DIG Article for HNews Winter Issue

Pumping Station Ditches and Culverts

During September Jerry Morley and Paul Woodford met with Chris King of Affinity in connection with the drainage issue we have at the pumping station at Hughenden Valley. Chris is a Surveyor with responsibilities for maintenance of infrastructure at Affinity properties.

Chris has agreed to organise a complete site survey at the pumping station, which will involve CCTV checks and, if appropriate, clearance on the two principal culverts under the site which carry the Hughenden stream. It will also involve checking boundaries and cutting back of trees and hedges which have become overgrown.

As a group the DIG are not convinced that these two culverts have sufficient capacity to keep the stream flowing properly when it is in spate. We have seen at least one instance in the last few years of the water in the Valley Road ditch coming right up to the top and threatening to flood onto the road. A simple solution would be for TfB to continue the ditch right along in front of the pumping station so that it could then empty round the perimeter fence of the site into the National Trust field.

Sewer Works in the Valley

One of the biggest problems with the Hughenden Valley sewage system is the ingress of water into the system that typically happens over the winter period. This is common in the country and happens with old infrastructure.

Fractures in pipes and inspection pit brickwork allow ground water to enter the system, whilst road surface water can enter through leaky inspection pit covers. Thames Water have stated in the past that under normal conditions, the sewers in our area run at about 40% of capacity. During a wet winter we know from bitter experience this can exceed 100%, causing spillages.

In the last issue of the magazine, we mentioned that Thames Water was carrying out work on sealing the covers to the sewage inspection pits along Warrendene. Further work was done in the same area in relation to the possible re-lining of the sewer.

This work was of an investigatory nature and Thames Water are seeking to identify leaky areas in our sewage system so that a reactive leak reduction plan can be implemented.

Interestingly, the re-lining of sewage pipes is an established process which can have a major benefit to leaky sewers. Effectively, it is a structural ‘No-Dig’ repair which creates a new pipe within a damaged sewer. A resin impregnated liner is inverted into a defective pipe, it is then pressurised and then cured to form a new pipe. We hope this work comes to pass.

Paul Woodford