The Water Services Corporation is still counting the cost of the effects to its operations caused by the recent storms over the last weekend and last Monday.

The corporation extracts water from the underground aquifer, produces fresh water from the sea by means of reverse osmosis plants, which it distributes from reservoirs to its consumers and it is also is responsible for the collection and treatment of wastewater.

During the downpours sewage pumping stations failed to keep up with the massive increase in flow due to the huge amount of rainwater that entered the sewer system all over the Maltese Islands.

The corporation said it is estimated that every house connection that has an illegal storm-water connection to the public sewer system creates a 60-fold increase of its normal sewage flow.

In large wastewater catchment areas this resulted in scores of manholes being were lifted by the water pressure and carried for quite some distance. One manhole cover was not found. In such cases manholes cannot be replaced until the water flow subsides and repairs carried out. The pumping stations in these areas experienced an increase of 3.5 times the normal operation levels. However, no damage was noted.

Moreover, so much more foreign material also entered the sewers causing blockages further down the system that at the sewage treatment plants, even wooden planks had to be removed from the intake screens.

On the water production side, up until October 28, over 3,000 cubic metres per day of underground water were being lost because the boreholes and pumping stations are being “pumped-to-drain” until the turbidity (cloudiness) of the groundwater water comes back down to acceptable levels.

This turbidity is due to the excessive surface water that seeps through into the groundwater at an abnormally high rate without the natural filtration that would normally occur. Further major runoffs from farms or freshly fertilised fields caused shutdowns of groundwater sources due increases in nitrates.

At the seawater desalination plants, engineers adjusted the pre-treatment process prior to membrane filtration of the sea water because of increased turbidity at the sea shore wells, thereby avoiding the risk of plant shutdowns.

The buried infrastructure in all flooded areas withstood the storm and there were no signs of infiltration into the network which would otherwise had to be shutdown. The WSC worked around the clock with heavy machinery where necessary in order to rectify matters in the shortest possible time.

The corporation encounters similar problems every time it rains heavily due to the above mentioned storm water run-off from private roofs and yards that are illegally connected to the sewer system.