A redundant Carlisle weir could be removed if plans get the green light next week.
An application for full planning permission has been submitted to Cumberland Council by Eden Rivers Trust and it will be discussed by members of the planning committee on Wednesday.
The weir is on the River Pettril, between Adelaide Street and Botcherby Avenue, and its removal aims to improve passage for migratory and non-migratory fish species as well as increasing and improving the habitat for a range of other species.
It has been referred to the committee because the application raises significant issues such that it is in the public interest because of concerns about the impact of the proposals on flooding in the wider area.
Officers have recommended it is approved with conditions.
The planning report said: “Melbourne Park Weir is situated on the River Petteril upstream of Warwick Road in Carlisle.
“The concrete weir structure first appears on the 1960 Ordnance Survey map of the area. It is a straight broad crested structure which has been retrofitted with a fish pass.
“There are sheet piles at the toe of the weir that also require removal as part of the proposed work. The structure impounds around 2m of head on the river causing backing up of water for several hundred metres upstream.
“Flooding around the structure is presently causing erosion on the right bank and this is likely to worsen during future floods.”
According to the report there is an exposed sewer pipe above the weir. It said: “This pipe is currently unsupported for a short length and flood erosion would see this exposure extend under current conditions.
“The sewer is the property of United Utilities who have been informed of the state of the service and no work is proposed to ameliorate the situation as part of this project. The proposed weir removal work would not make the situation any worse.”
A number of options were considered and the report said: “The preferred option for the site – weir removal and morphological enhancement – involves the complete removal of the structure and associated fish pass, minor bed regrading and construction of a pool-riffle sequence linking in with the current developing morphology in the river.
“To help refine the preferred option a model of the study reach has been developed, using available Environment Agency 1m cell size LIDAR, new survey and existing EA hydraulic model information.
“Flow information for the model was developed using existing flows from the EA existing model for this reach and low flows software for the typical summer and winter flow.
“The purpose of the modelling was to appraise the preferred option identified. This enabled assessment of the impacts to in-channel processes and the hydrological regime and iteration of these features to provide the acceptable benefits.
“The model has also assessed the impact on flood risk both locally and downstream through use of a flow monitoring line at the downstream extent of the model.”
Wednesday’s meeting will take place at the Civic Centre in Carlisle from 10.30am.
