Within the South Chilterns Catchment the Middle Thames is the section that runs from the confluence of the River Thame with the Thames just north of Wallingford, south to Reading then north and east finally to Cookham near Maidenhead. The Thames skirts around the western edge of the Chilterns that is designated an Area of Outstanding Natural Beauty (AONB). The Middle Thames has been divided in to two parts Wallingford to Reading and Reading to Cookham.
This southern section of the Middle Thames starts at Reading where the Thames, after leaving the town, turns north, first towards Henley, then east to Marlow and on to Cookham, a total distance of 38.3 km (23.8 miles). This reach of the Thames features a number of locks of unique character and landscape importance including Hambleden Lock, Hurley Lock and Marsh Lock. The major tributaries that enter the Thames in this section are the Loddon at Twyford and the Wye at Bourne End. Also a number of smaller tributaries enter the Thames in this section: the Berry Brook at Shiplake, the Harpsden Court Drain west of Henley and the Hamble Brook at Mill End. Finally, there are a number of other small "winterbourne" streams that only flow during periods of heavy rainfall and high groundwater levels.
The Thames valley here is mostly medium grade agricultural land, a mixture of arable and livestock farming. There are areas of chalk grassland and beech woodland which are characteristic of the Chiltern Hills. The catchment also contain some extensive urban areas such as Reading, Henley, and Marlow.
There are a number of Sites of Special Scientific Interest (SSSI’s) and nature reserves in the area managed by the Chiltern Society and the Berks, Bucks & Oxon Wildlife Trust (BBOWT) such as Temple Island meadow, a species rich wetland with several floral species of local and national importance including the Loddon Lily.
The Thames is an important river for recreation in the form of coarse fish angling, boating (both commercial and leisure), canoeing, rowing, sailing, and rambling. There is a rowing club in most towns along this reach of the Thames. The most famous of all rowing venues, Henley, home of the Henley Royal Regatta and the River and Rowing Museum are located within this catchment. This catchment is also home to a number of canoe clubs and Hambleden Lock is popular for white-water canoeing.
The Environment Agency have Hydromorphologically designated the whole of the Lower Middle Thames as a heavily modified river as it is managed for navigation via a series of locks breaking up the natural flow of the river and effectively making it a series of managed impounded reaches. The total catchment area of the Lower Middle Thames is 238.6 km2 (92.1 miles2).
Environment Agency Classification for the Lower Middle Thames, Reading to Cookham
|2009 Cycle 1||2016 Cycle 2||Objectives|
|Water body status overall||Moderate||Moderate||Moderate by 2015*|
|Ecological Status||Moderate||Moderate||Moderate by 2015*|
|Chemical Status||Good||Good||Good by 2015*|
*As reported in Environment Agency's WFD Classification Status Cycle 2 v3 data set published 18th May 2017.
As can be seen from the table above, in 2016 the Environment Agency classified the water body status overall as Moderate. The Ecological Status was judged only as Moderate primarily due to the Physicochemical quality elements Phosphate and Biological Oxygen Demand.. This is suspected to be primarily due to a number of sewage discharges along this reach of the river. The Chemical Status was classified as Good. Overall water body status for this section of the Lower Middle Thames is predicted to remain at Moderate.
You can find out more about the classification of rivers in our catchment by using the Environment Agency’s Catchment Data Explorer