Chippenham Fen is a National Nature Reserve and SSSI in a predominately low lying arable setting. The site is supplied with water by a series of springs and is drained by the Chippenham River and a number of dykes and ditches. Monitoring at the site has been undertaken at a variety of locations and using a number of methods. A total of 15 dipwells have been installed across the site, 9 in 1976 and a further 6 in 1991. Three gaugeboards (GB1-GB3) have been installed at the Principal Spring (where a further piezometer has been installed), and within the site to monitor water levels in the dykes. These have been surveyed to Ordnance Datum and are monitored fortnightly. The dipwell data suggest that there is a distinct separation of trends over the recording period, with three distinct periods. There is a strong suggestion of a negative relationship between water supply abstraction and discharge in the Chippenham River, although the link may be related to the impact of fluctuations in rainfall on both data-sets rather than casual. The use of pumped storage to compensate for this abstraction has had relatively little impact on fen water table depths and Chippenham River discharge, although the exact magnitude of any effects may be masked by variations in rainfall and evapotranspiration. It is important that the amount of compensation water pumped into the Principal Spring is reassessed.
A printed copy of this old English Nature report is available from our Enquiry Service. Tel: 0845 600 3078 Email: enquiries@naturalengland.org.uk