Rural land management impacts on catchment scale flood risk

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source• a link is made to the metadata record in Durham E-Theses• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full Durham E-Theses policy for further details. Most approaches to this problem aim to upscale from individual grid cells to whole catchments, something that restricts the complexity of possible process representation, produces models that may not be parsimonious with the data needed to calibrate them and, faced with data uncertainties, provides computational limitations on the extent to which model uncertainty can be fully explored. Rather than upscaling to problems of concern, this thesis seeks to downscale from locations of known flood risk, as a means of identifying where land use management changes might be beneficial and then uses numerical modelling to identify the kinds of management changes required in those downscaled locations. Thus, the aim of this thesis is to test an approach to understanding the impacts of rural land management upon flood risk based upon catchment-to-source downscaling.This thesis uses the case study of the River Eden catchment (2400 km 2 ) as a test (1) it was shown to have a significant impact on downstream flood risk; and (2) it had range of data and information needed for modelling land use changes.The second part of this thesis explored the land management scenarios that could be used to reduce flood risk at the catchment scale. The scenarios to be tested were determined through a stakeholder participation approach, whereby workshops were held to brainstorm and prioritise land management options, and then to identify specific locations within the Eamont sub-catchment where they could tested. There were two main types of land management scenarios chosen: (1) landscape-scale changes, including afforestation and compaction; and (2) corresponding to a 5.8% decrease in peak discharge. A key conclusion is that land management practices have been shown to have an effect on catchment scale flooding, even for extreme flood events. However, the effect of land management scenarios are both spatially and temporally dependent i.e. the same land management practice has different effects depending on where it is implemented, and when implemented in the same location has different effects on different flood events.

Flood and Traditional Coping Strategy in Ahoada East (2012–2020), Rivers State

“…This study supports the findings of SEPA (2015), which revealed that traditional coping mechanisms include expanding burrow pits and dredging rivers to remove fine sand, clay, and small pieces of rock from the riverbed, which may boost the river's ability to carry water. clearing of obstructed drainages to enable water channelization (Pattison, 2021). This is especially crucial in view of predicted climate change, which indicates that the protective standards we put in place now may not be adequate in the coming decades.…”

“…This is especially crucial in view of predicted climate change, which indicates that the protective standards we put in place now may not be adequate in the coming decades. Planting cover-producing vegetation, such as grass or clover, as opposed to leaving bare soil, prevents soil erosion, preserves soil fertility, and lowers surface runoff (Pattison, 2021).…”