At Longham Lakes Water Treatment Works in Ferndown, we recently converted a decommissioned groundwater pump storage building into a purpose-built multi-seasonal bat roost.
From pump house to wildlife refuge
Originally constructed around 1982, the building was once part of a system that collected groundwater and pumped it to the local water treatment works, so it could be treated and put into supply. After being decommissioned, the structure, containing switchgear machinery and a below ground pump room, was identified as a potential site to support the local bat population.
In January 2025, planning permission was granted by Dorset Council to repurpose the building into a multi-seasonal bat roost - a safe, sheltered space where bats can rest, hibernate, and raise their young.
Understanding the structure
A bat roost can be natural or man-made, offering refuge to wildlife during colder months or periods of rest. Natural examples include caves and tree hollows, while artificial examples have been found in old buildings, mines, or specially designed structures like the roost at Longham Lakes.
Before construction began, we worked with EAD Ecology to carry out extensive bat surveys. While no bats were found roosting inside the original building, the surrounding area showed high levels of bat activity, including species such as common, soprano, and Nathusius pipistrelles, Myotis species, and noctule bats.
Building for biodiversity
To bring the roost to life, we partnered with Ebro Solutions Ltd. The project involved:
• Removing the existing internal infrastructure and roofing panels
• Repairing and reinforcing the existing structure
• Installing a suspended floor to create different temperature zones and hanging space for roosting bats
• Constructing two new gable roofs using bat-friendly materials to enable bats to be fly around inside before emerging
External features for Bat roosting
• Bat tiles: Specially modified roof tiles provide crevice-dwelling bats with safe entry points.
• Integrated bat boxes: Built into the gable ends to attract cavity-roosting species.
• Dormer access: Designed for horseshoe bats, which prefer to fly directly into their roosts.
Internal design for comfort and safety
• Baffles: Overlapping structures that block light and create secluded draft free spaces for maternity roosts.
• Suspended floor with hatch: Allows internal bat access to both cool and warm zones, ideal for multi-seasonal use.
Meet the prospective residents
The UK is home to 18 bat species, 17 of which breed here. All are insectivores and play a vital role in controlling insect populations. From the tiny pipistrelle to the impressive greater horseshoe, each species has unique roosting and foraging habits.
Bats use a variety of habitats throughout the year, including:
• Woodlands and hedgerows for roosting and foraging
• Waterways and lakes for hydration and foraging
• Buildings - like our new multi-seasonal bat roost - for shelter and breeding
Protected and respected
All UK bat species are protected by law under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017. This means it’s illegal to harm bats or disturb their roosts, even if bats aren’t present at the time.
By creating this multi-seasonal bat roost, Bournemouth Water is not only supporting local biodiversity, but also ensuring compliance with conservation legislation and contributing to the long-term survival of these fascinating creatures.
Update 1 - October 2025
Such careful design has clearly paid off because, despite only being completed in April this year, the new roost has already been occupied by soprano pipistrelle bats, which are using the integral the wall boxes.
Photo Credits © PMcNie, taken under NE License (2017-27297-CLS-CLS).
For more information about this project, please email biodiversity@southwestwater.co.uk