Flooding 2001 and Property Insurance
REPORT : FLOODING IN BRIDGE 2001 - property insurance

In early Spring 2001, the River Nailbourne flooded through the valley from Elham to beyond Wickhambreaux where it joins the Little Stour. The rainfall during the autumn and winter of 200/2001 was the heaviest by far since records began in 1766 and for the South Canterbury area the annual rainfall was well over double the average. Nobody can recall flooding from the Nailbourn to anything like the extent of 200/2001.

Properties in the village of Bridge were affected and the Bridge Parish Council joined with all the other parishes along the Nailbourne to form a committee - Little Stour and Nailbourne River Management Group (LSNRMG) to investigate the cause and to bring pressure to bear on the various statutory authorities to ensure corrective action was taken to avoid a re-occurrence. The author of this brief report was a Parish Councillor on Bridge Parish Council and undertook to represent the parish on the LSNRMG.

Initially under the supervision of the City Council and more lately the Environment Agency the whole of the Nailbourne river channel has been inspected and cleaned out. Dredging and removal of any shoals of material and removal of vegetation and debris has also taken place. This has resulted in the capacity of the river channel increasing over and above what existed when it flooded. Other improvements have been made to some of the culverts where there were potential restrictions and Kent Highways has cleaned out to original capacity all road culverts. Since that initial major work after the flooding there has been regular inspection and clearance of the river channel by the Environment Agency.

At the time of the flooding there was a major restriction to the river at the Mill Lane (Bridge Place) footbridge. This caused water to back up and flow into Brewery Lane. This footbridge has been totally renewed by Kent County Council and the flow capacity of the river has been significantly increased. A further general improvement has been made to the highway drainage in the High Street by Kent Highways, which will help to reduce flooding in the village. Two parallel events occurred which affected property insurance :-
a) the government agreed a 10 year moratorium with the insurance companies to not increase rates specifically on properties affected by flooding.
b) The Environment Agency (EA) prepared maps that allegedly indicated the flood zone, in our case those associated with the 2001 events. See Drawing "B ". The Environment Agency has not been able to put a firm return period on the Nailbourne flooding basically because there is nothing at all recorded previously to match it against. The Environment Agency estimate the return frequency flood to be between 1 in 50 and 1 in 200 years.

Now in 2012 the moratorium is about to be lifted and all properties within the flood zones indicated on the Environment Agency maps will face increased insurance premiums. This is linked to postcodes which alert insurers to check the EA maps. There have already been reports of new house purchasers being refused insurance or being asked for high premiums.

The flooding in Bridge in Spring 2001 reached a maximum depth of 300mm near the ford in Mill Lane and in most properties affected, reached no more than 150mm dependent on the ground floor level. Drawing "A" shows the recorded extent of floods in Bridge. The author occupies 90-92 High Street, Bridge and was directly affected. Drawing “A” has not been agreed by all householders shown.

The LSNRMG has met 2/3 times a year since its formation in 2001 and in summary has monitored the following :-
(i) Extensive efforts by the Environment Agency (EA) to clear the Little Stour and parts of the Great Stour of debris, trees and all impediments to the general flow. Dredging has been undertaken for the first time in many years.
(ii) The EA has overseen work by the riparian owners to clear banks etc and maintain a clear channel for the river flows.
(iii) Action by River Stour Internal Drainage Board to similarly ensure open flows.
(iv) To pressure other agencies who have some responsibilities with respect to the River Nailbourne and other water systems or who were caught up in the flooding i.e. Southern Water.
(v) To pressure Southern Water to inspect and repair the main foul drainage system which also runs down the valley and which became water bound and a catalyst for water rising through manholes and causing effluent to become enmeshed with the surface water.

The LSNRMG has been very successful in ensuring removal of many of the 2001 obstacles to the water flows such that the risk of a future "back up" and localised flooding has greatly receded. Southern Water have recently repaired joints in the main sewer substantially reducing surface and ground water ingress into the sewers but have not as yet any responsibility to deal with the ‘laterals’ from this system.

Should there be a similar situation in the future the Environment Agency has now instigated a full flood warning system for the Nailbourne, including Bridge. Because of the nature of the river, which is fed from an aquifer, it will be possible to give a few days notice of probable high flow in the river which will allow residents etc time to take their own precautions against possible flooding – floodboards, sandbags etc.

The conclusions that can be drawn from this ten year exercise is that :-

a) there is a much reduced risk of a future pluvial flood given the same rainfalls
b) the local agencies have a greater knowledge of the possible consequences
c) the local residence have a greater knowledge of cause and effect
d) the planning authority are more vigorous, when granting approval, in asking for scheme that reduce the surface water run off.

Attached to this report are :-
Drawing “A” – contemporary report on actual flooding in Bridge Village. (2001)
Drawing “B” – EA current "Risk of flooding map" (from website 03/2012)
Drawing “C” – an overlay of the risk of flood map onto a detail O.S. map of the centre of Bridge.

Conclusions :

It is clear that the EA map encompasses numerous properties that due to their ground floor datum level were not affected by the 2001 flood, had no claim against any insurance company and are no more at risk now than in 2001. Given the extensive work by LSNRMG with all agencies, the ability of the River Nailbourne, the Little Stour and to some extent the Great Stour to cater more successfully with any increase water flows is assured and will be monitored in the future.

Thanks to:- Ted Edwards Senior Drainage Engineer. Canterbury City Council and Jill Thomas, Secretary LSNRMG

Mervyn Gulvin RIBA - March 2012

Printable Report on Flooding in Bridge in 2001

Drawing A – contemporary report on actual flooding in Bridge Village (2001)

Drawing B - Environment Agency current "Risk of flooding map" (from website 03/2012)

Drawing C - an overlay of the risk of flood map onto a detail O.S. map of the centre of Bridge