November 2022 - August 2023 The National Trust

FiveRivers was commissioned by the National Trust to perform a fish rescue operation at the water gardens at Cliveden. The water gardens consist of two interlinked ponds with floating water lilies, supporting an array of aquatic life including ornamental and course fish. Recently, cracks in the ponds concrete foundations have caused a steady leak requiring a regular top up of water.

Following the isolation and damming of each pond, FiveRivers caught and transferred fish from each pond in turn. Following the safe removal of fish, contractors were then able to proceed with dewatering and desilting each pond before repairing any cracks within the foundation.

Project requirements

The problem

FiveRivers required clear communication with the staff at the National Trust and the pond contractors to ensure the greatest efficiency and timely repairs to the ponds, allowing the water gardens to be reopened to the public as quickly as possible.

As the ponds had not been emptied in 30 years, the fish rescue team had to be prepared to deal with unforeseen circumstances and the possibility of large quantities of fish. A high level of preparation and client engagement was essential to preform the task to a high standard.


Our approach

The solution

FiveRivers completed two site visits to Cliveden water gardens. The first visit cleared the main pond of all fish, allowing repair works to begin. The following visit relocated fish from the adjacent pond, delivering the client’s desire for all fish to be located in the first repaired pond.

An experienced team of fisheries ecologists used a combined method of seine netting and electrofishing to catch and translocate fish from each pond.

All fish were measured, identified and underwent a health check before being returned to the water garden.

Project outcomes

The results

A total of 1,748 fish were caught and relocated from the ponds, consisting of rudd, koi carp, common carp and mirror carp. Fish specimens were found between 20mm and 650mm. To help control the population in the pond and maintain fish welfare, a number of the fish were humanely euthanised.

FiveRivers offered a further service by assisting the National Trust team in selecting suitable marginal and emergent plant species to encourage the biodiversity of the water garden.

Fish were successfully removed from both ponds to allow their de-silting and essential repairs to the concrete foundations. A healthy and sustainable number of fish were safely returned to the original pond which had been cleaned and resealed.

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Callum and the team were A1! Before, during and after the works I found Five Rivers very professional and accommodating to specific needs. Thank you very much.
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