Southern Streams : The Kennet Catchment

The Southern Streams are all chalk stream tributaries of the River Kennet that flow in from the south. They include the Dun, the Shalbourne, Froxfield Stream and Inkpen Stream.

The streams receive and convey significant quantities of nutrients and sediment into the River Kennet and the Kennet and Avon Canal.

In 2012 ARK’s Kennet ‘Southern Streams Project’ focused on this area to identify and solve sources of pollution. Most of the pollution is from diffuse sources, and is being addressed through Catchment Sensitive Farming advice. A team of volunteer ‘muddy walkers’ has since collected evidence of sediment pathways reaching the rivers and in 2019 a Southern Streams farmer group was established with water quality as a principal focus.

The Southern Streams were the focus of the successful Green Recovery Challenge Fund project ‘Sparkling Streams’ which ran from 2021 until 2022. The project was a partnership between Action for the River Kennet, North Wessex Downs AONB, the Southern Streams Farmer Group and Hungerford Town and Manor. You can see a summary of what benefits were achieved here.

River Dun

The Dun is a famous trout fishing river, running through the Freeman’s Marsh Site of Special Scientific Interest (SSSI) near Hungerford and joining the Kennet at Denford. Its waterbody status (2019) is moderate due to sewage discharge and inland boating structures, although dissolved oxygen and plant populations have improved since 2016. In 2019 the stream failed its chemical assessment due to the presence of Polybrominated diphenyl ethers (PBDE).

Actions completed:

In Hungerford at Bearwater: A larinier fish pass was successfully installed on the River Dun in October 2022
Adjacent to Berkshire Trout Farm: below the trout farm and up to the confluence with the River Kennet, habitat enhancement including narrowing and fencing has been carried out. This work has been successful, with some excellent habitat forming.
Between Great Bedwyn and upstream of the Berkshire Trout Farm: at the North Standen Estate habitat restoration has been carried out. At Freeman’s Marsh a significant amount of work has been carried out by Hungerford Town and Manor to improve the Dun through this reach, including fencing to reduce livestock access and narrowing the channel to a more sustainable width. A small structure was also removed, and this has improved habitat and fish passage. In 2012–15 a project was undertaken to construct seven bypass weirs adjacent to the seven locks along the K&A Canal to improve water quality within the River Dun catchment by preventing the mixing of canal and river water; this has been a successful project with reported significant improvements in water quality, macrophyte growth and silt deposition. During 2018 ARK worked with the Bearwater Community to improve river corridor habitat by planting up river margins and reinstating a more natural and sinuous river corridor.

Actions required:

Adjacent to Berkshire Trout Farm: a walkover will be required to assess if there are any enhancement opportunities within the constraints of the current environment.
Between Great Bedwyn and upstream of the Berkshire Trout Farm: near Oakhill Farm options for a fish passage have been investigated but not implemented. Between Oakhill Farm and the Hungerford Dun Gauging Station the channel is wide and shallow and enhancement options require investigation. The gauging station is a barrier to fish migration and has an impounding effect upstream; a feasibility report is necessary to see how the impacts of this structure can be reduced whilst still maintaining an accurate gauging record at the site. Low-cost baffles may be an option to secure fish passage. In 2022 the barrier at Bearwater was made passable. Further barriers identified by the ObstacEels project in 2021 remain to be tackled.

River Shalbourne

The Shalbourne Stream is a tributary of the River Dun. It rises from springs in the Upper Greensand and flows North for 6 km across the upper chalk through agricultural land towards Hungerford. Until 2000 the Shalbourne flowed directly into the Kennet and Avon Canal. In 2000 it was diverted back to its natural course, and then underneath the canal through a culvert to join the River Dun. This has improved water quality in the lower Shalbourne and the River Dun, but the culvert presents an obstacle to fish migration. Since 2016 its waterbody status improved from poor to moderate due to improvements in the quality of plant (Macrophyte and Phytobenthos) populations. Poor nutrient management, ecological barriers and land drainage negatively impact fish populations, explaining why their status is only moderate. Sewage discharge has led to poor phosphate levels and has negative effects on plant populations. In 2019 the stream failed its chemical assessment due to the presence of Polybrominated diphenyl ethers (PBDE).

Actions completed:

Upstream of the confluence with the River Dun: fish easement project was completed on a weir in September 2022.
Stype Mill: a fish passage feasibility study was completed as part of the Sparkling Streams project and the project implemented in 2022. A section of river remains impounded by the Mill and there may be further opportunities to improve habitat.
Eastcourt Farm to Standen Manor: at the remnant channel at the Old Mill House the impact of large flocks of ducks disturbing silt and sending plumes of silt downstream has been largely resolved in 2020.
Standen Manor Action for the River Kennet worked with the landowner to reinstate the channel to the middle of the floodplain in 2024, taking it away from it’s artificial perched route.

Actions required:

Eastcourt Farm to Standen Manor: an investigation is required to see if, at the top of the reach (which is dominated by a series of on-line lakes which are historic watercress beds), there is a suitable way of bypassing these lakes to allow the channel to recover naturally. Where the river flows past Eastcourt Farm restoration requirements should be investigated as there are numerous structures on this reach which are not passable by fish. Just above Standen Manor there may be habitat improvement opportunities.
At the Old Mill House, fish passage improvements and habitat restoration should be investigated.
Confluence with the River Dun: In Hungerford the River Shalbourne Gauging Station is a barrier to fish migration and upstream of the structure the channel is impounded and silty; a feasibility report is needed to see how the impacts of this structure can be reduced, possibly installing low-cost baffles to secure fish passage if the structure cannot be removed. There may be further opportunities reinstate the channel downstream from the 2024 project at Standen Manor.

Froxfield Stream

The Froxfield Stream is a tributary of the River Dun. Its waterbody status (2019) is moderate due to the effects of sewage discharge on phosphate levels and Macrophyte and Phytobenthos populations . Dissolved oxygen levels have improved since 2016. In 2019 the stream failed its chemical assessment due to the presence of Polybrominated diphenyl ethers (PBDE). The stream flows mainly through agricultural land, parallel with the A4 west of Hungerford.

Actions completed:

River habitat restoration and the creation of a new wetland to manage highway runoff was carried out by ARK in 2019. Further work has removed instream barriers.

Actions required:

There is a siphon at the end of Froxfield Stream, which carries water under the canal and into the Dun. A walkover is required to check whether it is possible to secure fish passage.