Wind erosion

Background

Soil erosion by wind is a natural process that is significantly influenced by the anthropogenic use of land, such as agricultural cultivation, and has a major impact on soil functions. Particularly when there is a lack of soil cover, which is often caused by agricultural use, the fine, usually most fertile soil components such as silt, clay minerals, humus and plant nutrients are removed by the wind and lost from the area. The coarser and humus-poor soil particles remain, which further reduces soil fertility.

By modelling wind erosion with different scenarios and the possibility of evaluating these comparatively via a WebGIS platform, the client or the project working group can determine the susceptibility of certain regions in Germany to wind erosion. As a result, detailed analyses can be carried out to identify particularly vulnerable areas and plan suitable measures.

Challenge

In order to understand natural processes such as wind erosion in high resolution, very large data sets such as the digital surface model (DSM) with a resolution of 1 metre had to be processed throughout Germany and high-performance algorithms developed to derive the protective effect of wind obstacles. It was necessary for the joint working group to be able to provide transparent technical support throughout the project.

Solution

Algorithm development with OpenCV
Data integration and ETL processes
Automated calculation workflow
Evaluation and presentation in stoffeintraege-more.de

Implementation

As part of the nationwide project on wind erosion modelling in accordance with DIN 19706, special emphasis was placed on the development of an automated process ranging from data integration to the provision of results in a WebGIS application, in addition to technical implementation. The working group was able to continuously analyse and evaluate the work status via protected access. At the end of the project, the results were made available to the interested public on the website stoffeintraege-more.de.

The risk of erosion due to wind was calculated nationwide at a 10-metre resolution. A complex workflow was developed for this, in which various data sets were processed, including

Wind speeds and directions from the German Weather Service (DWD)
Soil data from the pedological overview map (BÜK 200)
Soil data from the pedological overview map (BÜK 200)
Digital terrain model (DTM) with 10 metre resolution
Digital surface model (DSM) with 1 metre resolution

The development of algorithms to derive the protective effect of wind obstacles posed a particular challenge. These algorithms had to be precise enough to correctly map the effects of landscape elements such as hedges, rows of trees and other structural elements on wind distribution and thus on the risk of erosion.

The modelling results were subjected to post-processing in order to be able to carry out descriptive statistical evaluations at different spatial levels in real time. This made it possible to carry out detailed analyses and assessments of erosion risks at different administrative and natural spatial levels.

During the project period, the Federal Environment Agency was transparently involved as the client by making the work statuses available on the WebGIS platform stoffeintraege-more.de with password protection. This platform offered extensive search, filter and export options that facilitated the evaluation of the modelling results. The data aggregations could be carried out at different spatial levels, which enabled the results to be analysed flexibly and in detail.

Der Nutzen

The results of wind erosion modelling are an important data basis for the activities of the planned National Monitoring Centre. They are to be incorporated into reporting and the associated modelling and forecasts of changes in soil condition. They are also an important building block when recommendations for action to protect the soil from degradation are developed and designed.