Borehole Bacteria Hampers Growers’ Irrigation Efforts
Potatoes are one of the most water-hungry crops and many potato farmers rely on boreholes for irrigation. Without proper maintenance however, boreholes can become contaminated with residue and biofilm, often caused by a build-up of iron-related bacteria (IRB). Pipes and borehole casings can become blocked, reducing the quantity and quality of water pressure, as one East Anglian farmer found out to his cost.
The two boreholes on his farm were struggling to deliver as much water as he needed, and he explains: “The borehole had only been installed the previous year and it quickly went from working very well to very poorly within a season. We know our strata suffers from iron ochre but we had expected to get five-six years from it before we had problems. Unfortunately, the iron bacteria impacted on performance much more quickly and we needed to get something done as a matter of urgency.”
The boreholes normally pump water into a ditch, from where pressure pumps feed the irrigators. In just 12 months, the yield from the largest of the boreholes went from 1.8 cubic meters a minute to less than half, at just 0.6 cubic meters a minute.
Having first had the borehole pump removed, the farmer called in borehole cleaning and rehabilitation specialists Treewaters Control Systems, which undertook an initial brushing and cleaning program, followed by a treatment of BoreSaver Ultra C Pro, specially-designed to eliminate iron bacteria in boreholes.
Treewaters’ Bryn Agers, explains: “The borehole was struggling with severe contamination. Typically, one dose of BoreSaver is enough to solve any problem, we leave the solution to work for a few days, continuing to test the pH level of the water during that period, and return to check on progress. On this occasion, we could see further work was needed, so we supplied a second treatment and undertook a further brush and clean of the borehole, then did another camera survey to make absolutely sure all the equipment and casings were clear.”
BoreSaver treatment, from Geoquip Water Solutions, includes a biodegradable marker, guaranteeing that no chemical residue is left in the water supply, therefore avoiding any detrimental impact on crops. A further benefit is that it can be used in situ, without the need to remove borehole pipes or pumps.
The farmer concluded: “The magic figure for borehole water to be able to run an irrigator properly is 0.9 cubic meters a minute – anything below that and we have to take water from our storage tanks to supplement borehole supply. Even though we have a reserve reservoir, in 2019 our other farm ran out of water and that impacted on our ability to fully irrigate our main crop of potatoes and onions, so we lost around 35% of our yield.
“Being able to self-dose this borehole with the treatment on a weekly basis we were able to increase our water yield back up to 0.92 cubic meters.”