PROJECT
SUMMARY
Gotter Water is a tributary of the River Gryffe, which flows through the Quarriers Village development situated between Kilmacolm and Bridge of Weir in Renfrewshire.
THE DETAIL
The 19th century Victorian concrete weir which had formed a pooled water supply for the original estate’s fire-engine has presented a barrier to upstream fish migration effectively preventing access to 9km of excellent upstream spawning habitat for salmon, sea trout and other migratory river species which have been in evidence immediately downstream of the weir.
The objective of these works was to create passage for migratory fish and involved:
- Re-establishing the overgrown river-banks
- Re-grading the river-bed sediment
- Cutting a 2m wide ‘notch’ in the existing weir and installing a steel baffle-plate nose cone
- Constructing new, downstream pools with ‘notched’ mini weirs and wing walls
OUTCOME
Almost immediately upon completion, salmon were observed migrating upstream, across the new weirs and ladder ponds – with the new structure performing exactly as had been intended.
CHALLENGES
- Restricted site access
- Confined working area
- Rapid fluctuations in river flow conditions
- Environmentally sensitive riverbed working
- Close liaison with adjacent residents to coordinate site movements
