9.1. The Environment Agency has a duty to exercise a general supervision over all matters relating to Flood Risk Management. Certain watercourses within the Oxford area have been designated as Main River. The Environment Agency has permissive powers to undertake general maintenance and make improvements on Main River watercourses. As well as the River Thames and the River Cherwell rivers, the Botley Stream, Hinksey Stream, Bullstake Stream, Seacourt Stream, Osney Ditch, Castle Mill Stream, Peasmore Brook, Marston Stream, Hogacre Ditch (part), Bayswater Brook and Eastwyke Ditch in the Oxford area are all designated Main River watercourses.
9.2. Bayswater Brook is a natural earth channel 14km long. The 5km
long middle section forms the Barton and Sandhills Ward boundary with South Oxfordshire. It connects to the Cherwell north of the Northern by- pass road.
9.3. Botley Stream lies to the north of Botley Road. It is a 0.8km-long
natural earth channel cross connecting Seacourt Stream with Bullstake Stream.
9.4. Boundary Brook comprises 3km of earth channel, 0.3km of
culvert and 1km of concrete lined channel. There are two large silt traps along its length, which are the responsibility of Thames Water Utilities Ltd. One is located at Cowley Marsh Driftway and the second is adjacent to Iffley Road.
9.5. Bullstake Stream is a natural earth channel 2.5km long. It begins
north of Botley Road at a confluence with the River Thames and reconnects with the Thames at a confluence south of Botley Road.
9.6. Castle Mill Stream is a 5.5km long channel running through the
City centre. It begins at the Binsey Boat Yard and re-connects to the Thames south of Oxpens Road Bridge.
9.7. Eastwyke Ditch is an earth channel 3.2km long. It begins at a
confluence with Hinksey Stream and runs east to connect to the Thames east of Abingdon Road.
9.8. Hinksey Drain comprises 1.04km of earth channel in the Thames
floodplain. It begins north of Abingdon Road where it splits with the Hinksey Stream along the western boundary of the main Birmingham- London railway line. It rejoins the Hinksey Stream to the rear of the properties in Kennington Road, Kennington via a bridge culvert under the railway.
9.9. Hinksey Stream lies to the south of Botley Road and is a 4.2km
Stream it runs south and reconnects with the Thames at a confluence south of the southern bypass road.
9.10. Hogacre Ditch (west section) is an earth channel 1.9km long, south of Botley Road. It begins at a confluence with Bullstake Stream running south and connecting to Hinksey Stream.
9.11. Holywell Stream comprises 1km of open channel in the Cherwell floodplain. It begins at a confluence with the Cherwell in University Parks and rejoins the Cherwell at Magdalen Bridge.
9.12. Littlemore Brook comprises 1.6km of a natural earth channel within the City boundary, commencing south of Kestrel Crescent, and running into South Oxfordshire District, west of Oxford Science Park. 9.13. Marston Brook is a natural earth channel 2.9km long. It drains the Old Marston area and connects to the Cherwell east of Norham Gardens. 9.14. Northfield Brook comprises 2.2km of re-graded earth channel within the City boundary. It begins within South Oxfordshire’s District and joins Littlemore Brook north of the Kassam Stadium.
9.15. Osney Ditch is an earth channel 1.7km long. It begins at the confluence with Bullstake Stream near to Binsey Lane Bridge and connects to the Thames at the Osney Lock.
9.16. Peasmore Brook is a natural earth channel 2km long. It drains the New Marston area and connects to the Cherwell east of St Cross Road. 9.17. Redbridge Stream comprises 0.7km of earth channel in the Thames floodplain. It begins at a confluence with Hinksey Stream north of the old Abingdon Road and rejoins Hinksey Stream adjacent to Abingdon Road Bridge.
9.18. Seacourt Stream (or Wytham Stream) is a natural earth channel 12.7km long. It begins north of Wytham Village and connects to Bullstake Stream at a confluence near to North Hinksey Lane.
9.19. Wareham Stream comprises 0.5km of open channel in the City centre. It begins at a weir in Upper Fisher Row and rejoins Castle Mill Stream near to Oxford & Cherwell Valley College.
9.20. Weirs Mill Stream comprises an earth channel 2.1km long. It leaves the main Thames channel by Long Bridges and rejoins the Thames at a confluence south of the southern bypass.
9.21. Figure One is a map showing the location of the Main Rivers in and around Oxford and an indicative outline of the flood zones.
9.22. The common-law responsibilities of riparian landowners still remain on Main Rivers, under which the owner has a duty for maintaining
watercourses irrespective of its designation. The Environment Agency produces the booklet “Living on the Edge” which is a guide to the rights and responsibilities of a riverside owner and is available from the Environment Agency national customer contact centre on 08708 506 506 and website (environment-agency.gov.uk).
9.23. The Environment Agency operational teams carry out routine planned and reactive unplanned maintenance work on Main Rivers. The Environment Agency consults with riparian owners and other parties with a direct interest in the planned work. The work includes vegetation clearance and silt removal to provide an effective watercourse whilst maintaining the natural biodiversity.
9.24. There are three pound-locks on the Thames in the City Council’s area. They are the Godstow, Osney and Iffley Locks and are vested in and operated by the Environment Agency.
9.25. At times of high flow the Agency’s operational role switches from that of routine maintenance to damage limitation. Operational priorities are to check, operate and carry out running repairs to Environment Agency- owned water level control structures, pumping stations, flood storage and diversion works, flood-stressed defences and trash screens, and to clear debris and obstructions where possible and advise other riparian owners as to their maintenance responsibilities. The operational role also includes the monitoring of water levels, telemetry, weather and rainfall forecasts and keeping professional partners informed.
9.26. The Environment Agency manages Main River watercourses in the Oxford area from the West Area Office, Red Kite House, Howbery Park, Crowmarsh Gifford, Oxfordshire, OX10 8BD.