Projects/River Warden Updates – Ivel & Flit
We have continued to increase the number of stretches covered by volunteers and now cover many of the accessible parts of the Ivel, Flit and Hit in our area.
Fallen trees, eroding banks, dense aquatic vegetation growth and very low flows are the main issues reported by wardens.
Sometimes fallen trees can be left (secured in some cases) in situ to create in channel variation, shade, temperature and flow variations behaving as naturally occurring river restoration structures. Such features can be seen in the Ivel at The Riddy, Sandy and Biggleswade Common. Some of these are being monitored using fixed point photography.
The restoration works at Gamlingay and Biggleswade continue to be monitored by fixed point photography and invertebrate sampling and we are still looking to extend these activities to the wider catchment if anyone would like to get involved please do get in touch with Richard.
A large section of bank erosion at Flitwick Moor is putting the public footpath at risk from partially collapsing into the River Flit. The Wildlife Trust has scoped a project to prevent further erosion and collapsing of the riverbank that is currently in very close proximity to the footpath, a public right of way. The bank is a vertical cliff suffering from undercutting erosion, more so during flood and high flow events, and is only a couple of metres from the footpath. Discussions have been held with all stakeholders of the area, agreeing a way forward and a suitable remediation plan. The aim would be to deliver the project in the drier and lower flow summer months.
–Richard Lawrence (Bedfordshire Rural Communities Charity) (Flit comment, Lewis Dickinson WTBCN)
The current volunteering activities are building on the work of BRCC staff and volunteers in the Ivel catchment over the last 25 years, having spread out wardening from initially just the Millbridge/ Potton Brook we are now covering parts of a number of the tributaries of the Ivel and some of the Ivel itself. Some baselines are still to be completed but please do continue to undertake your monitoring visits and fill in the online forms. We are looking to cover as much of the catchment as possible.
Several areas have been noted by wardens as suffering from worsening erosion, mainly due to cattle and dogs gaining access to the river and in some places this is leading to damage to footpaths. This has led to some projects being developed with Central Bedfordshire Council to stabilise and restore the banks and once these have been finalised and consented we will be putting out an appeal for help to actually undertake the practical works installing brash bundles into the river.
In addition to monitoring walks some volunteers have undertaken a wide range of river improvement works, particularly at Gamlingay and Biggleswade and these continue to be monitored by wardens, fixed point photography and by invertebrate sampling. This is currently being targeted at sections where we have undertaken works in the past but we would like to expand it to the wider catchment. If either fixed point photography or invertebrate sampling is something that you would like to get involved in please do get in touch.
The Gamlingay works were undertaken on a nearly straight section of steep banked water way (The Millbridge Brook). The channel was suffering from siltation, being choked by weeds and there were some areas where over steep banks were collapsing. With permission from the Bedford Group of Internal Drainage Group volunteers cleared a central channel through dense vegetation, installed brash bundles to protect the banks and narrow the channel in over-wide sections of channel and installed log to act as flow deflectors to give more flow diversity. A pile of brash was installed to divert flow into a back channel to add a more naturally sinuous form to the channel. These features seem to have been a great success with a clear gravelly bed now being evident in places and there is a greater diversity in flow features such as fast moving water and small , still pools. Continued monitoring will hopefully show that these works have improved the invertebrate diversity here too.
At Biggleswade a number of works were undertaken in partnership with the Environment Agency. This included some heavy machinery being brought in to re-profile rapidly eroding banks to draw them away from the river to reduce the likelihood of further material entering the channel, contractors also installed an engineered cattle drink and temporarily fenced of some sections of bank to exclude cattle. Volunteers then came in and installed brash bundles in a number of eroding sections, and temporarily fenced off some smaller areas. Bare banks were re-seeded and some bank side trees were planted. A length of brash bundling was installed along the old bank line where a large pool had eroded, where the channel had become over wide and where crayfish had eroded the bank. In addition a felled tree was staked in place to provide an in channel flow deflector and some rubble was moved to be added to an existing flow deflector. Monitoring continues but erosion has been reduced or eliminated in many places worked on and there is now a build-up of material re-creating the old bank lines behind the brash bundles. Clear gravel bars have formed where flow deflection has occurred and crayfish have been displaced where bundles were installed in front of their holes. Wardens continue to monitor these sections have reported that several new areas are now suffering from increased erosion. We are discussing a longer term solution with the land managers.
–Richard Lawrence (Bedfordshire Rural Communities Charity)
Projects/River Warden Updates – Flit
It has been another busy year keeping on top of the invasive Himalayan Balsam on the River Flit. Work has continued tackling the Balsam from its most upstream point, reducing the impact of seed spread downstream.
The Himalayan Balsam removal project covers 12.7km of the river Flit and tributaries plus 40.6ha of adjacent habitat comprising Flitwick Moor Sites of Special Scientific Interest (SSSI), three County Wildlife Sites (CWS), three non-designated areas of woodland, field edges and ditches. The Balsam project is entering a new phase where upstream areas of Balsam will be eradicated as far as practically possible to ensure the continued trend of reducing Balsam plant density downstream on Flitwick Moor.
The River Flit also has 4 river wardens currently surveying, covering the areas in and immediately around Flitwick Moor. These wardens keep a sharp eye on the Balsam in this area to ensure it is kept on top of, alongside their normal river warden surveying. With Flitwick Moor being a sensitive site it is also important the river wardens keep an eye on the areas of the Moor alongside the Flit that flood so we can continue to monitor the impacts of the enriched (and slightly alkaline) water from the River Flit on the more acidic Moor.
We want to know if you have seen this plant in your area. If you have seen this beautiful yet aggressive invader let us know!
Be sure to provide a location of any Himalayan Balsam you find so we can map it accurately.
– Lewis Dickinson (Wildlife Trust Beds, Cambs & Northants)