Bucks council responds to increased flood risks due to climate change
Over the past few years Transport for Buckinghamshire (TfB) has been developing a new two-pronged approach to flood management in response to increasing heavy rainfalls attributed to climate change.
TFBs Network Improvement Team developed a matrix to prioritise proposed drainage schemes and the flood management team also advised on flood risk areas in order to tackle flooding before it becomes an issue to residents.
Alongside this, highway maintenance teams carry out a range of activities including routine gully clearing to keep the drainage flowing.
The matrix is completed to score each proposed scheme against a set of criteria which includes road safety, property damage, local reports and time weighting. From this matrix a rolling programme of works is developed with approximately 30 schemes prioritised for delivery each year.
Scientists say that as the world has warmed by 0.7C, the atmosphere is able to hold 4% more moisture, resulting in more rain.
Persistent wet weather started in mid-August 2019 and continued throughout the latter part of the year, with a series of downpours in late November bringing one of the wettest weeks in the last 50 years and causing major disruption.
A local resident of Eastern Dene gave feedback on the new scheme which was completed in December: "It is really reassuring to know that you are continuing with strategies to relieve the flooding issue in our area. With the heavy rain on Thursday, the drains between Eastern Dene and Park Lane worked well and the new drains by the new catch pit coped with the water before it entered the road."
Often problems lie within underground drainage pipes, or more recently the issue of a lot of water trying to enter the drainage at once, overwhelming the system, and gullies and pipes can also become blocked with debris, especially during autumn leaf fall.
To help with this an additional machine was brought in by TfB for a twelve week period in order to supplement the efforts of the three full time teams in the depots in the North and South of the County.
Existing gully machines have also been upgraded, operating from the depots at Aylesbury, High Wycombe and Amersham. This will double the number of gully emptiers active on the network between April and June, combating the effects of the winter period and preparing the network for the autumn and winter weather of 2020/21.
To maximise efficiency, a new asset management software system (GullySMART) is now in use to manage over 79,000 gullies in Buckinghamshire. The system combines mobile technology with mapping data, building a forward looking profile of required maintenance.
Mark Shaw Deputy Leader and Cabinet Member for Transportation keeps a keen eye on all work in progress to manage flooding and said: "I am satisfied that this two pronged approach to gully clearing plus major schemes to address the more problem areas of highway flooding will have a significant impact however, we can’t get complacent. I am pleased that we will also be adding an additional £1 million to the routine gully clearing programme from April 2020. We will have an extra 3 gully machines on the network between April and June giving us 6 machines to get ahead of ourselves this year, should we experience another wet autumn."
There are big swings in rainfall from year to year, but the overall trend is upwards since 1960. Last year, for instance, extreme rain fell around once every 70 days.