Netherton Burn Runoff Management
Elilaw Farm, Netherton, Coquet Valley
This project has been a partnership approach with input from the landowner, Cheviot Futures, the PROACTIVE team at Newcastle University, Northumberland Community Flooding Partnership, the local community and Catchment Sensitive Farming.
Using the expertise and experience gained by the PROACTIVE team on a natural flood management project on the Belford Burn, Cheviot Futures has led the development and implementation of this similar initiative on the Netherton Burn.
The Netherton Burn is a tributary of the Wreigh Burn, in turn part of the wider Coquet catchment. There have been flooding issues in previous flood events in the downstream village of Netherton, largely linked to issues of water backing up at a road culvert and spilling out onto the main road in the village.
This project has seen the development and implementation of a series of runoff attenuation or natural flood management features on the Netherton Burn as it flows through the farm holding of Elilaw.
The first phase of works was completed between January and March 2012 and comprised the following features:
- Farm pond with additional storage capacity for flood waters in times of high flow. This pond also incorporates a series of sediment traps which will settle out varying grades of sediment material ahead of reaching the main pond; stripping out nutrients to reduce the diffuse pollution risk, and maximising the storage capacity and lifespan of the main pond feature.
- Floodplain bunds to maximise the natural storage capacity of the floodplain upstream of the pond. Material from the pond was stored on site and then used to build two bund features, which will hold back water and store it on the floodplain during high flow events, releasing it slowly back to the system via pipes. The slow release will allow the main peak flow to move through the system ahead of the store water finding its way back to the main watercourse.
- Ditch bund to divert high flows into the floodplain storage feature, rather than directly to the Netherton burn. This allows sediments and nutrients to be dropped out of water from farm drainage systems and also reduces the peak flow to the main watercourse. The bund has an integrated pipe and sluice drop-board to allow normal flows to pass through the pipe unhindered, and only back up and divert the higher flows.
The second phase of works has been completed in October - November 2012 and has involved the creation of a swale feature to capture water from the Netherton Burn itself in high flow situations.
The swale has been designed in such a way as to only come into play at a point when the Netherton Burn would begin to spill out of bank. In this way it is of most benefit to reducing flood risk downstream.
Water from the Burn will spill down the swale, and then be diverted by the ditch bund into the floodplain storage area, thereby connecting the top features together in a high flow event. The swale will, in time, re-vegetate and largely disappear into the landscape.
The work at Elilaw has been carried out to a high standard by local contractors who as a result will be well placed to advise on similar works elsewhere in future:
- WA Graham & Co, Newton, Harbottle, Northumberland
- WL Straughan & Son Ltd, Lane Farm, Bedlington, Northumberland
This project is an example of how natural flood management can be integrated with wider farm management without negative impact, as well as assisting with the management of diffuse pollution risk and creating new habitat for wildlife.
The farm has now secured a Higher Level Stewardship agreement with Natural England, largely as a result of engaging with this work. This agreement will assist the management and maintenance of these features going forward beyond the lifetime of Cheviot Futures.