NFM volunteering inspired my academic research career path

Hi, my name is Sam Townsend.  I am a final year BSc(Hons) Geography student at the University of Huddersfield and a regular volunteer at Slow The Flow Calderdale (STF). 

Sam Townsend, sampling for macroinvertebrates using a kick-net as part of his dissertation project. (Sam Townsend, 2021)

My final research project for my degree is closely tied to my volunteering. I have been inspired by building leaky woody dams at Crimsworth Dean Beck, Hardcastle Crags with STF, and now, as part of my academic studies, am looking into their effects on macroinvertebrate populations.

In this blog post, I will be sharing my interest in geography and natural flood management (NFM) and how I became involved with Slow The Flow, and considering how I can utilise everything I have learnt from academia and STF for my future career.

Inspired by Geography GCSE

To begin with, where has my enthusiasm for Geography has come from and how that has led me to joining Slow The Flow? What I enjoyed most about Geography compared to my other subjects at secondary school was researching, investigation and report writing. Finding a question, creating a hypothesis and trying to find an answer to explain why something is happening. At that stage of my studies, the Boxing Day 2015 Floods had happened, and that’s where my curiosity for flood management began. 

I continued studying Geography at A Level, where my teacher at Trinity Academy 6th Form, Dr Daniel Whittall, discussed the 2015 Boxing Day Floods and its unprecedented impact on Hebden Bridge. Whilst talking through a number of flood management strategies, he mentioned Slow The Flow’s pilot project; using wood from the Hardcastle Crags Woodland Management scheme as ‘leaky woody dams’, in a natural, soft engineering strategy – creating a healthier woodland, and helping to mitigate flood risk downstream in the Calder Valley.

Volunteers building leaky woody dams at Crimsworth Dean Beck, Hardcastle Crags (Sam Townsend, 2021)

Volunteering to find my passion

At that time, I was seeking volunteer opportunities to broaden my university application, and I thought volunteering for Slow The Flow would be a complementary match for the skills I wanted to develop and be able to demonstrate.

Joining Slow The Flow was very easy; I met the trustees and other volunteers – whether they’re from the local area or professionals from organisations such as the Environment Agency, all come together on alternate Sundays at Hardcastle Crags to make a difference to flood management. 

The National Trust rangers give a tool and safety talk to make sure everybody is comfortable using the equipment. When we arrive at the site for the day, we are split into groups and assigned tasks that suit our abilities, whether that is lifting logs to build dam structures, using loppers to create brash or Himalayan balsam bashing. From being involved in this work on the ground, I knew that I wanted to pursue further study focusing on natural flood management.

Tool and safety  talk from National Trust Rangers (Sam Townsend, 2021)

When applying for university, I wanted to remain local, and the University of Huddersfield had the specialist academics and the modules I wanted to study, including the opportunity to specialise in hydrological sciences and river management. I am pleased to continue working closely with Slow The Flow and helping to educate the local community; for example, I presented a seminar on NFM and the work Slow The Flow do to my old 6th Form. This encouraged some students to volunteer with Slow the Flow, and they have gone into further study with a greater understanding of how effective community groups can be at tackling the problems caused by climate change. 

My dissertation research: leaky dams and tiny creatures

Throughout my time at university, I revolved my studies around natural flood management. Other undergraduate, master and PhD students have already researched the effect that leaky dams have on hydrology, and the effectiveness of natural flood management strategies. While reading through the literature, the research gap I identified was the effect of leaky woody dams on the local ecology. I decided to specifically look at macroinvertebrates (animals lacking a backbone and large enough to see without the aid of a microscope), to which I was introduced by my dissertation supervisor, Dr Tory Milner in a 2nd Year module.

At the time of planning my dissertation, we were in the 2nd national lockdown; however, trustees at Slow the Flow were available to share their advice and with the approval of my dissertation supervisor, I decided on the following research question: The effects of leaky woody dams in ephemeral gullies on aquatic macroinvertebrates and water quality (or, in Plain English: what are some of the additional benefits leaky dams have, as well as helping to reduce flooding?)

To break that question down, I will investigate the effect of leaky woody dams installed by Slow The Flow in gullies, and compare that to a control stream with no leaky woody dams present in the gully. The primary objective of leaky woody dams is to slow down the water moving downstream and redirect it onto the floodplain, which minimises the peak flow and the risk of the river reaching bank full.[1][2] My hypothesis is that this intervention will have a positive impact on macroinvertebrates because of the impact leaky woody dams have on the hydrology; the leaky woody dams can increase the roughness and turbulence. Ecologically, the variability of the hydrological flow regime is widely recognised as one of the primary influences on in-stream biota composition and the leaky woody dams. [3][4][5][6][7] In my research, I will be investigating if the same principles can be applied to the leaky woody dams at Hardcastle Crags.

Research progress to date

To collect the macroinvertebrate samples, I took kick-net samples across a gully with leaky dams, and one without. Water quality and hydrological data were collected at each location. The macroinvertebrate samples were then identified in the lab at the university 60+ hours later and at the time of writing this blog, this is the progress I have made so far (I have still got to analyse the results and write the discussion.)

Macroinvertebrate kick-net sample being sorted at the University of Huddersfield Lab (Sam Townsend, 2021)
Macroinvertebrate kick-net sample being sorted at the University of Huddersfield Lab (Sam Townsend, 2021)

Crystal ball gazing

At the current point in my research (January ’21), here are my predictions: 

  • I would expect to see a difference in the abundance of macroinvertebrates and taxonomic richness, with greater values in the gully with leaky woody dams compared to the control gully (without leaky woody dams). 
  • However, I would expect to see very similar water quality measurements. 

I hope to follow up in a future blog what findings I found in my dissertation.


My time at Slow The Flow, and my time at university, have served to expand my interest in natural flood management, discovered at school in Calderdale. I hope to pursue further academic study and either follow a career path in academia, further researching natural flood management strategies, or potential work in consultancy or a government organisation such as the Environment Agency, specialising in NFM. From my time so far in academia, I firmly believe that nature-based solutions to flood management are just as important to consider as hard engineering strategies – because of the holistic benefits. As well as flood prevention, natural strategies have additional benefits ranging from community awareness – active participation in projects like Slow The Flow, to the wider ecological benefits they have for the environment. 

Volunteers reinforcing a leaky woody dam at Crimsworth Dean Beck, Hardcastle Crags (Sam Townsend, 2021)

Optimism for future students

I am delighted that Slow The Flow has also recruited two education trustees, responsible for overseeing primary, secondary, and higher education resources. As a result, more students, on a local and national scale, will be able to learn about the potential of natural flood management in the classroom and will hopefully be just as inspired as I was to pursue an academic and professional career in this critically important field.

I would like to give a special thanks to the Trustees at Slow The Flow (who are all volunteers), Dr Daniel Whittall and Dr Tory Milner, who have continued to inspire me on this incredible journey in flood management.


[1] Bokhove, O., Kelmanson, M., & Kent, T. (2018). On using flood-excess volume to assess natural flood management, exemplified for extreme 2007 and 2015 floods in Yorkshire.

[2] UK Government. (2021). RP32: Small leaky woody dams. Retrieved from [Accessed 08/10/21]

[3] Deane, A., Norrey, J., Coulthard, E., McKendry, D. C., & Dean, A. P. (2021). Riverine large  woody debris introduced for natural flood management leads to rapid improvement in aquatic macroinvertebrate diversity. Ecological Engineering, 163, 106197. 

[4] Grabowski, R. C., Gurnell, A. M., Burgess‐Gamble, L., England, J., Holland, D., Klaar, M. J., Morrissey, I., Uttley, C., & Wharton, G. (2019). The current state of the use of large wood in river restoration and management. Water and Environment Journal, 33(3), 366-377.

[5] Gurnell, A., England, J., & Burgess‐Gamble, L. (2019). Trees and wood: working with natural river processes. Water and Environment Journal, 33(3), 342-352.

[6] Gurnell, A. M. (2007). Analogies between mineral sediment and vegetative particle dynamics in fluvial systems [Article]. Geomorphology, 89(1-2 SPEC. ISS.), 9-22. 

[7] Krause, S., Klaar, M. J., Hannah, D. M., Mant, J., Bridgeman, J., Trimmer, M., & Manning-Jones, S. (2014). The potential of large woody debris to alter biogeochemical processes and ecosystem services in lowland rivers. Wiley Interdisciplinary Reviews: Water, 1(3), 263-275.