Blogs Highways Highlight

Flooding at Rectory Hill was an ongoing issue and concern for local Members and residents for months, following heavy rainfall last year. Under the railway bridge frequently became a flooding hotspot after downpours, causing disruption for motorists such as long delays and vehicle breakdowns and road closures.

Following multiple surveys and investigation works carried out by our teams, we were able to identify the root causes of the persistent problem – and start to design an appropriate scheme to deal with the situation! It was believed that the flooding was due to damage to the drainage system following work by a third-party contractor some years ago.

The main challenge of this scheme was the topography which means the arrangement of the natural and constructed features on the surface of an area, for example its hills, rivers, buildings, and roads. The solution included going further up Rectory Hill, away from the bridge, and down the footpath between the neighbouring woods and the third-party's compound. Here, the team determined the best solution was to use “horizontal drilling” - an innovative trenchless tunneling technique to reduce persistent and recurring flooding issues.

The horizontal drilling technique saw 49 metres of pipework installed, diverting rainwater away from under the railway bridge on Rectory Hill to an existing outfall (the discharge point of a waste stream into a body of water). The technique was utilised to avoid substantial excavation and trenching in a heavily wooded conservation area.

This was the first time Buckinghamshire Highways used this technique. The first step involved some temporary works to dig a hole in the ground to reach the depth of the defective drainage pipe. A horizontal boring machine (a large machine which digs holes in a horizontal direction) was then brought in, creating a tunnel from the carriageway, underneath the path, and through to its final destination, a chamber in the low point of the footpath. The benefit of horizontal boring is that this technique enables teams to bore more quickly than traditional construction methods at this depth. It also requires less reinstatement and repairs of the carriageway and footway, as the work is underground. This also protects any major tree routes and utilities assets.

The scheme has been delivered on budget, and its successful completion marks a significant milestone in Buckinghamshire Council’s capital drainage programme as the flooding underneath the railway bridge has been an ongoing source of concern and disruption for local residents.

During this programme of works, the site also benefited from the use of an Eco Pod welfare van. When compared to traditional generator-powered welfare vans, this has a huge carbon savings of 7.3 tonnes (the equivalent of charging approx. 888,000 smart phones!*) per week, or approximately 44.3 tonnes throughout the scheme's 6-week delivery (equivalent to the energy use for a whole year of 5.9 homes)** contributing to our commitment to reduce our carbon footprint.

*1 Tonne of CO2: What Does it Look Like? | CrownOil

**Greenhouse Gas Equivalencies Calculator | United States Environmental Protection Agency

Fortunately, discussions on the matter enabled the council to reach a settlement that protected our council taxpaying residents from the costs of rectifying the issues and putting in a permanent solution.

The road has now reopened after repair work on the drainage system was completed in February 2025.