Our UK client and his family are third generation farmers of watercress. They source their water from boreholes and the adjacent chalk stream, one of only 200 worldwide (source WWF.org.uk).

Unfortunately, due to the quality of the river water they have had their license to grow watercress withdrawn. In addition, because the borehole water is no longer artesian, possibly due to continued water authority abstraction from the aquifer, they found the cost of pumping water from depth prohibitively expensive. The outcome was that they had to diversify and look for alternative sources of power for their water pumps.

Although they received no compensation when their business was forced to close this family is remarkably resilient and entrepreneurial.

They applied for a grant to abstract water from the borehole using a solar powered water pumping system and diversified into fish farming. This is where they contacted SCL Water. For the last couple of years our Managing Director, Debby Appleby, has been in discussion with them offering advice and guidance and recently they were successful with their funding application.

Debby specified a Grundfos SQ Flex low head, high flow solar powered pump connected to ten 340 watt solar panels configured as two runs of five panels in series, which are connected in parallel.

These Grundfos pumps can run directly from a solar supply generating Direct Current (DC) or from single phase electricity generating 240 volts of Alternating Current (AC). As part of the specification therefore Debby included a Grundfos IO101 control box that allows the pump to be switched between power sources.

At full power the variable speed Grundfos SQF 14-3 solar pump can deliver up to 22000 litres of water per hour and as such can provide the cress beds, now stocked with rainbow trout, with a sufficient supply of good quality clean water directly from the aquifer.

Footnote: Whilst in conversation with our client he expressed concern about the efficiency of his old fixed speed pump supplying the farm house and cottage with treated water. We discussed the Grundfos single phase constant pressure system (CPS) as an alternative. As with the solar pump the CPS is variable speed and much more energy efficient than older conventional fixed speed pumps. Our client purchased a CPS with an SQE 5-70 pump from SCL. It is now installed and set to provide the buildings with water up to 7000 litres per hour at a constant pressure of 3 bar.

In summary, our UK client who had a thriving watercress business has had to diversify due to water quality and local abstraction issues. In so doing they have embarked on a journey to a zero carbon footprint where using solar energy and modern variable speed water pumping systems will go a long way to helping them achieve their goal.