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This publication is available at https://www.gov.uk/government/publications/river-lavant-flood-alleviation-scheme/river-lavant-flood-alleviation-scheme
The River Lavant flood alleviation scheme is designed to reduce the risk of flooding in Chichester and the surrounding areas, whilst not increasing risk elsewhere. It works by carrying flood water from the River Lavant at Chichester out to the sea, at Pagham Harbour.
The River Lavant is a chalk stream that typically only flows during winter when groundwater levels are high. In its lower reaches it flows through Chichester to the sea near Fishbourne.
The river is an open channel for much of its course, but is contained within two long culverts (pipes) beneath the city. In extreme conditions, when the capacity of the culverts is exceeded, serious flooding can occur.
How the scheme works
The scheme was built by the Environment Agency, and is designed to be operated in a phased way in response to rising water levels in the River Lavant.
Phase 1 involves lowering water levels in Church Farm Pit and East Pit, to the east of Chichester, by adjusting sluice gates. This creates additional capacity to store flood water that is diverted into the pits.
Phase 2 involves diverting some of the water from the River Lavant into the pits. Once the pits are full, flood water will then flow down the route of the alleviation scheme to the outfall structures at Pagham Harbour.
The scheme has been carefully designed to ensure that no property next to the Forebridge and Pagham Rifes is at any increased risk of flooding as a result of the scheme being operated.
Latest update: January 2014
The Environment Agency has started Phase 2 of the River Lavant flood alleviation scheme.
For more information, email: SSDEnquiries@environment-agency.gov.uk