The Misbourne is unusual in that along with its winterbourne headwaters, it also has an intermittently flowing middle section.  A change in the underlying geology south of Amersham causes the river to become ‘perched’ above the water table and as a consequence, the river loses water through its porous river bed.  Flow along this section is particularly vulnerable to drought, abstraction and to disturbance of the river bed. 

In the 1980’s the Misbourne was listed in the top 25 UK rivers most affected by abstraction.  In 1997 a low flow alleviation scheme was carried out reducing abstraction from pumping stations in the Amersham area by nearly 50%.  This scheme has helped to increase flows above Amersham but further measures are required to improve flows in the middle river.

Although altered by many centuries of human activity such as milling, watercress growing, ornamental landscaping and abstraction for public water supply, the Misbourne provides valuable habitat for a range of wildlife including, trout, mayfly, water rail, reed bunting, spotted flycatcher and sandpiper.

The route of Government’s proposed new High Speed 2 rail link through the valley will, if approved, have a major impact on water resources in the area and on flows in the river.

Never much more than a small stream, the Alderbourne flows predominantly through a rural landscape which includes areas of rare, wet woodland at Kingcup Farm.

Explore your local river

There are many attractive walks along our rivers and other waterbodies in the Colne Catchment. The Misbourne Valley walk, Chess valley walk and the Gade Valley discovery walk can be found here.