This site is designed as a source of information for the Flood Warden and Volunteers, the Cerne Valley Parish Council and also for the residents of Cerne Abbas, Dorset, UK who wish to check the current Flood Status, find out about how to protect their properties still further and clarify what their own responsibilities are to protect their own and other people's property.
About
Flood Plan - Introduction
Plan Revision History: Jan 2007,
Revised and extended February 2011, June 2011, Sept 2011
Site last updated April 2024
The aim of this Flood Plan is to mitigate and manage any flooding in Cerne Abbas. It makes reference to the organisation put in place by the Environment Agency (EA) to anticipate potential flooding, the roles of local authorities, and the roles of Cerne Valley Parish Council and its appointed Flood Warden. The Plan also emphasises that whilst steps can be taken to manage a flood, the responsibilities of certain residents, riparian owners and local landowners to act pro-actively is seen as key to reducing both the causes and effects of flooding.
The current Voluntary Flood Warden
and author of this site is Andrew Popkin
Flooding in Cerne Abbas
The River Cerne is largely a groundwater fed river with a small upstream catchment, running mainly over Chalk and Upper Greensand. The bed armour material is mainly local flints and remains stable. This is often overlain by shifting seasonal banks of sandy silt with a healthy ecosystem of flora and fauna. Due to surface run-off and at times of high groundwater levels, the river level may rise or appear coloured.
Flood Storage Area
Cerne Abbas benefits from a Category 'A' Flood Attenuation or storage Reservoir with a dam built across the valley to the north of the village.
The reservoir is designed to hold approximately 68,000 m3 of flood water over 2.18 km2 and release it slowly through a control structure known as a penstock, beneath the dam. The height of the penstock is set and fixed but is locally adjustable in an emergency using hydraulic equipment, operated from a control position on the dam. There is an incident room at the Blandford EA depot which is equipped with monitors receiving live images from cctv cameras in our area which includes that from our own installation here in Cerne. Telemetry data is also gathered on site by way of water height sensors at several points in the river and this too, is sent to the control centre. Thus controlled, the river maintains a maximum height and flow rate through Cerne Abbas and beyond downstream, in times of heavy rainfall.
Secondary defence scheme.
Surface water from unusually heavy rain may run into the village from the surrounding hillsides at times of high levels of groundwater. Normally, this water runs into the gullies and culverts under Long Street and thence into the River Cerne. In exceptional cases, the water may be in excess of what the culverts and gullies are designed to cope with, possibly exacerbated by their becoming blocked with leaves or field debris washed down. This excess water is then captured effectively by a large steel U shaped grating across the street, and fed into the 1.2m wide pre-cast flood relief culvert. This culvert follows the most direct route to the River Cerne downstream of the village. All culverts are remotely inspected and cleansed regularly on behalf of the council. These assets are maintained by the Dorset Council.
This site is about:
Cerne Abbas Flood Plan.
Check the current Cerne Abbas flood warning or alert status.
How to protect your property.
What to do before a flood.
How to be prepared.
What to do after a Flood.
Cerne Abbas, Dorset.