7 types of nature-based solutions to consider for your next project

Nature is a vital ally – we have to look after it like we look after our homes.

Civil and infrastructure engineers have an important role to play in incorporating nature into the way we design, build, operate and maintain infrastructure.

What are nature-based solutions?

Nature-based solutions (NBS) are actions or measures inspired by, supported by, or copied from nature.

They may involve protecting, managing, or enhancing existing natural solutions and creating engineering solutions that mimic natural processes.

What are the benefits of nature-based solutions?

If implemented carefully, they can deliver a host of benefits for people and the planet. NBS can:

• Deliver infrastructure services in their own right. For example, they provide mental and physical health benefits by creating green spaces for people to enjoy. This takes pressure off health services and boosts productivity in the workforce, which has economic benefits.
• Complement existing infrastructure, easing maintenance requirements.
• Mitigate climate change impacts, such as flooding.
• Improve habitat biodiversity, woodland and park cover.
• Improve heat resilience, since green surfaces don’t absorb the sun’s rays and release them as heat, like brick and concrete do.

While the potential exists, nature-based solutions haven’t been developed or delivered at scale.

In part, because of a lack of awareness of the NBS options that exist. As such, we’ve shared some of the existing options below.

Examples of nature-based solutions

1. Constructed wetlands

Put simply, wetlands are areas where water meets land.

From lakes and lagoons to peat bogs and saltmarshes, these ecosystems are homes to a wide variety of species and help to protect us from floods and droughts.

They also help us remove carbon from the atmosphere. According to Wetlands International, peatlands cover 3% of the planet’s surface, but store 30% of all land-based carbon.

Wetlands can also help with pollution control, helping to treat wastewater

But since 1970, over a third of the world’s wetlands have disappeared, mostly due to:

• Pollution;
• climate change;
• invasive species; and
• unsustainable development, where wetlands are drained to make way for housing, industry and agriculture.

Engineers can help restore these habitats – like those who worked on the Marches Mosses BogLIFE project.

Check it out

2. Mangrove restoration

A type of wetland, mangroves are coastal forests made up of the only trees that can thrive in salty water. These purify the water by filtering out nutrients and sediments.

Mangroves grow in tropical and subtropical environments – you can find them in Mexico, Argentina, Brazil, Bangladesh, Malaysia, Papua New Guinea, Gambia, Angola and more.

Indonesia has the most mangroves in the world.

More than 1,500 species rely on mangroves – from herons and crabs to larger mammals like African wild dogs and the so-called ‘fishing cat’.

Mangroves also act as natural carbon sinks, absorbing CO₂ from the atmosphere.

According to the UN Environmental Programme, they store on average 1,000 tonnes of carbon per hectare in their biomass and underlying soils.

They can store this carbon for hundreds of years - if not thousands.

Climate resilience

The trunks and twisty roots of mangroves can absorb the impact of waves, protecting the high ground from coastal erosion, storms, flooding and even tsunamis, by acting as shields.

After the 2004 Indian Ocean tsunami, caused by a 9.1-magnitude undersea earthquake, struck the coasts of Indonesia, research showed that areas covered in coastal forests suffered less damage than those without vegetation.

Globally, a fifth of mangroves have been lost, due to pollution, rising sea levels, coastal development, among other threats. Shrimp farming poses a big risk for mangroves.

Luckily, mangroves can recover naturally, and there are ways to support this process.

3. Habitat restoration

As with the first two examples on this list, restoring habitats to their natural state can be the best path forward.

This could mean reconfiguring or replacing existing structures to allow separate parts of a habitat to reconnect.

It was the approach engineers in Tampa Bay, Florida, USA chose to address a marked decrease in water quality and seagrass in the estuary – where streams, rivers, lakes and storm drains meet the ocean.

The loss of seagrass, essential for marine wildlife including fish and manatees, had been attributed to the construction of the Courtney Campbell causeway in the 1930s.

Traditional stormwater management systems would've required more land to build pipes and artificial ponds.

Instead, engineers chose to replace a section of the embankment with a bridge that would allow the water on either side of the road to interact once again.

This approach significantly improved water quality in the area, with locals reporting clearer water and more wildlife flocking to the area.

It was also the more cost-effective option. Opting for the nature-positive solution led to a USD$100 million saving.

4. Green walls, roofs, alleys, pavements, you name it!

Getting some green on grey infrastructure can have a whole host of benefits.

According to the Royal Horticultural Society, these include:

• Improving storm water management by reducing water run-off
• Providing another layer of insulation for buildings, reducing heating needs
• Offering cooler summers by helping relieve the urban heat island effect
• Providing a home for biodiversity, particularly birds and insects
• Improving air quality
• Reducing noise pollution
• Creating beautiful displays of plants that people can enjoy

Adding some plants to alleys, streets, parking lots and more can go a long way!

Green pavements also incorporate permeable materials that allow rainwater to be absorbed, returning to the soil rather than ending up in the sewer.

5. Bioswales

Bioswales are nature’s own water filtration systems.

They look like shallow channels where polluted stormwater can sit and be purified by vegetation and soil.

They’re placed in long, narrow spaces (like the spot between the pavement and the kerb) and are designed to handle water from areas such as streets and car parks.

They direct the water along a desired path and require a specific blend of special soil, gravel, drains and overflow mechanisms to help manage and purify the water.

6. Rain gardens

Rain gardens are essentially bioswales’ cousins.

They consist of basin-like pits where rainwater is held until it’s absorbed into the ground. They’re meant to handle water run-off from smaller areas such as roofs and driveways.

Covered in plants, rain gardens can be as beautiful as they are functional. They also provide habitats for biodiversity.

Bioswales and rain gardens are techniques often used in sustainable urban drainage systems (SuDS).

7. Living breakwaters

According to the WWF, “well-developed oyster reefs can break up and absorb wave energy protecting coastlines from wave erosion and storm damage”.

Restoring oyster reefs is an NBS solution in its own right, but some engineers have taken this even further and combined these efforts with breakwaters structures.

These are offshore structures, normally made of stone or concrete, that limit wave energy by creating a barrier between open water and the shoreline. They help reduce coastal erosion.

Living breakwaters create an enabling environment for oysters or hard corals to settle.

An award-winning coastal defence system in Staten Island in the US has applied the concept. Aptly named Living Breakwaters, the structure features ridges and grooves that encourage reefs to form.