The overall objective of the project has been described as ‘to provide evidence to test the hypothesis that it is possible to cost effectively reduce the impact of agricultural diffuse water pollution on ecological function while maintaining food security through the implementation of multiple on-farm measures across whole river catchments using local expertise to solve local problems.’ Long winded?
The theme of the conference was Progress and next steps in the Wensum Catchment. Everyone who attended was encouraged by the amount of progress that has been made. Unfortunately there was – as at last year’s inaugural conference – only one farmer present and not one single owner of land in the Wensum valley, so the conference was a bit of a student/academic/scientist’s mutual admiration session.
Two high-spec monitoring kiosks are on-site in the headwaters of the river Blackwater, a tributary of the Wensum, which sample and transmit data every half hour to the UEA. These state-of-the-art measuring devices will be used for long-term monitoring to both identify and record pollutants and to evaluate the effectiveness of measures to reduce them. Students make site visits twice a week to check and service equipment as necessary. One problem is that as water levels drop and silt builds up, the water flow meters function less efficiently, or if there is enough silt, stop working altogether.
It was interesting to see a map showing all the field drains on a significant area of land – there were hundreds! It is little wonder that silt getting into the Wensum is one of the major problems to be dealt with. While buffer strips alongside ditches, field drains and streams help reduce silt inputs, these strips need managing. The project hopes to develop methods of slowing surface water flows to allow sediments to drop-out and settle in areas where they can be prevented from entering the water course. Part of the study will aim to improve understanding of how to predict and control diffuse pollution from agriculture.
We were also shown how data can be analysed to show farmers how much of their expensive fertilisers they spread on fields draining into the Blackwater is literally going down the drain. Reducing this wastage has obvious cost implications for farmers as well as helping to improve the local habitat.
To find out more go to http://www.wensumalliance.org.uk/index.html
This project developed into a study of LWD restoration, a technique that has received mixed publicity but which presents a method for increasing biodiversity, increasing habitat for both inverts and fish whilst reinstating natural processes that are sustainable. It has been shown that well-placed and secured LWD can avoid problems of flooding, benefit fishing and present a quick, inexpensive and ‘natural’ method for the restoration of the hydrology and ecology of modified river channels.