Public Park Desilt

Stonbury were contracted to carry out desilting works to an ornamental lake at a public park. The works required; a ‘Flood Risk Activities’ permit, pollution control and regular monitoring.

Working closely with the client and the Environment Agency, a method of works was agreed and the relevant permit was applied for, to allow the works to be completed. Temporary pollution control measures were then installed downstream of the lake to avoid any silt or oils entering the watercourse.

Regular monitoring was required to ensure the works were not impacting the watercourse and the quality of the water. This was done at a monitoring point located further downstream and involved several checks each day.

The flow from the river was redirected into the lakes natural bypass channel using the existing penstocks, which maintained the flow downstream. However, a pump was also on standby to support the flow where required.

Once the lake had drained down to a suitable level, an excavator was used to install a section of timber posts around an extension to the existing island. The void was then filled with small branches and vegetation to create a containment bund for the silt removed from the lake bed.

The silt was dredged using a 13T excavator and was cast into the newly built bund. Once the bund reached capacity, the lake was refilled in a controlled manner to prevent silt getting washed downstream.

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