European Union flag

Sealed surfaces and heavy rains increase the flood risk in the Estonian municipality. In response, Sustainable Urban Drainage Systems reduce the risk and enhance climate resilience.

Download the Report

Key Learnings

  • Collaboration drives innovation: Partnerships between local governments, research institutions, and environmental organisations have led to practical, cost-effective solutions. Working together Viimsi Municipality, Tallinn City, the Estonian University of Life Sciences and Baltic Environmental Forum created two demonstration sites – Viimsi Manor Park and a parking lot in Viimsi’s centre – that manage water more sustainably while enhancing urban spaces.
  • Developing a smart stormwater system: A smart stormwater management and e-monitoring system supports emergency prevention and timely response. It collects real-time information from weather stations, flow meters and other sensor devices and transmits it to the desktop of a municipal specialist who takes the necessary measures in case of flooding.
  • Additional benefits: Applying an integrated flood risk management approach has many additional benefits regarding economic viability, nature conservation, water quality and amenity, thus delivering multiple benefits to society.

About the Region

The Viimsi municipality is located in northern Estonia and borders its capital, Tallinn. Home to more than 23,000 inhabitants its municipality’s centre – Haabneeme borough – has various facilities, such as schools, kindergartens, shopping centres and spas, forming a vibrant urban environment in Estonia. Haabneeme borough provides community and public services with apartment buildings, private properties and green areas surrounding it.  Like the rest of Viimsi, Haabneeme struggles with excessive ground moisture, due to its location on a peninsula with blue clay – an impermeable material, hindering water to percolate deeper into the ground – subsoil.

Climate Threats

According to the Estonian Environment Agency’s 2015 future climate scenarios, Estonia is expected to experience significant changes in its climate by 2100, including:

  • Rainier winters and a lack of permanent snow cover and more frequent temperatures around 0°C, leading to alternating thaw and frost, ice formation and occasional periods of frost and snow;
  • Warmer, longer summers with more frequent and prolonged heatwaves and droughts, as well as more frequent extreme weather events such as rain, hail and storms;
  • By 2100, average annual temperatures could rise by more than 4°C, with precipitation and wind speeds also increasing significantly, especially during winter and spring.

Climate change is already affecting many densely populated urban areas across Europe and beyond. Heat-absorbing, sealed surfaces combined with limited green spaces worsen the impacts of extreme weather. When heavy rain falls on impermeable surfaces like roads and pavements, water cannot soak into the ground, leading to flooding and overloading drainage systems.

Local governments play a crucial role in building and maintaining stormwater management systems in their municipalities, as this is one of their key functions according to the public administration system. Strengthening their resilience to climate change, particularly managing flooding and heavy rains, has become increasingly urgent. This includes developing rainwater management solutions such as Sustainable Urban Drainage Systems.  As intense and frequent downpours become more common, existing stormwater infrastructure is often unable to cope and expanding it can be expensive. In many cases, nature-based solutions that mimic natural water cycles offer a more cost-effective and environmentally friendly alternative. These systems help manage stormwater by collecting it, slowing its flow, encouraging infiltration, and allowing evaporation, all of which help filter pollutants. Sustainable Urban Drainage Systems can include green roofs, green walls, permeable pavements (Figures 1 and 2), filter strips, soakaways, infiltration trenches and basins, swales, rain gardens, stormwater planters, ponds and constructed wetlands.

Figure 1: Car park with permeable asphalt. Image Credit: Viimsi Municipality.
Figure 2: Car park with permeable grass pavement stone. Image Credit: Viimsi Municipality.
Figure 3: Waterfall to prevent the rapid flow of water. Image Credit: Viimsi Municipality.
Figure 4: Recreational area (terrace and bridge) at the ditch for park visitors. Image Credit: Viimsi Municipality.

Sustainable and climate-resilient stormwater management systems

In response to the increasing flood risk, Viimsi municipality installed several Sustainable Urban Drainage Systems across the town. Examples include Viimsi Manor Park and the parking lot in Haabneeme centre. A team, involving municipal civil engineering specialists, storm water and landscape experts from the university, construction designers and construction companies, installed the Sustainable Urban Drainage Systems within the framework of the LIFE UrbanStorm project to increase the urban stormwater management capacity all across Estonia. Viimsi municipality has developed and tested sustainable and climate-resilient storm water management systems to better adapt to climate change, particularly to manage the floods caused by heavy rain.

More specifically,

  • In Viimsi Manor Park, the Sustainable Urban Drainage System manages stormwater in an environmentally friendly way – the system drains excess water in the soil, reduces the flow rate in the central ditch to prevent erosion of its banks, and makes the park more attractive and accessible to local residents.
  • In the Haabneeme parking lot, the project team constructed a Sustainable Urban Drainage System to slow down rainwater runoff and prevent flooding. They based the design on the expected rainfall from an average 60-minute rain event. To manage excess water, they dug a new drainage gutter at the back of the parking lot to collect water from the drainage system beneath the new parking area. They also created test sections with three different top layers – porous asphalt, permeable paving with gravel, permeable paving with grass – to evaluate water permeability. In addition, they tested asphalt made of recycled plastic as an alternative surface material.

The Sustainable Urban Drainage System has been monitored after installation, with the following results:

  • Draining 36,000 m³ of rainwater per year and 18 hectares of flood resilient area.
  • The soil water regime of the central part of Viimsi Manor Park has improved. The soil in the area has better drainage capacity, and the reduced flow rate protects the ditch banks from erosion, making the park more popular among the locals.
  • During heavy rain, no water accumulates on the surface of the parking lot thanks to three types of permeable pavement: permeable asphalt, grass pavement, and stone pavement with crushed stones in its joints. In winter, the surface remains ice-free and does not rise due to freezing. Rainwater drains the fastest through the permeable asphalt and the stone pavement with crushed stones in joints, while the grass pavement slightly slows down runoff.

Further project outputs include:

  • Climate Change Adaptation plans for Tallinn City and Viimsi Municipality, providing strategic frameworks and addressing various sectors, such as spatial planning, water management and tourism;
  • A Handbook and other practical guidelines for municipal specialists, designers, and engineers who plan to install similar solutions.
  • Training has increased the knowledge of water management specialists of Estonian municipalities and designers and engineers of stormwater management systems. This included two-day training sessions in North and South Estonia for local municipality staff and municipal water companies. More than 100 participants from 20 municipalities participated to the trainings. Similarly, two-day training sessions for stormwater management engineers and designers in North and South Estonia engaged about 150 participants.

Municipalities need new solutions to better cope with future weather conditions, to adapt to the climate change. Novel Sustainable Urban Drainage Systems in Viimsi Municipality combine different technologies and materials and integrate green solutions into the artificial environment, linked with smart solutions and circular economy principles.

Alar Mik, Deputy Mayor of Viimsi Municipality

The monitoring results of the new Sustainable Urban Drainage Systems show that these solutions are cost-effective and have helped prevent flooding in the area. For example, the construction and maintenance costs of a park with a permeable surface are comparable to those of a park using conventional materials. Similarly, building a car park with a permeable surface costs only about 9% more than a traditional asphalt car park, while maintenance costs remain the same, requiring only a few specific operational instructions.

Summary

Climate projections for Estonia indicate significant changes in temperature, wind patterns, and rainfall by 2100. Existing stormwater systems are already struggling to cope with intense downpours, leading to urban flooding due to inadequate drainage infrastructure. Local governments play a key role in addressing this challenge, as they are responsible for planning, building, and maintaining stormwater management systems in their municipalities. Viimsi municipality developed and tested Sustainable Urban Drainage Systems at two demonstration sites to reduce the flood risk from heavy rains. In Viimsi Manor Park, the measures focused on slowing down water flow and improving soil drainage. In the central Haabneeme parking lot, the specialists installed three types of permeable pavements with filter strips to test their effectiveness. Monitoring results have shown that these Sustainable Urban Drainage Systems are cost-effective and have successfully prevented flooding in the target areas.

Further Information

The work presented in this adaptation story is part of the LIFE UrbanStorm project.

This project has received funding from the European Union’s LIFE programme under grant agreement LIFE17 CCA/EE/000122.

Website of LIFE UrbanStorm Project - https://urbanstorm.viimsivald.ee/

Contact

Tanel Mätlik
Project Manager
tanel.matlik@viimsi.ee

Keywords

Climate Impacts

Flooding, Storms

Adaptation Sectors

Urban, Water management

Key Community Systems

Critical Infrastructure, Ecosystems and Nature Based Solutions, Water Management

Countries

Estonia

Funding Programme

LIFE - Environment and climate action

Disclaimer
The contents and links to third-party items on this Mission webpage are developed by the MIP4Adapt team led by Ricardo, under contract CINEA/2022/OP/0013/SI2.884597 funded by the European Union and do not necessarily reflect those of the European Union, CINEA, or those of the European Environment Agency (EEA) as host of the Climate-ADAPT Platform. Neither the European Union nor CINEA nor the EEA accepts responsibility or liability arising out of or in connection with the information on these pages.

Language preference detected

Do you want to see the page translated into ?

Exclusion of liability
This translation is generated by eTranslation, a machine translation tool provided by the European Commission.