Lower Kennet

The Lower Kennet is generally recognised as the section between Newbury and the confluence with the Thames at Reading.

Lower Kennet

Several tributaries join the river through this section, the more significant being the Lambourn, a chalk-fed river joining just east of Newbury, and the Enborne, and Foudry Brook, largely rain-fed streams joining at Aldermaston and Fobney. In general, the river below Newbury has been considerably affected by man’s influence over hundreds of years. The waterbody status (2019) for the stretch Kennet/Holy Brook is moderate due to low dissolved oxygen (sewage discharge and urban development), and barriers to fish passage (ecological discontinuity and land drainage). The status from the Lambourn confluence to the Enborne confluence is also moderate, due to poor nutrient management, inland boating and structures, and North American signal crayfish. Both sections failed their chemical assessment, due to the presence of Polybrominated diphenyl ethers (PBDE) and the Kennet/Holy Brook section also contains the priority hazardous substances Benzo(b)fluoranthene, Benzo(g-h-i)perylene and Perfluorooctane sulphonate (PFOS).

Significant historic modifications include:

  • A large number of mills along the river’s course with their associated impoundments and by-channels. These include those at Greenham, Ham Mill, Chamberhouse (Thatcham), Brimpton, Aldermaston, Padworth, Sulhamstead, Theale, Burghfield, Southcote and Fobney.
  • The construction of the Holybrook which flows from Theale to Reading via Calcot Mill and takes a proportion of the volume of flow between those points.
  • The construction of the Kennet and Avon Canal, which shares the river channel in many sections resulting in a more uniform profile than the more natural combination of shallows with deeper pools.

Recreational use of the river reflects these factors:  boaters, towpath walkers and cyclists have access along canalised reaches. Angling on the lower river is largely for coarse fish and most stretches are managed by local clubs and associations giving ready and inexpensive access.

Actions complete:

  • Ham Mill: fish passage has been secured.
  • Downstream of Ham Bridge to Chamberhouse Farm: fish passage has been secured along the reach, including at Dog Head Stakes, and a project has been delivered to put in woody debris and create backwaters.
  • Chamberhouse Mill and Brimpton Mill: fish passage secured.
  • Thatcham Reedbed Improvement project (BBOWT).
  • Old Mill at Aldermaston to Ufton Lane: at Old Mill, Aldermaston a technical fish pass has been installed into the Enborne at this point; at Padworth Weir a technical fish pass has been installed; at Padworth Mill woody debris has been introduced and two backwaters have been created.
  • River Kennet from Tyle Mill to Garston Lock: a fish pass has been installed at Tyle Mill. At Sulhamstead Weir the angling club do regular maintenance work to try to retain the trees within the channel. At Lower Benyons two dedicated backwaters were created in 2015 and a livestock drink was also created which will act as a fry refuge but keep sediment runoff into the river to a minimum. At Osier Bed Stream a natural bypass channel was created to provide fish passage to the River Kennet. This needs to be monitored to ensure it is working as expected. A 500 m length of the Osier Bed Stream has been enhanced. At Shenfield Mill a larinier fish pass has been replaced with a natural bypass channel when an Archimedes screw was installed as part of a hydropower scheme; the benefits include providing juvenile habitat and potential spawning opportunities within the channel. Below Shenfield Mill one of the redundant oxbow lakes has been reconnected to the river, which has created an excellent area for fry refuge, as well as general biodiversity.
  • Garston Lock to Fobney: at Burghfield Mill fish passage has been secured. Near Southcote Weir the local angling club have reconnected an existing pond on the island to create a valuable fry refuge on this part of the river.
  • Fobney Island: a restoration project has been completed, turning former rough grassland into a wetland area and restoring the river to a more natural state.
  • West End Brook: enhancement work has been carried out at Simm’s Stud Farm, where step barriers were installed to slow the flow and divert it into a ditch to stop sediment input into the brook. At Simm’s plantation gravel was introduced above and below the culvert to increase the water level.

Actions required:

  • Downstream of Ham Bridge to Chamberhouse Farm: there are opportunities for habitat enhancements.
  • Chamberhouse Farm to Brimpton Mill: effort should be made to increase habitat diversity; enhancement options include installing large woody debris and creating backwaters.
  • Crookham Manor: provide fish passage on the sluices downstream of the manor. Initial designs have been created.
  • Priors Moor Ditch: the main objective is to provide fish passage on the sluices downstream of Crookham Manor. As part of this fish pass, habitat enhancements, possibly including the installation of large woody debris, could be carried out with little investment.
  • Wasing Estate: opportunities to work to secure enhancements, such as creating backwaters, should be pursued.
  • Old Mill at Aldermaston to Ufton Lane: at Padworth Mill continued small-scale enhancement works, such as projects to open up old oxbows and introducing woody debris to increase cover habitat for fish, would be beneficial. Widening the buffer zone and planting a range of tree species will also help to provide future habitat. Towards the end of the reach a feasibility study is required to see how reinstating a side channel, thought to be the original course of the river, could be achieved or whether it would be just as beneficial to enhance the existing channel.
  • Wasing Stream and Sulhampstead Mill Stream: this has the potential to be a very nice channel which offers fish recruitment/refuge from the main River Kennet. Looking at how to increase the connectivity and maintain flow would be beneficial. A walkover is required to assess enhancement options, including small-scale in-stream enhancements.
  • River Kennet from Tyle Mill to Garston Lock: Osier Bed Stream has sufficient woody debris but continued canopy removal would be beneficial. Adjacent to Arrowhead Road, the Kennet has a high rate of erosion and is over-wide; possible enhancement works include the introduction of large woody debris. Downstream from Shenfield Mill, ARK are in the process of improving the habitat of the oxbow lake and reconnecting it, and this will provide an additional refuge area for juvenile fish.
  • Garston Lock to Fobney: from Southcote Weir there is a possible enhancement opportunity to lower the banks, but the gravel pits may constrain this type of work. There are also possible opportunities to reconnect the river with the old channel in this section.
  • Fobney Weir: options for a multi-species fish pass should be examined. At the Old Turbine House there are discussions about installing an eel fish pass to open up access into the canal reach.
  • Fobney Island to County Weir: retaining tree cover would be beneficial.
  • County Weir to the confluence with the River Thames: a feasibility study should be undertaken to identify how County Weir could be made more passable for fish. Floating pennywort is present in this reach and the EA are monitoring the growth and controlling the spread of this invasive non-native species with the aim of complete eradication.
  • Clayhill Brook: a walkover is required to identify restoration options.
  • Bishops Wood Stream: a walkover is required to identify restoration options.
  • Silchester Brook: the fluvial audit’s recommendations include introducing riparian woodland in areas, putting deflectors and woody debris in the low-sensitivity reaches and looking at the scope for re-meandering just upstream of the confluence with the West End Brook. The ford at Clapper’s Farm is a barrier to fish in low flows; however, downstream of the farm the river is very sinuous and supports a very good quality habitat and this could be used as a reference reach. A walkover is required to assess enhancement opportunities and to check if we agree with the fluvial audit’s recommendations.
  • West End Brook: at Kiln Pond a possible restoration target would be to take the lake offline and bring the brook back through its original course, restoring approximately 1.5 km of channel. A walkover is required to assess the current state and identify if this is still a viable option. At Lovegrove’s Farm there is a weir with an 8-foot drop which is causing an impoundment and is a barrier to fish; fish passage options should be investigated. Fish passage at Kiln Ford should also be considered.
  • Continued farm advice to promote river friendly farming.
  • Yellow Fish, Muddy Walks and other campaigns and activities to reduce pollution.
  • Support for good Sustainable Drainage, Natural Flood Management, Rain Gardens and depave projects.