MNV was contracted by the Tweed Forum to deliver a river restoration project in Northumberland.
The project looked at flooding issues on the River Till, focusing on damage caused by an increasing frequency and intensity of flood events around the Till – Glen confluence.
This problem is not new. Flood embankments, ditches, swales and sluices designed to protect agricultural land have been in place in this location since 1866, but despite this a devastating 2008 flood marked the start of a series of catastrophic events resulting in crop and livestock losses.
It now seems possible that the existing flood mitigation infrastructure may be preventing floodwater from spilling out onto the natural floodplain, with a resulting loss of natural wetland habitat and exacerbation of downstream flooding problems. Existing embankments are also failing to protect important agricultural land from the frequency and increasing magnitude of local flooding.
The project assessed flooding issues and proposed short-term mitigation measures for land and livestock protection while increasing habitat diversity and reducing local and downstream flooding impacts.
The site is around the confluence of the Rivers Till and Glen, bounded by two farms, both of which have been affected by recent flooding due to overtopping and breaching of existing flood embankments. Hundreds of sheep were lost, fences damaged and up to 20 square km of cropland and fields affected by scouring, deposition and waterlogging.
Land use is mixed across the project area; with low-lying fields left as grassland and some grazing, while further back from the river the land is dominated by arable fields and improved grassland. Floodbanks to the east of the confluence protect a key area of arable land.
Rising at an altitude of 630 meteres on the south side of The Cheviot, the Till starts life as the River Breamish, changing name as it flows north then north east as one of the main tributaries of the River Tweed, finally joining the Tweed 4 km downstream from Coldstream after draining an area of around 670 km2.
From the project site to the Tweed confluence, the river is very meandering and relatively slow moving, cutting down through glacial sand and gravel and with scores of abandoned meanders and river features across the erodible floodplain.
The study looked at flooding, land use, embankment management, habitat creation and protection and provided guidance to farmers on land management options. The configuration, suitability, and appropriateness of existing floodbanks were reassessed.
Vital considerations for the project were to prevent proposed works leading to an increase in flood risk to other properties or land, to improve the current situation for farmers and the environment.
