FAQs

Dredging in the Environment Agency means removing accumulated material in the river like gravel or soil (often referred to as silt) that has been washed into rivers from somewhere else, as well as rocks and plant life.   Other maintenance activities such as in-channel weed clearance, blockage removal and vegetation management are also important to maintain the conveyance of channels.

There is an important distinction between dredging and desilting. Dredging is a bigger exercise and is used infrequently to remove consolidated material to below the existing bed level. We desilt more frequently to remove recent deposits of silt to the bed level of a river. 

We assess each situation individually and dredge when it is the right solution, and it provides long-term value for money. Understanding where it will, and will not, reduce flood risk is key. 

Dredging can, and does, contribute to reducing flooding in some locations and each situation is individually assessed. Where there is evidence that dredging will reduce flood risk to local properties without increasing flooding downstream, it meets government criteria, and is cost effective, we will do it.  

In some locations and circumstances, dredging would not be an efficient or effective way to manage flood risk. Therefore, it is not the best long term or economic solution compared with other flood risk measures such as building walls or providing storage upstream. Any structures in the river such as bridges and natural features need to be considered, as these pinch points can make dredging ineffective.  

Please see the official guidance on gov.uk - Calculate GiA funding for FCERM projects.

A hydraulic model is a collection of mathematical equations that give a simple representation of reality. They estimate flow, water level and velocity in river channels. pipe networks. tidal systems.

Hydraulic modelling was undertaken on Mill Dam Dyke in 2020, the results of this modelling was used in 2023 when the EA commissioned an Optioneering Assessment Exercise and Report for Mill Dam Dyke.

The Optioneering Exercise looked at several potential engineering interventions for Mill Dam Dyke and they are summarised in the Report.

As part of the exercise siltation scenarios on the Mill Dam Dyke were run and included in the assessment. This showed that siltation has no significant change in flood extent. The Hydraulic Modelling undertaken in 2020 shows no silt in Mill Dam Dyke until the section where is joins the Fleet and then it is at a low level.

Overtopping:

The modelling shows that the main area that Mill Dam Dyke may overtop is at the corner of School Lane and Chapel Lane which is the start of the Environment Agency Embankment. There was no evidence of overtopping here during the winter of 2023/24.

At no other point does the right bank, and therefore the embankment, overtop. This is due to the left side of Mill Dam Dyke (Non-Environment Agency Asset) always being at a lower elevation, encouraging the watercourse to flood the local agricultural land to the left.

It should also be noted that Mill Dam Dyke overtops adjacent to Swinderby Road in several places when the channel becomes constrained by a bridge (private or 3^rd party asset) running across the channel. There is also evidence of this on Chapel Lane (private access bridge). It should be noted that properties in Swinderby Road and Chapel Lane do not sit behind Environment Agency Defences (see overview of assets document under Asset Management on this page).

A number of options were looked at and these can be reviewed by reading the report, which can be found in the Optioneering Assessment Report (see Asset Management documents in this page). 

The Optioneering Assessment found that many sections of the Embankment are above a 1 in 100-year return period. The final recommendation from the assessment shows that any portion of the embankment that was above this level could be removed without impacting flood risk to the stakeholders in the area.

Please note that this will not happen without consultation and would be subject to the EA being able secure the level of funding which would be required.

Reducing the height of the embankment would reduce the steepness of the embankments and allow maintenance to be undertaken in a more efficient manner.

In the East Midlands, the Environment Agency has undertaken a strategic review of the area, to identify those communities most at risk and to identify where the most benefits can be gained from investment of flood defence grant in aid, as well as exploring partnership opportunities with our professional partners and communities. The Environment Agency reviews the investment programme regularly to take account of new flooding information and data, and partnership funding opportunities.

Unfortunately, there is not currently a project on the investment programme for the area of North Scarle and it is unlikely that an economically viable project would be able to be developed in this area.

Our climate is changing, sea levels are rising, and we are experiencing more extreme weather. 

We are already seeing these changes: 2022 was the warmest year on record in the UK. In July 2022 recorded temperatures exceeded 40C for the first time in the UK. 

Long term records show that in the UK: 

• temperatures are rising. 
• more rainfall in winter is falling in heavy events. 
• sea levels are rising more rapidly than in the past. 

The scale of potential future flooding and coastal change is significant. One in 6 people are already at risk of flooding from rivers and the sea. The risks will only increase with rising sea levels, more frequent and severe floods, and storm surges. 

Surface water flooding generally occurs in urban areas when water cannot drain away or soak into the ground. It can happen very quickly and is difficult to predict.   

Lead local flood authorities (LLFAs), which are unitary or county councils, have the principal role for managing the risk of flooding from surface water in their area. This includes understanding the risk and planning to manage it.  

The Environment Agency has a strategic overview role for all sources of flooding, which includes surface water. Through this role, we show strategic leadership by playing an active role in supporting local authorities and other partners in enabling them to plan and adapt to current and future surface water flood risk.  

Anyone can check their risk from surface water flooding: Check the long term flood risk for an area in England - GOV.UK (www.gov.uk)