Fish Ladder Design a Great Success

Scotland has long-harnessed water energy through weirs and other structures. Although power is now largely sourced from other industries, many of the weirs still remain, preventing fish species such as salmon from migrating upstream to their natural spawning areas.

Two abandoned weirs on the Avon Water in South Lanarkshire – Ferniegair and Millgheugh – were identified by the Rivers and Fisheries Trust of Scotland as particularly obstructive to fish, as they close off large areas of riverbed

Following a feasibility study carried out by design and project management consultants WS Atkins Ltd, the preferred option for opening up these inaccessible areas to spawning fish was through the construction of fish ladders

Conservation and enhancement of native freshwater fish and their environments in Scotland

RAFTS – Rivers And Fisheries Trusts Of Scotland


BlockWall was approached by WS Atkins and supported the design process working out ways that the blocks could be anchored to the riverbed. Ducts where cast into the blocks at 800mm centers to allow the blocks to be bonded together and anchored to the river bed rock. 25mm rebar was used as the reinforcement and was grouted in with a non shrinkable grout.

Blockwalls was chosen to supply its Stackabloc 1.6m x 0.8m x 0.8m x 2.5 tonne heavy duty interlocking wall blocks to form the fish ladders. The blocks needed to blend with the clay riverbed and, after a series of trials, Hanson Colourcrete in Straw was specified as the best match.

The civil engineering contractor was George Leslie Ltd of Glasgow. George Leslie were ideal to execute this project from the impressive civil engineering experience. Blockwalls worked closely with George Leslie to ensure the right blocks were delivered at the right time for site production. Access to the site was created by laying a stone road along the riverbed that was removed on completion of the works.

The 480 tonne of interlocking blocks have been used to great effect to create the new fish ladders, which have resulted in around 200 kilometres of river being opened up to spawning fish

Blockwalls supported WS Atkins and George Leslie with 3D design drawing to see how the blocks worked and for the team to visualise the project. If you have a project and you think concrete interlocking blocks can be used, then make contact. We are very friendly and love a challenge.

The project was designed by WS Atkins


Working in partnership with structural engineers and civil engineering contractors.

We come from the civil engineering sector and have invested in the development of advanced concrete technology and quality assurance. Our mission is to support structural engineers and civil engineering contractor to come up with innovative solutions to common problems. Block Walls are the ideal solution for structural engineers and civil contractors who are seeking cost effective solutions to properly manage their projects.


You send us a basic description or drawing of the area you need to construct and a description of the operation. We will do the rest.


1. Our design team will establish which specification will best fit your environment and calculate the number of blocks required to do the job

2. We quote, you order, we make

3. We deliver


SolutionsWe offer a full design service from simply working out how many blocks you require for your project to full design including drawings and calculations.

Our full design service can include:

  • Planning applications
  • Structural engineering design and calculations
  • 2D and 3D CAD drawings and BIM models
  • Building regulation applications
  • Full project management services

The main contractor was George Leslie from Glasgow

CALL 0800 880 3135

Call today and tell us about your project. We can then design it and give you the quantities of blocks you require together with a quotation. We supply all the method and risk assessments and COSHH data sheets for installation. Opening hours from 9am to 5pm Monday to Friday (except bank holidays).

INTERLOCKING CONCRETE BLOCKS Material, Scrap, Recycling, Silage Bays Call 0800 880 3135 CONSTRUCTION Blast Walls, Bund Walls, Fire Walls, Buildings Call 0800 880 3135 MARITIME Dock, Breakwater, Quay, Harbour Walls Call 0800 880 3135 CIVIL ENGINEERING Retaining Walls, Piling Mats, Temporary Works Call 0800 880 3135

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