Zora van Leeuwen

Zora van Leeuwen


Woody debris effects on upland river hydromorphological processes

Project overview

Natural accumulations of large wood (>1 m length) in rivers are often associated with physical habitat changes (depth, velocity, organic matter retention) which can have benefits for moderating flow peak timing and magnitude downstream. However, such features are rare because, for centuries, wood has been removed from many rivers to aid navigation and 'improve' flow conveyance. Recommendations for wood management/reintroduction in UK headwater rivers are available from the Environment Agency but these are based largely on lowland river studies. The extent to which these are transferrable to upland localities is unclear given the typically steeper gradients, coarser substrata and flashier flow regimes of upland rivers.

Introducing wood structures and promoting natural accumulations in upland rivers could have benefits for delaying flow peaks to downstream areas via modification of channel morphology. There has so far been very little research in the UK on the effects of wood placement in upland rivers. A more complete understanding of upland river hydromorphological response to woody debris is vital if river managers are to develop more effective restoration and management schemes.


The aim of the project is to develop a quantitative evidence-base of wood-morphology-hydrology interactions in upland rivers.

The central hypothesis to be tested is whether reintroduction of wood into upland rivers will lead to significant changes in river morphology that reduce the magnitude, and delay the timing, of peak flows further downstream.

Research Affiliations


  • NERC CASE studentship
  • 2018 Natural Flood Management Project Officer - Calderdale Metropolitan Borough Council
  • 2013 – 2016 Assistant Engineer – JBA Consulting


  • MEng Civil Engineering, University of Sheffield