Green Infrastructure to Prevent Floods: Floodable Parks

By Corina P. Fraile M. and Kathryn Novkov

Climate change has affected water resources in various ways around the world, while some cities have to look for ways to manage it due to shortages, some others have suffered from sea level rise and floods caused by increased downpours. In urban areas, the rainwater runs off the pavement and roofs and, through stormwater drains, ends up in the waterways as polluted stormwater (Melbourne Water, 2017). In recent years, there have been intentions to implement practices that take advantage of water resources in a more efficient way without interrupting its natural cycle and without affecting the ecosystems associated with them. Water Sensitive Urban Design seeks to reduce the harmful effects of stormwater in rivers and creeks as it includes strategies to capture rainwater, with floodable parks and public spaces as one option (Perrozzi and Montiel, 2020).

What are floodable parks?

Floodable parks are designed to be flooded and manage the water they receive in the most efficient way. They help mitigate the risk associated with hydrometeorological events and lower the contamination of bodies of water. They can serve a key role in risk mitigation, acting as a part of a system of quick alert, evacuation plans and monitoring possible floodings. The way they capture and manage water varies from place to place, taking into account the context of each city and its context, but their aim is to recycle rainwater and allow the natural flow of bodies of water. Flooding parks require big underground reservoirs to store the fallen water and use them when required, during times of drought for watering plants, or to slowly drain water after heavy rains in a way that the city system doesn’t overflow. This model of spaces is an innovative referent for the development of public spaces in areas that are prone to suffer from flooding, because they help preserve not only the nearby infrastructures by retaining or redirecting rainwater, but also protect watercourses from urban sprawl by integrating them into the public space system of the city (Perrozzi and Montiel, 2020).

Design for the Chulalongkorn University Centenary Park in Bangkok, Thailand. (Holmes, 2019)

Why are they important?

As climate change has accelerated, flooding has become more common due to changes in the water cycle that have led to an increase in downpours, meaning a lot of heavy rain coming down at once. When rain falls in shorter and more intense downpours, it is more difficult for stormwater drains to contain the water which leads to an increase in flood events. Flooding is very dangerous for cities because it can contaminate drinking water, leave people without electricity, damage property, cause accidents, and in extreme cases can even take lives. (Climate Council, 2022) On top of the plethora of negative consequences of flooding, it is also a very heavy economic burden on cities that can cost them millions of euros (Dobrovičová, Dobrovič, & Dobrovič, 2015). Flood parks like the ones we describe in this blog, can be extremely helpful by keeping most of the water to one area of the city and then absorbing it through its permeable surface and releasing it slowly after the flooding event, which prevents damage to the physical infrastructure of the city. This is obviously one of many solutions there are for flooding and it should not be the only green infrastructure that cities built to minimize flood damage, however, these could potentially be very useful for cities if built in areas that are more prone to flooding such as areas that are lower in elevation (Urban Green Up, 2020 & Climate Action Tool, 2017).

Floodable Park Víctor Jara o Zanjón de la Agua, Santiago, Chile. (Perrozzi & Montiel, 2020)

Some examples

Kirkkojärvi Park, Finland

Kirkkojärvi Park before and after heavy rains (Loci, 2022)

This example is of a flood park located in one of the most populated parts of Finland. The idea was to bring back a lake that was drained decades before. How this works is that there’s now an open field where the lake used to be, and the area around the field was raised so that when it floods, the field is flooded, while the areas around it remain dry and there is once again a “lake”. This not only helps to prevent damage to the infrastructure such as transportation routes around the area, but also creates an aesthetically unique and interesting landscape that raises awareness about flooding and climate change (Loci, 2022).

La Marjal, Spain

Floodable Park La Marjal in Alicante, Spain (CEOE, 2021)

This is the first urban floodable park in Spain and it helps to manage floods caused by heavy rains in Alicante. It has a pond that retains purified water from a purifying plant next to the park and, during periods of rain, the vegetated areas around the pond fill up to reach its maximum capacity (El Independiente, 2019). It has in total 3,6 hectares of flooding area and it can store up to 45.000 m3 of water. In case of heavy rains, it has a monitoring and alert system that lets the authorities know in case of an emergency. The collected water is led to a purifying facility and some of it is used for watering of green spaces. The species planted in the park not only mitigate the effect of floods but they also preserve biodiversity as they serve as refuge for fauna and flora of the region (CEOE, 2021).

Benthemplein, Netherlands

Watersquare Benthemplein in Rotterdam, The Netherlands
(De Urbanisten, n.d.)

This example is of a water square that was built in Rotterdam. The idea was to transform the pavement of this area and create a square that floods with water at times of higher intensity rain and then drains slowly to prevent overflow of the storm drains and sewage systems. This project not only helped decrease the damage from floods to this part of Rotterdam, which is especially important because climate change has particularly increased the number of short but intense downpours in Rotterdam, but it also helped bring together the community. This project was inspired by students who wanted a new social space and asked if this would be possible. Their wishes for better social infrastructure were in line with planner’s wishes for physical infrastructure to mitigate flood damage and so by combining these two wishes they were able to create this flood park. This example goes to show that while floodable parks are a great solution to help prevent flood damage they also usually have many other benefits such as creating a visually aesthetic new physical space that everyone can enjoy (Gemeente Rotterdam, 2014).

References

CEOE. (2021, November 25). La Marjal, un parque urbano inundable diseñado para mitigar los efectos de las lluvias torrenciales. Confederación Española de Organizaciones Empresariales: https://www.ceoe.es/es/ceoe-news/sostenibilidad/la-marjal-un-parque-urbano-inundable-disenado-para-mitigar-los-efectos-de

Climate Action Tool. (2017). Manage floodwater: Create a floodable park or open space. Massachusetts Wildlife Climate Action Tool: https://climateactiontool.org/content/manage-floodwater-create-floodable-park-or-open-space

Climate Council. (2022, March 02). Everything you need to know about floods and climate change. Climate Council: https://www.climatecouncil.org.au/resources/climate-change-floods/

De Urbanisten. (n.d.). Watersquare Benthemplein. De Urbanisten: https://www.urbanisten.nl/work/benthemplein

Dobrovičová, S., Dobrovič, R., & Dobrovič, J. (2015). The Economic Impact of Floods and their Importance in Different Regions of the World with Emphasis on Europe. Procedia Economics and Finance, 34, 649-655. https://doi.org/10.1016/S2212-5671(15)01681-0

El Independiente. (2019, August 25). Así funciona el parque inundable que evitó daños en el día más lluvioso en 160 años. El Independiente: https://www.elindependiente.com/futuro/2019/08/25/asi-funciona-el-parque-inundable-que-evito-danos-en-el-dia-mas-lluvioso-en-160-anos/

Gemeente Rotterdam. (2014). Benthemplein. Gemeente Rotterdam: https://www.rotterdam.nl/wonen-leven/benthemplein/

Holmes, D. (2019, April 19). Chulalongkorn University Centenary Park – green infrastructure for the city of Bangkok. World Landscape Architecture: https://worldlandscapearchitect.com/chulalongkorn-centenary-park-green-infrastructure-for-the-city-of-bangkok/

Loci. (2022). Kirkkojärvi Flood Park. Landezine: https://landezine.com/kirkkojarvi-flood-park/

Melbourne Water. (2017, September 28). Introduction to WSUD. Melbourne Water: https://www.melbournewater.com.au/building-and-works/stormwater-management/introduction-wsud

Perrozzi, A., & Montiel, N. E. (2020, May 1). Parques inundables: el rol del espacio público en la gestión del agua. Transecto: https://transecto.com/2020/05/parques-inundables/

Urban Green Up. (2020). Floodable park. Urban Green Up: https://www.urbangreenup.eu/solutions/floodable-park.kl