An exploration of the chalk springs and streams around Princes Risborough, below the northern scarp of the Chiltern Hills.
I think it was Einstein who said “The more I learn, the more I realise how much I don’t know.” and since becoming Chairman of the Chiltern Society Rivers & Wetlands Group, I have been amazed by the number of aspects of our English landscapes that I was completely unaware of; until I actually looked. This came home to me once more on Saturday when I took advantage of a little February sunshine to explore the chalk streams below the Chiltern scarp slope, around Princes Risborough. I have campaigned for local waterways, taken hundreds of landscape photographs and written books on the landscape but had no idea about the rather magical chalk springs that litter the rural plain from Ewelme in Oxfordshire to Luton in Bedfordshire, providing pure, clean water for homes, farms and wildlife.
The Chiltern chalk streams, such as the Chess and Misbourne, carved out their river valleys that are at the core of the pattern of settlements throughout the Chiltern area, as the many mills were placed along rivers and people earned a living from fish, watercress and agriculture. However there are no streams at all along the steep northern scarp slope of the hills, so where does the water falling on them go? The answer is that it disappears from the surface into the fractured chalk below, where it descends through cracks and natural ‘pipes’ until it joins the main body of water stored in the chalk: the aquifer. Below the scarp, at about 100 metres altitude, the chalk is initially close to the surface and in some places, water is pressed out of gaps in the rock to emerge onto the surface as a spring. There are a lot of them, but they are not well-known because they may form a pond, so are hidden, or are rather small and dispersed around an area which is usually sunken and may be overgrown with vegetation benefiting from the damp conditions.
The notable exception to this is the Lyde Gardens in Bledlow, owned by the Carington Estate, in which the springs, once exploited for watercress beds, have now been turned into a garden with public access. It is a surprising and rather magical place: very beautiful and also an excellent location in which to appreciate the chalk springs.
Just to the east is the spring-fed pond at Frogmore Farm whose stream supplies ponds at Horsenden, and once filled fish ponds. South-east of this is a hollow that contains at least two springs feeding a stream that flows through Saunderton (see below). The reason that areas containing springs like this are sunken is that the water is eroding the chalk underneath, forming sinkholes which eventually collapse, and the results can be clearly seen at this site which is covered in tussock grass rather than scrub. At Saunderton there are more springs, one of which could be seen surging up into a pond with some force, and others forming a small, scrubby marsh behind the church. A considerable flow is generated by these which feeds two large ornamental ponds and the brook that leaves the village.
The final stream in this little network runs through the southern edge of Princes Risborough whose water originates from Pyrtle Spring (see above), a spring at Culverton Manor and further springs at Monks Risborough on the northern side of the town. The resulting stream feeds Park Mill on the B4444 Summerleys Road which is now a busy site with numbers of tipper trucks coming and going. Efforts have been made to landscape and protect the stream around the property, but on the day I visited, dirty water was running off from the road into it.
The springs in this area are tributaries of Cuttle Brook which, in turn, joins the River Thame at the town of Thame. They meander across the flattish agricultural landscape and tend to suffer from a big problem for all of the chalk streams in that they are mostly small, with variable flows and often shallow depths, so they are just not seen as important. Whilst lots of pretty ponds have been created in settlements in this area to augment the visible water and benefit from the resulting scene, the streams are generally ignored so become overgrown and invisible. However almost all are clear and flow over clean gravel, although there was an exception at Horsenden Manor Farm where the pond surface was strewn with duckweed, indicating a high level of nutrients. This seemed to emanate from a duckweed-covered ditch a few yards away, and higher up.
This environment is very different from on the Chiltern dip slope and it never occurred to me that the brooks in this area were actually chalk streams. The number of attractive ponds and the heritage attached has also been a surprise and I shall certainly be taking a closer interest during future walks in the area.