Sustainable Futures Farmer and Brand Partners met at Yorkshire Water’s Elvington Water Treatment Works on the 6th February 2018 near York, to understand more about the wider water supply chain and the influence agriculture can have on both quality and water processing demands.
Andy Shaw, who is the Product & Process Manager, Water Production – East, explained to the group how Yorkshire Water worked, and where the water came from to supply the Region. He outlined that Yorkshire was self-sufficient in water and that a grid system of pipes and pumps enabled them to quickly move water around the Region, making up for any shortfall in specific areas, and give the company flexibility and choices.
Yorkshire Water has 138 raw water reservoirs, which supply 45% of the water they need. A further 22% comes from underground aquifers via boreholes and the remaining 33% is extracted from rivers. In volume terms, the most important of these rivers is the Derwent. The water treatment works at Elvington accounts for nearly 20%, or one glass in every five, consumed by their customers across the region.
Water is pumped out of the river Derwent into one of three huge onsite storage reservoirs where some of the larger sediment can settle out. It is then pumped across into the water treatment plant. Here the water is mixed with very fine sand and Aluminium Sulphate, causing many of the particles of soil and organic matter to clump together and sink to the bottom as sludge. The clarified water with smaller particles and then filtered through a sand and gravel bed to remove further particulates, leaving the water progressively clearer.
They then bubble Ozone through the water to breakdown any herbicides or pesticides within the water. Unfortunately, this process is not able to breakdown metaldehyde residues from slug pellets, which is becoming an increasingly serious problem for Yorkshire Water. Finally, the water is then disinfected with Sodium Hypochlorite to kill any bacteria or any other pathogens.
Partners of Sustainable Futures visit a crop trial site
Water Supply and Farming
The Derwent is fed from a catchment of over 2000 square kilometres of both upland and lowland catchment, much of which is arable farmland. This is also true for the other river catchments such as the Ouse, the Ure, and the Wyske. As a consequence, farming practices in these geographic areas can have a significant influence on the actual quality of the water in the rivers.
Recent changes in weather patterns have greatly increased the occurrence of flash flood events when compared to rainfall statistics from previous years. These incidents increase the amount of soil erosion from surrounding farmland and as a consequence the levels of sediment in the rivers. Currently, Yorkshire Water disposes of over 11,000 tons a year of sediment collected from its Elvington Plant.
Yorkshire Water is keen to work collaboratively with farmers in these catchments to find ways of reducing soil erosion, and keeping the soil where it belongs, in farmers’ fields. A new Project called Sustainable Landscapes sponsored by Yorkshire water will work with farmers to explore new ways of approaching these problems.
One way to reduce erosion is to improve organic matter levels, which will, in turn, increase the water holding capacity of the land. Using cover crops can also have a beneficial effect on soil quality, when post-harvest cultivation can reduce the number of time fields are left bare, again preventing exposed soil from being subject to extreme weather events.
The Project will also look at how best to utilise nitrogen and phosphate in the farmed environment. If farmers can find ways to improve the overall effectiveness of fertiliser through, variable rate application, precision farming methods or the use of cover crops to hold beneficial nutrients within the soil throughout the winter, the longer term financial effect on farm profitability will be positive
The other key area of activity will be to find ways to reduce the levels of Metaldehyde in the water for which there is currently no cost-effective way of removing the pesticide from the water supply. The collaborative project will work with farmers to try alternative methods and techniques of slug management. This might include using mechanical controls, such as stubble raking and rolling, or alternative types of slug pellets which do not contain metaldehyde.
The use of precision farming techniques can also help to reduce the total amount of pellets used. This can be done by evaluating which areas of the field are prone to slug damage, recording this data electronically and then targeting these areas for treatment specifically, rather than undertaking a more general application across the whole field.
All those who attended the event agreed it was a fascinating visit and collectively gained a much better understanding of the water supply chain and the factors that influence it.
A big thank you to Andy Shaw for hosting the event and to Andrew Walker, Catchment Strategy Manager who will be undertaking an operational lead on behalf of Yorkshire Water for the Sustainable Landscapes programme.