Last Thursday I accompanied Tim Jacklin on an advisory visit to Cheshire's "Eaton Flyfishers" water on the River Dane. This is a stretch of rural river (rather than a Trout in the Town stretch) - but I was looking to learn from Tim's wealth of experience in general habitat restoration. The potential benefit of this would be two-fold; firstly for expanding my own knowledge and secondly for me to explore potential translations of rural restoration techniques into urban counterparts. On our visit we found a lovely, well featured stretch of river that formed an interesting riffle-pool series with a nice variety of light and shade. It was particularly gratifying to see a good selection of large woody debris (LWD) that had been allowed to remain in the channel. The cover and bed scouring provided by LWD is of huge importance to the trout and is often sadly lacking in many river reaches. The influence of such debris on the flow characteristics also provides some much needed variety in slower pools; which is of benefit to invertebrate diversity as well as improving fish habitat. Americans attach the label "lunker structure" to fallen tree debris so its presence should be welcomed by anglers. Eaton Flyfishers have not made the mistake of removing this vital habitat from their river (apart from one colossal dam that formed across the full channel during recent monster floods).
Whilst the river Dane is fortunate to have a natural periodic input (and retention) of LWD, urban rivers may not be so lucky. But, subject to satisfying flood risk concerns, there is still opportunity to deliberately pin suitable trees and logs into the stream bed in urban reaches. If such pinning is done with appropriate consideration, river bed scour can be concentrated within the existing channel (rather than towards the bank). Bed scour within the channel would promote holding "pot" formation in the stream bed as well as enhancing the cleaning and sorting of gravel that may be suitable for spawning. Focussing scour away from the banks avoids inappropriately accelerated bank erosion that could cause problems in either rural or urban streams.
So wherever your club holds fishing on rivers (whether urban or rural); don't be in a hurry to haul fallen trees out of the river during working parties. That could well lead to the best fish in your reach sidling away to pastures new in search of another lunker lair.