Overview
The River Kensey flows through Launceston and on to the River Tamar.
Low lying areas of Launceston, such as Newport, are susceptible to fluvial (river) flooding. Whilst higher levels of the town may suffer from issues due to surface water runoff.
Review of historic flooding
The River Kensey has caused widespread flooding to the Newport area of Launceston. Flooding has also been caused by the Wooda Stream which is culverted prior to flowing into the River Kensey. The Lowley Brook, which drains the town south of the A30 has caused flooding to rural properties.
Rivers and catchments
The River Kensey runs from west to east through Launceston. Low lying parts of the town are susceptible to flooding from it.
The Wooda Stream drains from the north side of the A30, from Chapel and through St Thomas in to Launceston. Whilst the Roydon Stream drains southward through Newport to the River Kensey.
North of the A30 drainage is to the River Kensey and on to the Tamar. South of the A30 water drains to the Lowley Brook and then on to the River Tamar. Activities to the south of the A30 therefore do not affect flood Risk in Launceston.
Risk of flooding from rivers
Around 285 properties are at risk of fluvial (river) flooding in Launceston. Of which around 215 are residential and 70 are commercial. Including a school and an electricity sub-station.
Risk of flooding from surface water
Over 420 properties are potentially at risk from surface water flooding. Of these around 315 are residential properties and over 100 properties are commercial including a school and a nursing home.
Flood risk management in Launceston
In 1984 a scheme was implemented at Newport. It involved:
- increasing the flow capacity under the bridge
- improving the channel to reduce water levels
- the construction of a small defence across the bottom of West Bridge Road
The scheme was designed to a 40-year return period. Flooding may therefore be expected in defended areas during a 1:100 year event.
The main urban areas of Launceston are categorised as a Critical Drainage Area (CDA). Any development which occurs in a CDA requires a reduction in flood risk (betterment) rather than requiring a neutral impact
Launceston sits within Policy Area 3 of the Central Tamar area of the Tamar Catchment Flood Management Plan. Policy Area 3 is categorised as “Areas of low to moderate flood risk where we are generally managing flood risk effectively”.
Main challenges for local flood risk management in Launceston
The main issue with flood risk management in Launceston is that it is situated within the flood plain of the River Kensey. Upstream of the confluences of the River Kensey and Tamar.
As the town sits within the floodplain, mitigation of flood risk will have to rely on upper catchment work, or major disruption in the urban areas.
Opportunities for flood risk management in Launceston
- Investigate the potential of upstream storage areas in the River Kensey catchment.
- Maintain existing channels and guard against blockages.
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Properties alongside the River Kensey may benefit from Property Flood Resilence measures.