Ecological evaluation Urban River Enhancement Scheme Mike Forty Durham University & Ribble Rivers Trust michael.forty@durham.ac.uk

Structure Introduction Methods Results Conclusions Acknowledgements Physical habitat Fish communities Conclusions Acknowledgements

Introduction – Culverts and their impacts Historically built to convey water and pollutants away quicker. Impacts: Low ecological integrity Low complexity of physical habitat Unsuitable hydrological regimes Increase in diffuse and point source pollution Habitat fragmentation Recreational loss to society: disconnect with environment Project Aims: Create areas of more heterogeneous flow, benefitting resident fishes, invertebrates and providing resting places for migratory fish.

Study site – Rivers Calder and Brun

Methods Before-After-Control-Impact (BACI) study design across June-July 2013 - 2015 Annual spatially intensive sampling of: 6 improved treatment sites 11 cobble lined control sites distributed US & DS of treatment reaches 4 unlined control sites, 2 US & 2 DS of town centre Sampling: Fish – 3 pass depletion quantitative surveys Macroinvertebrates – Surber sampling Physical environment – flow-depth profiles

Results – Physical habitat Site Type Site Number Mean width (m) Mean depth (m) Mean velocity (ms-1) 2013 2014 US unlined control 4.45 0.16 0.384 US lined control 1.50 0.20 0.611 Treatment 8 4.30 0.14 0.867 0.351 9 4.93 0.12 0.17 0.942 0.260 DS lined control 1.44 0.832 DS unlined control 7.31 0.18 0.296 Unfinished treatment   1.57 0.15 1.006

Results – Fish presence/absence Site Type Site Number Brown trout Bullhead Stone loach Minnow Stickleback Eel Species Richness 2013 2014 US unlined control 1 ü û 2 3 4 US lined control 5 6 7 Treatment 8 9 DS lined control 10 11 12 13 DS unlined control 14 15 Unfinished treatment 16 17 18   Total Calder fish pass

Results – Fish communities Relative abundance Increase in relative trout abundance between years Highest trout densities found upstream of town centre

Mean densities (fish 100 m-2) Mean fish per unit length Results – Fish communities   Mean densities (fish 100 m-2) Mean fish per unit length 0+:1+ trout ratio Site Type Total trout 0+ trout 1+ trout 2013 2014 US unlined control 64.53 75.82 35.05 44.25 29.48 31.57 2.60 2.85 1.57 1.03 1.28 1.52 1.33 US lined control 36.04 64.35 17.83 15.97 18.21 48.38 0.54 1.17 0.28 0.24 0.26 0.93 5.04 0.25 Treatment 24.44 26.15 20.00 0.47 4.44 25.68 0.37 1.20 0.30 0.02 0.07 1.18 4.33 DS lined control 11.86 23.15 6.61 4.05 5.25 19.10 0.23 0.13 0.10 1.40 0.39 DS unlined control 6.79 8.23 5.38 5.05 1.42 3.18 0.48 0.60 0.38 4.00 1.60 Unfinished treatment 6.99 15.26 3.19 1.08 3.81 14.18 0.06 0.03 0.83 0.11

Results – Fish communities Control Treatment

Conclusions Reprofiling successfully slowed flow velocities and increased heterogeneity in treatment reaches Large changes in fish communities at restored sites Highly mobile individuals first to colonise + suitable habitat High trout densities upstream of town centre should aid in recovery of restored reaches Less mobile species (i.e. bullhead) yet to recolonise treatment reaches Low densities and velocity barriers may potentially slow this process Lack of cover from predation Natural substrate beginning to accumulate May provide cover for smaller fishes aiding their recolonisation Data from 2015 and macroinvertebrate data should provide a clearer picture on the benefits of the works as they begin to recover.

Acknowledgements Dr. Martyn Lucas & Jack Spees Gareth Jones, Paul Peters, Adam Wheeler & all volunteer help All other RRT staff Land owners Environment Agency Heritage Lottery Fund DEFRAs Catchment Restoration Fund