Closing the floodgates to Malta's storm chaos

In August 2007, Minister Ninu Zammit announced a project involving the excavation of a vast network of underground tunnels aimed at hitting two birds with one stone: solving the flooding problems in problematic areas while recovering a substantial amount of water which presently ends up wasted. But the project has now been scaled down after studies concluded that it was too expensive.  

The €55 million project, which is co-financed by the EU will see storm water diverted to an outfall in Ta’ Xbiex and Ta’ Barkat in Xghajra, is currently being assessed by MEPA. 

An Environment Impact Statement by Italian experts Politecnica has already been submitted and various public consultation meetings were held in the Summer. 

The aim of the project

According to the Environment Impact Assessment the aim of the  National Flood Relief Programme (NFRP) is to protect Malta from massive floods which normally occur every five years, and to ensure that in this event of flooding the water depth on Maltese roads always be under 10 cm level – above which, the flood will start producing damages.

Studies show that a flood management system would result in significant “savings” in damages and socio-economic and environmental losses.

But the study decries the complete lack of any detailed record on the damages occurred in the 2003 flood. It also reveals that no data is available concerning the damages suffered in the other floods experienced in the last decades. Not even the maximum water depth reached during the floods has been recorded.

Scaling down the project

Replying to a parliamentary question in May, Resources Minister George Pullicino confirmed that the project as scaled down, following the results of a feasibility study conducted by Isreali consultancy, Tahal.

“The studies have shown that the underground tunnel option to harvest rain water was not economically viable when compared to other solutions like the treatment of sewage for the use of agriculture and industry.”

The Israeli experts concluded that when the cost of the infrastructure required is taken in to account it would cost €80.31 to produce one cubic metre of water even more expensive than the €49 required to produce the same amount through desalinisation as stated in a parliamentary question in 2008 even if this amount did not take in consideration capital and depreciation costs.

According to Pullicino, the scaled down version of the project will still harvest 680,000 cubic metres of storm water, which can be made available for irrigation.

The decision to focus exclusively on flood relief was slammed by consultants who conducted a strategic environmental impact assessment (SEA) on the storm water master plan, arguing that storm water should be stored to alleviate pressure on the ground water aquifers.

The consultants claimed that “the revised Storm Water Master Plan (SWMP) does not put forward an adequate plan for an effective infrastructure which conserves the groundwater aquifers whilst solving the problems associated with flood relief.”

According to the study the original proposal to harvest water in tunnels would have resulted in the harvesting of between 5.5 and 8 million cubic metres of waters and  would have provided for 65% of agricultural needs.

Speaking to MaltaToday in February, Carmelo Mifsud Borg, who is responsible for the National Flood Relief project, explained that the main problem with reusing storm water is that as soon it drains into the road, it becomes contaminated.

“Once the water ends up in the road, nobody knows what it contains. It could get mixed with sewage, oils and other dangerous materials. To be reused, it has to be re-polished.”

And to capture and store storm water, a costly infrastructural investment is required.

“Economically, it does not make sense to let this water drain in the roads and then spend a lot of money to capture, store it and polish it to make it good for consumption and than to deliver it.”

According to Mifsud Borg, one way of solving the problem is to enforce the law requiring all houses to store rain water in a well rather than letting it off the road.

“Since the time of the Knights, households were required to store storm water in a cistern and this avoided the dispersal of water in the roads. Unfortunately, since the 1960s this law was not enforced,” Mifsud Borg said.

Energy performance rules for new buildings stipulate that all new development has to recover rain water.

“What is important is that this water is reused. If these cisterns become full the water will simply end up in the road.”

But the government has not abandoned all plans for harvesting storm water.

A 10,000 m3 capacity reservoir is planned at the end of Wied Ghollieqa (Kappara) to act as a temporary retention basin for storm water coming down from the same valley. and presently flooding the area of Triq Turu Rizzo, Triq Edgar Bernard, Triq Sliema down to The Strand.

It is estimated that 600,000 m3 of rainwater will be pumped from the reservoir annually, which will be made available for landscaping and agriculture.

A pipe connection will also be made with the Ta’ Xbiex sea outlet so that rainwater that is gathered at this outlet can be pumped to the reservoir when this is empty. It is estimated that from the Ta’ Xbiex spillway outlet it will be possible to pump around 600,000 m3 of rainwater annually.

The reservoir will occupy am  area of around 2080 sq.m. and its roof will be landscaped by providing a layer of soil and planting to make it blend into the existing landscape.

The Ta’ Xbiex outfall

According to government plans storm water will be separated from oils and grit along the roads before it enters the under ground tunnel network.

At present storm water is  discharged into the sea without any form of treatment The discharge point at Ta’Xbiex will also be equipped with a monitoring station to monitor the quality of the water before it is discharged into the sea. In this way, good quality water will be pumped back to a the reservoir near Wied Ghollieq in Gzira.

Ta’Xbiex  was chosen as the site of the outfall because water circulation in this area is much better than in other localities like Msida or Pieta.

Disposing storm water in open sea areas like Dingli or Pembroke was excluded because of the level of environmental protection enjoyed by these sites.

Government also claims that the option of disposing storm water to the open sea through an underwater pipeline or tunnel would have rendered  the whole project financially unfeasible.

Nor was this extra expense justified since storm water does not pose any significant environmental risk.