PhD Project – Gabby Powell


Biography: I am a first year Environmental Science PhD candidate at the University of Reading. I completed my Bachelor’s degree in Human and Physical Geography at the University of Reading in 2019, with my dissertation topic focussing on the sustainable management of urban greenspaces, looking at the effect of leaf litter management on tree soil properties. In my free time I enjoy running and baking (much to the pleasure of the other postgraduates in the office).

Project outline: NFM is the reduction of flood risk by protecting, restoring, altering, and emulating natural river catchment features.  NFM, part of working with natural processes (WWNP), has clear environmental benefits in comparison to its less sustainable, hard engineering alternatives. It can also be initially cheaper and is an integrated element of the landscape, interconnected with both the social and natural sciences.  This study will focus on leaky barriers and woodlands (tree-planting) as forms of NFM along with community engagement.

Leaky barriers slow the flow of water immediately upstream, improving vertical and lateral connectivity to the floodplain and groundwater. This discourages incision of watercourses, which heightens downstream flood risk as discharge is greater.  Arguably, there are 3 kinds of leaky barrier: natural (a tree has fallen), semi-natural (tree trunks and branches are cut and positioned to look natural), and structured (purposefully engineered). However, the evidence base to support NFM measures is variable, and particularly gaps exist on how effective different measures are in lowland groundwater dominated catchments compared to upland surface water dominated catchments where most research has been carried out to date.

Additionally, it is an integral part of NFM to incorporate local knowledge into NFM measures as this encourages a bottom-up approach to flood management. Community engagement encapsulates this; it is a participatory method where the public have an input in changing their environment as opposed to a top-down approach.

My research focusses on 2 locations within lowland groundwater dominated catchments, fed by chalk streams in the West Thames area:

1) River Bourne, Englefield, Berkshire: Pang Valley Flood Forum (PVFF) selected this location based on the underlying geology of the catchment as it is a flashy watercourse which feeds into the River Pang

2) River Whitewater, Mill Corner, Hook: Chalk streams running through gardens and private property, with additional sewer flooding

Working in partnership with Thames Water, TWENTY65, Hart District Council, Pang Valley Flood Forum, Forest Research


  • Evaluate the impact of woody leaky barriers on peak flow using field monitoring data
  • Evaluate the impact of woodlands on infiltration and soil water storage
  • Assess the role of community engagement and knowledge in NFM project design, delivery, and monitoring


My project overview poster which was presented at the annual LANDWISE conference in February 2020.





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