10/03/2021
Response from Environment Agency
Thank you for your enquiry which was received on 4/2/21. Please accept my apologies for the delay.
I enclose our officer’s comments below:
‘Following a meeting with the Head Green-keeper at Flixton Golf Club on Monday 1st March we surveyed the eastern section of the golf course where the photographs indicated overtopping river flows and flow path into the grounds, see attachment. Water had entered the course and from the photographs it is evident that this highest recorded flood event on the R. Mersey has reached a level which overtops the high ground at the eastern extreme of the site as shown by the flows passing under the barbed wire fence line, see photo 1 and 2.
Flood Risk
It was noted that properties on Snowden Drive No 91 -109 are built at a lower level than the majority of the elevated street pattern see phot 3 reference. Flows from the extreme Mersey event filled the drainage ditch at the rear of the properties and spread out across the course reaching the third party embankments located in the centre of the course and close to the club house. No properties were damaged in the floods but residents would have witnessed a wide spread filling of the flood plain with levels approaching boundary walls possibly garage structures at the peak of this highest recorded flow.
Recommendation – to include the evidence collected and feed into river modelling and the forthcoming Mersey South Manchester Strategy looking at the sustainable management of the river and its assets into the future and the approach to climate change.
Erosion of the Mersey banks
The golf course eastern end sits alongside the Mersey on the right-bank it is immediately downstream of an incise meander and will naturally receive the fastest flows during an event located as it is on the outer curve of the river. This has post-event washed bank material and exposed unconsolidated brick amongst the soil on the river slopes. Previous attempts at willow embankment toe reinforcement is evident. However a large willow is present at the river toe this has caught significant tree trunks in flow event and this structure is possibly contributing to further erosion during high flows as they are diverted by the tree/blockage material see photo 4. There are signs of ground cracking at the bank top and conditions for more material to slump with loss of riverside land at the wash out location.
Recommendation – following some constructive discussions on site it was recommended that the landowner looks to utilise the available willow material and re-establish or increase the linear length of willow spilling erosion control or similar bio-engineered solution. However with readily available material willow spilling can create a stable toe of living material behind which seeded soil can revegetate. Some land loss is inevitable following the event but developing a vegetated reduced gradient offers a sustainable solution. The following link from Gov.uk site advises on an exemption to carry out this type of work https://www.gov.uk/government/publications/environmental-permitting-regulations-exempt-flood-risk-activities/exempt-flood-risk-activities-environmental-permits -and-protecting-up-to-10m-of-main-river-banks-using-natural-materials-fra13. We would be happy to discuss any plans you have in-line with this or other approaches which may require permits to undertake depending on the construction type and extent.
The single in-channel willow could be removed to reduce flow and erosion on the right-bank, we again would provide advice and if required inspection of the tree prior to any removal, please note tree removal would be prohibited between March and September.’
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