by Sheria Brathwaite
The Barbados Water Authority (BWA) has announced a series of measures to tackle the persistent issue of discoloured tap water stemming from the Bowmanston Pumping Station in St John.
These include assistance from the private sector to supplement water to customers fed from that station, minimal pretreatment to minimise the discolouration of the water, and installation of more water community tanks.
Officials have blamed recent “sharp, extended” rainfall for causing a significant problem at the station as several inches of runoff water has been clouding the water.
During a press conference at the BWA’s Pine, St Michael headquarters, they explained how the runoff stirred up water that was occasionally chalky and muddy, known as turbidity.
Director of Engineering Charles Leslie said: “The catchment that feeds Bowmanston extends as far up as Clifton Hall, Venture, all of those areas. So once rain falls in any of those areas upstream, what’s been happening is that some of the topsoil material has been washing into the cave system. Bowmanston is in a stream system that runs in an underground cave; the water becomes cloudy and then we have to stop periodically to avoid pumping that cloudy water into the system.
“This year has been extremely challenging . . . because we’ve been experiencing more frequent and sharp extended showers than we have been experiencing in the past. This has created a situation where we have to stop the station more often to allow the water to clear and once that water has been cleared we continue pumping.”
Technical advisor Dr John Mwansa said that this was the first time the authority had to shut down the station so many times, noting that climate change played a significant role in this development.
“People may ask what has changed,” he said. “Historically, we have had problems that led to shutting down Bowmanston but it was never this frequent. We might have shut down the pumping station maybe once or twice in a year. So far, we have shut down the station more than six times this year. So what is the cause? “The cause is essentially the fact that the rainfall pattern has changed. You are getting heavy rainfall over a short period of time and when you get heavy rainfall over a short period of time, you’re going to get run off and it’s that runoff that runs into the Bowmanston cave.”
Leslie explained that two systems operated from Bowmanston: a gravity-fed system that services St George residents in Greens, Ellerton Superlative and Salisbury and a pumping system that supplies water to residents in St John districts such as Clifton Hall and in St Philip as far as Blades Hill and College Savannah.
Mwansa added that in the past, people who lived upstream of the station planted khus-khus grass and hedge rows to keep the top soil from running off but that was no longer in place.
He said the BWA would create a special management programme to get residents to replant these hedgerows to mitigate against soil erosion, adding that it would “contribute significantly to minimising the impact and the frequency of shutting down”.
But the former BWA general manager warned that outages would continue and even increase in some instances, suggesting that additional measures would have to be put inplace.
Leslie outlined a series of short-term measures the BWA has been trying to alleviate outages. Ten additional community tanks have been installed in Drax Hall, Greens, Ellerton, Clifton Hall, Gall Hill, Cliff Cottage and
Webb Hill among other districts, he said, adding that more community tanks are scheduled to be installed in the coming weeks.
To date, 110 water tank systems have been installed in the affected areas in St John: 69 potable water tanks and 41 rainwater tanks for community centres, farms and households.
In St George, 113 water tank systems were installed: 86 potable water tanks and 27 rainwater tanks again to community centres, farms and households. A survey of the most vulnerable households was conducted and fifty additional households in St George and St John were identified this past week to receive personal tanks. The survey is to continue and installation of these systems is expected to take place within the coming weeks, the BWA said.
As part of the short-term measures, workmen will also fill the reservoir at Bowmanston using a supertanker with some assistance from the private sector to augment the potable water being supplied to customers fed from this station, the officials told reporters. The BWA is also on standby to supply communities as needed.
Mwansa said the water going to residents would be minimally pretreated to minimise the discolouration.
“It will help us reduce the turbidity up to a point and it is also worth pointing out that the BWA carries out continuous monitoring of our water quality and disinfection so that we chlorinate the water to provide disinfection. So it is protected from bacteria and viruses which makes it safe to use,” he said.
Private engineering firm Stantec Consulting Caribbean Ltd. has been assisting the authorities in implementing longer-term measures to reduce turbidity. Stantec’s Robert Reno said infrastructure upgrades were set to begin in February during the dry season and would include work at Pool Gully and the Bowmanston reservoir.
At Pool Gully, a series of check dams will be built to help slow down the flow of water to allow for fine clay sediment to settle before going into the cave system. A tank is to be erected at Bowmanston so the reservoir can betaken offline for cleaning.
The Bowmanston aquifer was cleaned back in 2016 and 2017. The vast cave extends between Pool and Kendall plantations, a twohour walk in and out.
Over the long term, the dams and additional reservoirs would be commissioned for permanent use, BWA officials said.
sheriabrathwaite@barbadostoday.bb
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