The Enborne is a fast-flowing river, quite different in character to the rest of the catchment.
It rises south-east of Inkpen and flows east toward the A34, continuing on to join the River Kennet at Aldermaston. Ecchinswell Brook, Earlstone Stream, Burghclere Brook,Kingsclere Brook and Baughurst Brook all flow into the River Enbourne along its course.
Despite improvements in the quality of fish populations and dissolved oxygen and phosphate levels since 2016, the current (2019) status of the River Enborne is only moderate due to invasive North American Signal Crayfish, drought, land drainage and barriers created by ecological discontinuity. The river failed its chemical assessment in 2019 due to the presence of Polybrominated diphenyl ethers (PBDE).
- Slade Hill to confluence with the Kennet: In October 2022 a walkover was completed by ARK and confirmed the main barriers to fish passage on the Enborne are the EA Gauging weir, weir at Hyde End and the weir below Thornford Road ford. The walkover confirmed the, previously identified barriers, series of three weirs downstream of the A34 are all passable to fish and there is no longer a weir above the B4640 near the Swan pub.
- Hyde End to Bottle Cottage: near Shalford Farm, baffles were installed in 2008/9 to enable fish passage.
- Source to Penwood Stream: some change of management of the river is required to restore more natural conditions.
- Hatt Common: re-meandering would allow this reach to more closely match conditions found upstream and downstream.
- A34: a walkover is required to confirm if there are any signs of impoundments just upstream of the A34. Large woody debris could act as in-channel enhancements on this stretch. The series of small weirs just downstream of the road may be acting as a barrier to migrating trout under normal flow conditions and these should be removed or notched to provide free migration under all flow conditions.
- Penwood Stream to the weir at the B4640: a walkover is required to establish what degree of enhancement is appropriate. Confirmation is needed regarding whether the weir at the end of the reach obstructs fish passage.
- Weir at the B4640 to the ford at Thornford Road: a walkover is required to assess whether tree works are required and if there are any other enhancement works that would be beneficial.
- Ford at Thornford Road to Hyde End: two small weirs (one mostly redundant) exist roughly 400 m downstream of the ford and these form an impoundment which provides a feed to a disused water mill/summer house; removing these structures should be looked into as this would stop the impounding effect and enable fish passage under all conditions.
- Hyde End to Bottle Cottage: on the stretch from Hyde End Farm to Able Bridge the river lacks in-stream habitat features such as large woody debris or spawning riffles; small-scale habitat improvements would add diversity to in-channel features. In the woodland upstream of Bottle Cottage it may be possible to create a backwater but it will be necessary to identify whether the eastern channel is a naturally flowing bifurcation or if it’s silted up. A walkover is required to identify opportunities in this area.
- Bottle Cottage to confluence with the Kennet: a walkover is required to identify which channel here takes most of the flow and whether adjustments need to be made to this.