The Demonstration Test Catchments (DTC) project is a joint Defra, Environment Agency (EA) and Welsh Assembly Government initiative working in three river catchments – the Wensum in Norfolk plus the Eden (Cumbria) and Avon (Hampshire).

The overall objective of the project is 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. [READ MORE]


What's in the news?

  • October 2016: Sedimentary my dear Watson! Gatehouse sediment trap at Salle Three new roadside sediment ponds are being constructed on the Salle Estate to capture soil from damaged road verges, field entrances and areas of concrete hardstanding that is washed down roads during heavy rainfall events and into roadside ditches leading to the river. The ponds are designed to slow the flow of the run-off, allowing sediment to settle in the pond allowing cleaner water to enter the water course. The sediment traps are being funded by the Broadland Catchment Partnerships ‘SlowtheFlow’ project and are due for completion by mid-October. To monitor the effectiveness of the sediment ponds, new high-resolution turbidity probes have been installed upstream and downstream of the site to monitor how the ponds perform during rainfall events.
  • October 2016: How will Oilseed Rape compare as a cover crop? Following trials with oilseed radish as a cover crop and different cultivation techniques, all the fields at the Salle Estate that are part of the Wensum DTC study have been sown with oilseed rape. Field drains will be monitored this winter to see how effective oilseed rape is as a winter cover crop compared with oilseed radish at reducing nitrate leaching.
  • October 2016: Benefiting from a Biobed Biobed at Salle A proportion of the pesticides reaching our streams and rivers comes from the preparation and washing of the pesticide spraying equipment. A biobed provides a practical way to deal with pesticide residues that that occur in sprayer handling areas. As part of the work of the Wensum DTC in partnership with the Environment Agency and the Salle Estate, a compost-straw-topsoil biobed was installed which has been shown to reduce total pesticide concentrations in waste machinery washings by over 90%, thus minimising both surface water and groundwater pollution risk. The results of this research has recently been published in the Journal of Environmental Management.

  • October 2016: Welcome Maria! River sampling at BrisbaneOur newest recruit to the Wensum DTC team is Dr. Maria Hernandez-Soriano. An experienced environmental scientist, Maria has recently completed a 3 year post-doctoral fellowship at The University of Queensland (Australia) where she ran projects working on iconic aquatic ecosystems such as the Great Barrier Reef Lagoon.
  • October 2016: How to significantly reduce nitrate leaching losses Oilseed Radish Field trials on the Salle Estate covering 143 ha split into three blocks with differing cultivation techniques and a winter oilseed radish (Raphanus sativus) cover crop, revealed oilseed radish reduced nitrate leaching losses in soil water by 75–97% relative to a fallow block, but had no impact upon phosphorus losses. Average soil nitrate concentrations were reduced by 77% at 60–90 cm depth beneath the cover crop, highlighting the ability of deep rooting oilseed radish to scavenge nutrients from deep within the soil profile. However, employed alone, direct drilling and shallow non-inversion tillage (to <10 cm depth) were ineffective at reducing soil water nitrate and phosphorus concentrations relative to conventional ploughing. Applying starter fertiliser to the cover crop increased radish biomass and nitrogen uptake, but resulted in net accumulation of nitrogen within the soil. In terms of costs, there was negligible difference between the gross margins of non-inversion tillage (£731–758 ha-1) and conventional (£745 ha-1) operations, demonstrating farm productivity can be maintained whilst mitigating diffuse pollution. This work was recently published in the journal Aspects of Applied Biology.
  • October 2016: Congratulations Zanist! Who has successfully completed his PhD at UEA. His thesis is titled “Assessment of the application of a cover crop and conservation tillage on soil and water properties and on dissolved nitrous oxide in an arable system” and is based on work undertaken in the Wensum DTC.
  • 28 Jul 2016: Catching up with catchment news Two new newsletters have been added to this website - the latest roundup from the DTC programme, and also from the Broadland Catchment Partnership.
  • 27 Jul 2016: Excellent cartoon video from the Eden DTC Image from Sim Reaney's cartoon video This cleverly constructed cartoon video discusses in a very engaging way the costs of diffuse pollution to farmers based on the monitoring data from the EdenDTC project and illustrates the potential mitigation actions that could be taken to minimise the losses. To view it [Click here].

  • 07 Jul 2016: Sharing experience of integrated catchment management Ger Shortle at DTC meeting UEA July 2016 Catchment management practitioners got together with DTC researchers from the Avon, Eden and Wensum for a day-long meeting at UEA. Ger Shortle told us about the Irish Agricultural Catchments Programme that has been running for nine years. This project evaluates the effectiveness of the Government's Nitrate Actions Programme (NAP) which has stocking rates, N and P limits, slurry storage, spreading constraints, buffer zones etc, that all farmers have to abide by. Ger reported that reduction in stream P concentration took over 6 years to begin to be revealed and indicated that the project was highlighting that education and effective nutrient management advice and information (including encouraging active use of nutrient management plans as a management tool), as well as ensuring that the measures within NAP are being followed, were key to improving water quality. Neil Punchard of the Broadland Catchment Partnership impressed the audience with the volume and breadth of work that has been undertaken to develop the partnership and enhance the catchment in the four years it has been operating. Updates were also given on the DTC research. Afternoon workshops considered how the lessons learned from the DTC work could best be disseminated and the further work needed to overcome barriers to ensure better catchment management in future. For the key points highlighted from the workshops [click here].

  • 05 Jul 2016: Beans up to our ears! Bean field soil sampling at Salle Intrepid UEA researchers, deep in a jungle of beans. Searching for soil sampling sites when the growth is this high is no mean feat! The work must go on, testing bulk density, penetration and infiltration rate. With all those woollies who would believe it's July!

To read more about what's been happening see our News page.

View Wensum DTC Google Earth project
Wensum Google Earth project
Explore the Wensum catchment from the comfort of your own computer using this 'Google Earth' project developed by GIS expert Gilla Sunnenberg. [Click here] to view the project.
Out and about
Mill on the Wensum
Three arched bridge
Demonstration Test Catchments Logo