As part of a national drive to gather evidence that catchment management can have a significant impact on raw water quality DEFRA are currently funding a £5 million Demonstration Test Catchment (DTC) Project across three catchments: the Hampshire Avon, the Wensum and the Eden. The aim of DTC Projects is to evaluate the effectiveness of on-farm measures to improve water quality when their delivery is scaled-up to a real-life whole sub-catchment situation. .
The Westcountry Rivers Trust’s current Upstream Thinking Project on the Caudworthy Water, a short (~3.5 km) tributary of the River Ottery in the Tamar catchment, now represents a satellite study of the Hampshire Avon DTC. The DTC consortium is undertaking a detailed monitoring programme before and after the a comprehensive farm investment and advice programme being delivered across the catchment.
Two monitoring stations located at the middle and bottom of the catchment have been recording total nitrogen, nitrate, nitrite, soluble reactive phosphate, total phosphate, turbidity, suspended sediment concentration, dissolved oxygen, temperature, pH, ammonium, chlorophyll, effective particle size and discharge.
In addition to this chemical monitoring programme, extensive biological monitoring has also been undertaken in the catchment, including the assessment of macro-invertebrates, benthic algae (diatoms), macrophytes and fish.
The baseline data for Caudworthy Water has been collected over an 18 month period and Westcountry Rivers Trust have approached all twenty-four farmers in the Caudworthy Water sub-catchment. To date, over £450,000 has been invested in around £700,000 worth of capital investments with Best Management Practices ensured through the application of a Restrictive Deed on 19 of these farms.
Following the implementation of the Best Management Practices in 2012-13, the effects on water quality will then be monitored over 2013-15.