Resilience and adaptation of muddy flooding mitigation to climate change

Abstract

Soil erosion by water from arable land poses a serious threat to on-field agricultural productivity and the wider environment through off-site damage. Muddy flooding is a symptom of soil erosion by water that is commonly reported across the European Loess Belt. Several arable locations in Flanders, Belgium demonstrate success in mitigating muddy flooding under current climatic conditions by combining a range of curative measures with sensible farming practices. However, multiple studies show that climate change will worsen the impacts muddy flooding in various regions – it is unlikely that existing mitigation measures to control muddy flooding will remain effective in future. This thesis examines how muddy flooding mitigation measures can be adapted to make them more resilient to future climate change for a heavily impacted catchment in Limburg, Belgium.

This thesis adopts a modelling approach to generate a range of likely site-specific muddy flooding scenarios during 2021-2100. A novel and comprehensive methodology is followed to select suitable climate models, which in turn were spatially and temporally downscaled to generate site-specific, daily resolution future climate change scenarios. A continuous simulation soil erosion model – WEPP – was simulated to generate soil erosion projections along four hillslopes under each climate scenario during 2021-2100. A separate event-based soil erosion model – Erosion3D – was simulated to illustrate spatial patterns of erosion across the catchment during 2021-2100. The impact of a range of likely land use choices on soil erosion was also examined. Potential mitigation strategies were stress-tested to future climatic conditions using WEPP and Erosion3D. Mitigation strategies were first shortlisted based on efficacy to mitigate soil erosion to current rates or below under each climatic future, followed by further shortlisting based on farmer practicability.

Results confirm that the magnitude of erosion will begin to increase considerably between 2041-2100 with existing land management, while a longer muddy flooding season is projected. The frequency of high magnitude events will also drastically increase. Conservation tillage represents the most favourable strategy for farmers to effectively mitigate erosion during 2021-2040, followed by practising no tillage that will be effective up to 2061-2080. Mixing summer crops with winter wheat in vulnerable fields will also be a highly effective strategy during 2021-2080. Banning summer crops within vulnerable fields will be the only strategy that is effective during 2081-2100. As an analogue for other impacted catchments, these findings must be communicated. Several short and long-term research needs must be addressed to fine-tune model projections. Data availability – especially long-term field-based measurements of muddy floods – continues to limit soil erosion modelling, while effective education on muddy flooding problems and solutions is urgently needed.

Thesis is embargoed until 31 July 2026.

Date of Award	Jul 2023
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Donal Mullan (Supervisor) & Jennifer McKinley (Supervisor)