Following my initial Advisory Visit on 8th December 2010 we were finally allowed to get our wellies on and make some habitat improvements to a stream in the Wigan area (close to where I partially mis-spent my youth!). So in March 2013 an intrepid band of local volunteers were led by Paul Kenyon, whose house backs onto the river, to participate in a WTT Trout in the Town habitat Practical Visit. We were also joined by local landowner Ian Parker who got firmly stuck into the labour – and is interested in additional works on his section of river just upstream.
The presence of a few wild trout in the reach shows the potential of this river – although it is currently periodically struck by serious pollution incidents that have emanated from a Victorian-era dye works upstream as well as Combined Sewer Outfall discharges. The provision of improved habitat in this reach is hoped to provide opportunities for generations of fish to thrive and reproduce in-between pollution incidents on the main river. It will also act to improve the resilience of fish populations using the (non-polluted) tributaries to spawn by improving survival prospects for juvenile and young adult fish. In this way, the abilities of fish to repopulate following catastrophe are boosted.
The irony that the “day to day” water quality is easily good enough to support trout is evidenced by the rapid-recolonisation of various “pollution-sensitive” invertebrate species living there – as well as the presence of trout above the offending periodic pollution inputs. The potential to invest in increasing the capacity of storm overflow tanks on the Combined Sewer system has been raised by the Environment Agency – and would be a very welcome and highly appropriate development. We hope that the presence of the wild, pollution-sensitive, trout AND the improved habitat will give us great leverage to seek the improvements necessary to protect against pollution from all sources. The occasional foul water event is the only thing standing in the way of a really thriving wild river.
The main thrust of the habitat works was to increase the complexity of the habitat by introducing and securely anchoring the crowns of trees into the river margins at alternating intervals. This would provide both an increase in the physical “shelter” habitat from predation and spate flows; but also introduce a degree of variety in the current speeds across the river’s cross-section. Both types of increased complexity are at a premium in river channels that have been historically straightened and locked in place with reinforced banks (such as this one).
Drilling a hole in a tree trunk using a petrol auger (so that the steel cable can be threaded through and attached to its anchor-point)
A Tirfor winch can be used as a cheap alternative to heavy plant machinery hire to position trees
Some judicious steering and cajoling of an awkward trunk can be required!
Paul (K) and Paul (G) apply the fasteners to the steel anchor cable - which is kept as short as possible
Where's my stick?
Where do you want this one?
Well-earned post-match refreshment :)