Leaky Dams

Leaky Dams

In the UK, small leaky woody dams have become a common flood control practice (focusing on attenuation benefits). In fact, Natural England offers stweardship grants (See RP32: Small Leaky Woody Dams) of £401 to £500 per dam per year. 'Leaky Dam's are another example of inexpensive, low-tech, instream structures designed to emulate specific natural processes. With these flavor of structures, some practitioners and designers have a tendency to focus a little heavilly on 'stability' of the structure itself. This is presumably because implicitly it is assumed that structure failure would be a bad thing, but in natural systems woody debris jam 'failures' and beaver dam 'blowouts' are often associated with some of the most diverse habitats and most desireable features. That said, in systems that have ample sediment supplies, such 'leaky dams' can be good at promoting structually forced riffle_ (Wheaton et al. 2015).

A fact-sheet from Yorkshire Dales River Trust on Leaky Dams.

https://www.therrc.co.uk/MOT/References/WT_Managing_woody_debris.pdf

References

Leaky Dams

Related Structures & Concepts

  • DeVries P, Fetherston KL, Vitale A and Madsen S. 2012. Emulating Riverine Landscape Controls of Beaver in Stream Restoration. Fisheries. 37(6): 246-255. DOI: 10.1080/03632415.2012.687263. - These ‘low walls’ are very similar to the ‘leaky dams’ .

DevriesFig5

Figure 5 from DeVries et al (2012) showing ‘log wall’, ‘engneered-flow choke’ structures similar to the ‘leaky dams’, intended to ‘emulate effects of beaver dam’.

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