4. Outcome

2. Prioritisation strategy

3. Fish passage measures undertaken

• One weir removal

• Two eel ramps

• One partial weir removal

• One multi-species fish pass at most downstream structure in the catchment

1. Background

• River Worfe catchment: • Sub-catchment of the River Severn; • 150 km length watercourse; • Eight of nine of its waterbodies failing WFD due to urban/rural pollution, fish habitat/aquatic quality, invasive species, and fish passage.

• Over 70 potential barriers to migration identified in the River Worfe catchment during previous APEM habitat walkover for the River Worfe

Restoration Project.

• Severn Rivers Trust sought to provide passage at as many of the structures as possible on a limited: • budget (ca £100,000); and • timescale (ca. nine months).

• Eel passage focus due to budget and timescale constraints.

• A prioritisation strategy applied to give the ‘biggest bang for the buck’, involving:

1. Identify 25 structures for detailed passage assessments and course resolution options appraisals; 2. Feasibility studies and fish pass options appraisal of 10 of the original 25 sites; 3. Design and delivery of fish passage facilities at as many of the 10 sites as possible.

Figure 1. Barriers to migration on the Worfe catchment.

Step 1: Identified 25 priority sites based on:

• Location in catchment; • Distance upstream; • Length of upstream watercourse; • Main stem / tributary.

• Likely hindrance to fish; • High level rating from original

walkover; • Fish pass team rating from images.

Figure 2. Location of barriers assessed for passability.

Step 2: Identified 10 sites for feasibility and options appraisal based on:

• Step 1 criteria; and

• Step 1 assessment, including likely cost and ease of eel pass provision.

Figure 3. Location of barriers for feasibility

and options appraisal.

Step 3: Design and delivery of passage facilities at as many sites as possible.

Undertook detailed design and gained Environment Agency approval of six sites , BUT:

• A parallel running crayfish survey identified that two of the structures had mixed signal and white clawed crayfish populations downstream, but only white clawed present upstream, therefore passage not provided as would facilitate crayfish upstream movement;

• Landowner at one site sadly passed away, therefore site put on hold.

• THEREFORE detailed design and approval for two additional sites was undertaken / gained. Figure 4. Location of

mitigation measures undertaken.

BEFORE AFTER

Figure 6. Partial weir removal: weir board removed as no existing function, monitoring undertaken to ensure no impact on habitat (e.g. bank destabilisation).

BEFORE AFTER

Figure 5. Full weir removal.

ALBRIGHTON

GRINDLE

INSTALLATION AT ALBRIGHTON

Figure 7. Eel ramps installed.

5. Lessons learned • It is possible to provide a number of simple eel

/ fish passes in a relatively short time period; • Can’t predict every scenario;

• Must be adaptable • Be realistic of what is achievable;

• E.g. not feasible to spend entire budget on one large technical pass

• Plan for the future.

BEFORE

AFTER

Figure 8. ‘Low cost baffles’ & eel tile cassettes on a Crump weir gauging station.

Provision of fish passage in the Worfe catchment

Dr Iain Stewart-Russon (i.stewart-russon@apemltd.co.uk) APEM Ltd