the river, develop it, and make it part of urban life.

    6 minutes read
  • Street smart

    Walking down Bogoridi Street in Burgas feels like stepping into the past – you might not suspect that this wide, sand-hued street is one of the most high-tech public spaces in Europe. The old-style streetlamps are more than they seem...

    5 minutes read
  • Pumping Heat

    You don’t need a volcano for geothermal energy that works well – in fact, it’s the relatively moderate underground temperatures that allow the system to provide not only heating during the winter, but also cooling during the summer months.

    4 minutes read
  • The world is over. Time to save it.

    We did our best to save the world, but now it’s too late for that. This is the premise of the game Age of Energy, which is harnessing its addictive power to cajole young people into energy saving behaviour.

    5 minutes read