Clearance and repair to reduce flood risk: local authority guidance

8. Case Studies

8.1 Erosion not flood risk

Following a burn in spate in the Highlands severe erosion occurred adjacent to houses where the burn edge and training walls had been eroded, see Photo 1.

Members of the Council suggested to the landowner that the Council would take measures of repair/reinstatement, but following assessment it was clear that the erosion and the associated downstream movement of sediment did not cause a substantial flood risk, and as such the Council had no duty and no works were undertaken by the Council. It is of note that further downstream the erosion impacted on the local road and measures to remove sediment and stabilise the road were undertaken under the Road Scotland Act duties.

8.2 Low capacity culvert

In the Highlands a number of houses abutting a watercourse had been developed and over the years the watercourse had been culverted by the developers in a piecemeal fashion. Following nearby tree felling operations water flow down the watercourse increased significantly causing flooding. An assessment and investigations including trial pitting to establish the as constructed details were undertaken and sediment removed and pipes repaired under the Council's duties of clearance and repair. Following discussions with forestry owner, measures were taken by the landowner to redirect and attenuate the flow from the upstream land. The local residents were unhappy to realise that the culvert had such little capacity. The Council, whilst having no duty to increase the capacity offered to upsize the culvert as long as agreement with all affected parties could be reached. Such agreement was not granted and the improvement offer was subsequently withdrawn. This issue was referred to the Ombudsman and the Council position was upheld.

8.3 Watercourse assessment and desk top studies

The Highland Council was alerted to a flood, in part, resulting from a blocked culvert under the road, the flood resulted in damage to a property drive causing washout. The Council had undertaken a desktop assessment of the watercourse and deemed it low risk and no site inspection was required. Following the flood the council undertook site inspections and the culvert was cleaned out, but the flood damage was not repaired. It was apparent that the culvert was of insufficient size to carry flood flows. Following several complaints and referral to the Ombudsman the issues being that the Council failed to investigate the drainage problems and failed to alleviate or remove as reasonably practical the risk of flooding, the Ombudsman found the actions of the Council to be reasonable, and that the additional flood assessment following the flood was an appropriate response. He said ' I cannot comment on the classification of the burn in 2013 as low risk. This decision appears to have been reached on the basis of a baseline inspection, which is the process we would expect the council to follow. I note the burn is now being inspected on a more frequent basis now that it has actually flooded…In terms of whether the council failed to alleviate or remove, as far as is reasonably practical the risk of flooding, I am satisfied that the council's main duty here was in formulating Flood Strategies and Plans. You have not provided evidence that the council failed to act in accordance with that duty.'

CASE STUDY

Level of flood risk

Angus Council has a principle that where an assessment has identified locations where less than 2 properties are affected by flooding that no works of clearance and repair will be scheduled.