Key lessons:
The implementation of the suite of 35 NWRM features within the Belford Burn has shown how a catchment plan was created that was effective at providing multi purpose benefits (including flooding prevention and water quality improvements). A variety of stakeholders were engaged in the work from identification of the problem to be addressed to the siting and implementation of the individual NWRMs. A challenge is to remain adaptable and flexible, changing materials or NWRMs used to suit specific site conditions, in some cases using existing natural features within the channel such as large boulders, trees and bends to assist with stream control without the need for in-channel structures. Although developed for Belford the approach has generic applicability to many other catchments. Key lessons identified are that:
- A number of NWRMs can be used together, with the materials, location and choice of feature being dependant on local factors including land owner/farmer preferences and local terrain.
- One single NWRM feature only has a small benefit and it is likely that a number may be required together, but this should not ignore the fact that other structural measures may also be beneficial.
- Online features are best suited to smaller channels.
- The effectiveness of networks of NWRMs to attenuate flood depends upon the shape of the hydrograph, often being more effective for flashy short duration flood events.
- Ongoing maintenance and the potential need to recover trapped sediment, which could be of value to famers.
- It is essential to engage stakeholders, as this will encourage uptake by farmers.
- It is crucial to build up the trust of farmers and residents from the earliest opportunity and maintain it throughout.
One important finding has been that different types of measures may be more effective for flood and water quality benefits. At this site, a range of measures has been incorporated in to the overall scheme and hence provides effectiveness for both flood management and water quality improvements (nutrients and sediment). However only using a single type of measure, rather than a range, may not have been so successful in this regard. The need to consider a range of measures distributed through the catchment, to meet multiple objectives, is clear.