NbS in Agricultural Use: Potentials of SWB for Erosion Control in Longo Maï, Costa Rica, an interview with Pia Houben

When did you start working at LAND, and how has your experience been?

I started working at LAND one year ago, during my master’s degree in Landscape Architecture and Landscape Planning at BOKU University in Vienna. The first project I worked on was the Machbarkeitsstudie Semmering. Since then, I have had the opportunity to contribute to various urban-scale competitions and conceptual design strategies across Europe. I also took part in the *Botanical Experience in Saudi Arabia* future strategies masterplan.

I really enjoyed my experience at LAND as a student. I felt like I became part of the team very quickly, was given real responsibilities, and received great guidance and support from Amélie, my buddy, and the wider team. It has been a very valuable experience for me, both professionally and personally.

As you are now completing your master’s thesis, could you briefly explain the concept behind it and why it could be important for your collaboration with LAND?

The key concept of my thesis is Nature-Based Solutions in Agricultural Land Use, with a particular focus on the potential of Soil and Water Bioengineering measures for erosion control in the Longo Maï area of Costa Rica.

I believe these topics will become increasingly important, both for our profession and for society as a whole, as we face growing environmental challenges. What I find particularly interesting about Soil and Water Bioengineering is that it combines technical stability with ecological regeneration and long-term resilience, while also supporting local, low-cost, and resource-based approaches.

The Longo Maï area has experienced significant soil erosion as a result of intense rainfall events and agricultural intensification, creating a need for more sustainable approaches to soil and riverbank protection.

The main issue addressed in my thesis is soil erosion, which can become particularly problematic in agricultural landscapes with steep slopes, exposed soil, roads, and monocultures. Erosion can have both on-site impacts, such as soil degradation and loss of fertility, and off-site impacts, such as sediment transport and negative effects on waterways.

My research therefore investigates whether Nature-Based Solutions (NbS) and, more specifically, Soil and Water Bioengineering (SWB) can provide suitable and locally adapted approaches to reducing erosion. These approaches combine living vegetation and local natural materials with engineering principles. Unlike purely technical measures, they aim not only to stabilise soil and reduce erosion, but also to restore ecological functions and increase the long-term resilience of the landscape.

My thesis is structured around two main questions. First, it examines why erosion control is relevant in agricultural landscapes. Second, it investigates whether Nature-Based Solutions and Soil and Water Bioengineering are suitable for reducing soil erosion in Longo Maï, including the challenges and advantages of implementing them and how these measures can be adapted to the local context.

The research also considers the historical and social context of the area, including the interesting community movement that emerged in the 1970s and gave rise to Longo Maï.

Longo Maï is an international network of self-managed agricultural cooperatives and intentional communities operating in Europe and Central America. The community in Costa Rica was established in response to the Nicaraguan dictatorship. It cultivated the land while providing long-term support to refugees from Central American countries such as Nicaragua and El Salvador. Today, the area remains privately owned and is designated as a National Wildlife Refuge.

One of the most inspiring people I met during my research was Don Pedro. He had an incredible amount of knowledge that he had developed simply through years of doing and observing. What struck me was that much of this knowledge had been developed without institutional support.

At the same time, I realised that many people in the community are not necessarily aware of the extent or long-term implications of soil erosion. Through 13 interviews, I found that while there was a general awareness of erosion as an issue, relatively few preventive measures were currently being implemented.

What role can landscape planning play in creating a more equitable future? Are there any design approaches or policies that particularly impressed you during your research?

Working with people on such a small scale, and giving them a central role in the process, allowed me to discover a reality that I had previously known very little about. Since this was an area I had never visited before, it was a great opportunity to actually go to the place I had previously analysed through maps and data.

It gave me the chance to get to know the community and its rural lifestyle. Through the interviews I had the opportunity to conduct, I was able to understand how the farmers of Longo Maï perceive the future of their land, based on their everyday experiences of manual and agricultural work.

This experience made me realise how important it is for landscape planning to connect spatial analysis and design with the people who actually live and work in a landscape. For me, creating a more equitable future means not only designing for people, but also working with them and recognising their knowledge, experience, and role as protagonists in shaping their own environments.

Working at LAND while conducting this research has also strengthened my belief that Nature-based Solutions will play an increasingly important role in the future of landscape architecture, and our cities. In many past projects, I have experienced how difficult it can sometimes be to communicate the importance of these solutions to our clients, even something as simple as the value of planting a tree.

However, I feel that the climate events and environmental changes we have experienced in recent months and years are making these issues increasingly visible and tangible. Perhaps this will finally help more people understand the importance of working with Nature rather than against it.

But our work is far from finished. As landscape architects and designers, we still have an important role to play in demonstrating what Nature-based Solutions can achieve and in making them an integral part of how we plan and design our future landscapes and cities.