MSc Hydrology student Nick Roos reports on erosion in Bonaire

12 August 2017

The island of Bonaire suffers from the effects of soil erosion. To determine possible solutions, Master' student Nick Roos is currently examining the causes of this erosion around the capital of Kralendijk. Other students from the VU and UvA will continue the measurements in the coming years.

On Bonaire, special municipality of the Netherlands, erosion is a serious problem. In areas with sparse vegetation, intense rainfall events (such as those occurring on Bonaire) can loosen the soil material, after which it is transported away towards the ocean by (rain)water flowing over the surface. This not only causes a loss of fertile soil, it also has consequences for aquatic life and plants along the coast, such as the coral reef system. The erosion consequently also affects tourism in the area.

Causes of erosion

Erosion of soil can be influenced by many factors, such as the infiltration rate of the soil and the vegetation cover. Human activities, such as deforestation, overgrazing by goats, and urbanization affect these factors, and thus the erosion. A low capacity of the urban drainage system and poor spatial planning compound these effects.

Master' student Nick Roos investigating the soil around Kralendijk. Photo: Nick Roos

Collaboration

The Vrije Universiteit (VU) and Universiteit van Amsterdam (UvA) are teaming up with partners from Bonaire (Wayak√° Advies BV) to do research into these erosion issues. Nick Roos, an MSc Hydrology student at the VU, currently examines the causes of erosion by determining the most important soil and hydrologic characteristics of different land types around the capital of Kralendijk.

For instance, measures in the area of Salina di Vlijt show a layer of deposited soil of up to 50 cm. This is fertile soil that flowed from higher areas into the Salina during heavy rainfall and is testimony to the magnitude of the erosion issues in the area. Using these measurements, Nick will develop a hotspot map indicating which areas probably contribute most to the erosion.

Layers of deposited soil around Kralendijk made visible. Photo: Nick Roos

Reduce erosion

The research project is a first effort to determine where action could be taken to reduce erosion and gives input for the type of measure that may be suited for such an area. Over the next two years, more students from Amsterdam will go to Bonaire to investigate concrete measures to reduce erosion.

The Dutch Caribbean Nature Alliance is interested in the results from this project and featured the research in their Newsletter:

Written in collaboration with Nick Roos

Published by  IBED Water