Several clear flowing chalk streams have their source in and run through the valleys of the Chiltern Hills.
Chilterns chalk streams are fed from aquifers deep underground. The water rises up from clay beds through the purifying chalk layers emerging as very pure, crystal clear filtered water. The chalk bed of the stream helps to maintain the characteristic purity of the water.
For this reason Chilterns water has been extracted by water companies as an ideal source of drinking water. Unfortunately over the years this has led to a fall in water levels and some chalk streams even drying up altogether, a situation which the various water authorities are now working hard to address.
Chilterns chalk streams are very important habitats for a range of wildlife. The Chess is a fine example of a wonderful clear flowing Chilterns chalk stream and one that can be enjoyed by walkers of all abilities on the Chess Valley Walk.
Expect to see shoals of three spined Sticklebacks gathering in shoals in early summer and trout in the larger pools. Populations of great crested newts still thrive here. With luck you may spot a kingfisher on an overhanging branch or a yellow wagtail searching for insects at the waters edge.
The nearby River Misbourne has its source at Mobwell just outside Great Missenden, across the road from The Black Horse. Incidentally the Black Horse in Missenden is a great pub for food; walkers can start or finish many an adventure here.
The River Misbourne meanders through pastureland, is then ignominiously routed underground as it passes through the village of Great Missenden, emerges triumphantly at Warren Water beside Missenden Abbey and then flows on towards the Shardeloes Estate outside Old Amersham. In spring great crested newts can be found and in summer you may see a grass snake if you’re lucky.
Other Chilterns streams saw their importance diminish with the coming of the Grand Union Canal. The River Bulbourne at Berkhamstead runs alongside the canal and Wendover’s natural source, or Wellhead, became a channel, the Wendover Arm, to supply the Grand Union Canal. Nevertheless you can still follow the source at Wendover just near St Marys Church where there still remains a charming babbling brook.