1. Ecological evaluation Urban River Enhancement Scheme
Mike Forty
Durham University & Ribble Rivers Trust

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

3. 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.

4. Study site – Rivers Calder and Brun

5. Methods
Before-After-Control-Impact (BACI) study design across June-July
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

6. 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

7. 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

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

9. 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

10. Results – Fish communities
Control
Treatment

11. 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.

12. 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