Boreholes, that are mostly to blame for the over-extraction of Malta’s groundwater, may offer the solution to replenishing the precious resource – by pumping rainwater into them.
Hydrologist and environmental entrepreneur Marco Cremona is suggesting channelling rainwater that falls on roofs into shallow boreholes from where water would dissipate into the ground.
“Run-off generated from rainfall on roofs is generally clean, and may only contain some silt or particles from traffic and maybe some bacteria from bird droppings,” Mr Cremona told The Sunday Times.
“Practically all buildings in Malta are guttered and the rainwater is collected and channelled somewhere. In cases where there is no cistern it is channelled into the sewage system or the street.”
His aim is to throw his idea into the public domain so that the authorities would pick it up and drive it forward.
Experts have warned that Malta’s groundwater resources are running out and may vanish within the next five to 15 years. According to the European Commission, the free use of groundwater must stop before the end of the year or Malta may face legal action.
Meanwhile, the government has started a borehole registration process in an attempt to curb abuse.
Mr Cremona, who had devised an award-winning project to treat and recycle wastewater from a hotel, is determined to see his latest proposal discussed.
“Implementing this solution for 15 per cent of Malta’s built up area will avert 20 million cubic metres of flood water and enhance groundwater recharge by a substantial 50 per cent,” he said, adding it would also help keep water prices affordable.
He underlined the need to further develop the idea, particularly with regard to determining the optimum depth of the borehole for different geological situations.
Explaining the rationale behind his suggestion, Mr Cremona pointed out that during last Monday’s storm, Malta was showered with about 27 million litres of rainwater. Last year, the Water Services Corporation extracted 12.7 million litres of groundwater for distribution as tap water.
Although it is impossible to collect every drop, Mr Cremona is convinced some of it may be saved.
About 30 per cent of Malta’s surface area is built and most is made up of roofs equipped with rainwater collection systems that channel water into cisterns, the sewage system, or into the street.
Given the fact that a law stating all houses should be equipped with cisterns or wells has been ignored for years, most of the water goes to waste.
To make matters worse, when large amounts of water gush into the sewage system it results in sewage outpours that contaminate the water in the streets.
Therefore, the ideal place to collect water is “upstream” rather than gathering it after it travels through roads and becomes contaminated, he said.
Since retro-fitting cisterns in buildings are practically impossible, this is where his idea fits in – to channel rainwater into the ground through boreholes.
The drilling of boreholes, to be financed by tenants, should be carried out by the WSC or licensed contractors who will ensure the borehole is sealed off and tamper-proof. Mr Cremona said sceptics may try to kill off the idea by saying it poses a threat to the quality for the groundwater.
“I counter this argument by saying: what’s preventing contaminated run-off (water) from infiltrating valleys lined with toxic rubbish from reaching the aquifers all around Malta?... What about the huge leakages from our sewage system?”