An underwater crack in a concrete wall between a river and a trout farm is sealed in a repair made using Sylmasta AB Original Epoxy Putty

Environment Agency Repair Crack in Underwater Wall Between River & Trout Farm

The UK Environment Agency repair a 700mm long crack in an underwater wall, through which water was escaping from a river to a trout farm and causing issues with the monitoring of extraction being made within permitted levels.

Case Study Overview

Site Sluice between river and trout farm
Location Yorkshire, United Kingdom
Repair Type Underwater repair
Products Sylmasta AB Original Epoxy Putty


Trout farms in North Yorkshire, England, can draw a limited amount of water from rivers and streams. Extraction is controlled by a sluice connecting a farm to a river and levels are monitored by the Environment Agency to ensure no more than the permitted amount of water is taken.

Anomalies with data from one farm alerted the Environment Agency to an issue. Initially, they believed there to be a problem with the sluice or the recording equipment. An inspection however revealed a 700mm long crack in a concrete wall next to the sluice.

Water from the river was escaping from the river to the farm through the crack, making readings of flow through the sluice totally inaccurate.

The crack needed to be sealed to prevent water loss and establish the true level of water being extracted by the farm was within the rules.

SylWrap Solution

With the majority of the crack below the waterline, the Environment Agency approved the use of Sylmasta AB Original Epoxy Putty for the repair because of its ability to cure underwater and bond with wet surfaces.

The Putty was mixed in dry conditions. Once it had turned a uniform white colour and whilst it still remained soft, it was pushed into the crack. The application began above the waterline, working down to the riverbed where the crack became a sizable hole at its widest point.

AB Original easily adhered to the concrete. After two hours, the Putty had cured to form a rock-hard, waterproof material permanently filling the crack. Water levels were then carefully checked, showing a very small leak remained.

This was identified as being near the riverbed, where mud and silt had made it impossible to tell if the entire crack had been filled. The Environment Agency carried out a second visit where further AB Original was applied at the base of the wall.

An underwater crack in a wall undergoes repair by the Environment Agency using Sylmasta AB Original Epoxy Putty
The entire length of the crack both above and below water was sealed with Sylmasta AB Original Epoxy Putty


Extraction from the river to the farm returned to expected levels after the second visit, indicating that the crack had now been successfully sealed by AB Original.

The repair ensured that the trout farm was not inadvertently receiving more water than allowed from the river via the crack, enabling both the farm and the Environment Agency to see that extraction remained within the permitted limits.

Follow Up

Given the challenging nature of underwater repair, the Environment Agency were pleased to have discovered such a versatile material capable of being effective underwater. They have since begun using AB Original for other applications and projects in challenging environments.

Products Used

AB Original Epoxy Putty
Epoxy putty which bonds and cures underwater, sealing holes and cracks in most substrates

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