Survey will ensure river bank stability in Fenland town centre

A survey of riverbanks is set to be undertaken in a Fenland town centre to ensure desilting works to the waterway do not cause them to slip.

The Middle level Commissioners are in the process of drawing up a programme of works to raise banks along the 190km of waterways they are responsible for managing.

As part of that they are looking at what needs to be done to the River Nene (Old Course) which runs through March town centre amid concerns desilting works could affect the stability of the riverbanks.

In January it was announced the commissioners, who provide flood risk management that protects 8,516 households, 1,643 commercial and industrial properties, over 57,000 hectares of agricultural land, road links, railway lines and a prison in Cambridgeshire, had started a £23m government funded riverbank improvement scheme.

The whole Middle Level system in the Fens is dependent on artificial pumped drainage and river embankments to move excess water from the lowest land in the country into the River Great Ouse via St Germans Pumping Station near King’s Lynn.

To maintain the standard of flood resilience, 136km of river embankment will be improved. Work to the riverbanks will be carried out by removing material from the riverbeds (dredging) and placing it on top and behind the riverbank to raise the existing level. Where there isn’t enough material to reuse, they will import locally sourced material.

In some areas there is not enough room to raise the riverbank with an earth embankment. In these locations we will need to install a hard flood defence such as sheet piles or walls.

In an update on the scheme’s progress the Middle Level Commissioners describe the work as “the most significant programme of works the Middle Level Commissioners have undertaken since the construction of the current St Germans pumping station and is the largest internal drainage board scheme in the Great Ouse catchment.”

They explain they have been focussing on building a project team to plan and develop the scheme ready for construction.

They said: “It requires a dedicated delivery team to manage a scheme of this scale and complexity. This includes ensuring we have undertaken all relevant environmental assessments and approvals carrying out surveys and developing the design.

The Environment Impact Assessment considers all aspects of the works and how it may affect the ecology and environment catchment wide. The first stage of this assessment has been carried out and will be published in local newspapers and online during August and September for stakeholders to comment. All comments will be considered and incorporated into the full assessment for construction.

“As part of this programme, we are assessing what desilting works are required on the River Nene (Old Course) through March Town. Concerns have been raised that the work through March town could affect the stability of the bank.

“We are aware of one bank slip along Nene Parade; however, a further possible bank slip has been identified. To ensure that the desilting work will not make the bank slips worse we will be carrying out a bank survey and stability assessment before programming these works.”

The project is fully funded through Flood Defence Grant-in-Aid (FDGiA) funding from Defra. This funding is from central government for managing flood risk in England providing additional assurance required to ensure value for money is delivered.