The Misbourne is one of the Chiltern chalk streams, a globally rare wildlife habitat. Water emerges from the chalk as springs to feed the stream. In summer little rain percolates into the chalk and the head of the river moves down its valley. But in winter, if rainfall is heavy, the river starts flowing higher up.
Prior to a river rescue scheme in 1997, water companies were taking increasing amounts of groundwater so that in drought years the Misbourne virtually dried up. Since then pumping stations along the valley take less water and the river flow has recovered.
For more information about chalk streams:
Our photographs follow the course of the River Misbourne from a pond north of Great Missenden, through the Missendens, the Chalfonts, Amersham and Denham, to where it joins the River Colne near the start of the M40 motorway. It is a fickle stream in its upper reaches and in some locations we only have pictures of the dry riverbed.
Ordnance Survey grid references are quoted.