Civilizations throughout history have thrived only where water was available. They declined when water became perennially scarce.
It is no secret that Malta is a water stressed country. Maintaining a population and an economy on this island state is, like any other state, dependent on an adequate supply of water. Malta’s supply has been entrusted to a non-renewable engineering solution dependant on desalination and unsustainable extraction of water from a depleting aquifer confirmed by deteriorating water quality.
Our demand for water shows a relentless upward trend quenched by greater dependence on desalination and underground water extraction. The aquifer shows an upward trend too but unfortunately only in its salinity and the concentrations of other undesirable infiltrations. This resource is fast becoming unusable to the extent that in some zones it increases soil salinity when used for irrigation. There is only one controversy. It is not about whether the aquifer will become unusable, it is about when.
With due respect to our politicians and their aids, they have redefined the meaning of the word sustainable. Malta’s major issues are de facto all unsustainable. Agriculture, water extraction, land use, waste disposal and population growth – to mention what comes to mind – are all unsustainable. Lifestyle ‘improvements’ on this island have become coupled to deteriorating resources no better exemplified by the dwindling supply of renewable potable water.
The only potential renewable water source is rainfall as long as it keeps falling in reasonably predictable quantities. It is also the only means by which Malta’s aquifer could recharge itself to allow sustainable extraction. In spite of inconveniences caused by instances of heavy rainfall, this has always been cherished till today. From tomorrow we plan to create a system to dispose of rainfall as fast as we can by building a network of run off tunnels leading to the sea. As the younger generation would thoughtlessly say: cool!
Let us be objective. When we have heavy rains, we do get traffic disruption, some damage to property and rarely a life is lost. However, do a few days a year of flooding justify spending €40 million if the only result is doing away with this inconvenience and then only in some areas? A glorified, expensive sewer!
The original tunnel and water containment project (Storm Water Master Plan – SWMP) was estimated to cost €438 million. It was meant to harvest rainfall to be used for agriculture and to recharge the aquifer. It was deemed to be too expensive. Can the people of Malta and other EU citizens (since they would have been footing the bill) be given a breakdown on how this estimate was arrived at? I can accept to be told that I am not qualified to question these costs but can an explanation to the public be given if we can use the following as a ‘yardstick’ for costs?
If we recall the tunnel linking Delimara power station to Marsa distribution centre conveying high tension electrical cables, the 8km tunnel cost €9.3 million – 40% of this cost was used to reinforce a 500-metre length of tunnel passing through unstable rock. It is simple arithmetic to work out that 7.5km of tunnel hewn in solid rock cost €5.6 million. That’s €0.75 million per kilometre of tunnel. Supposing that tunnel dimensions for the SWMP project are similar to the Delimara-Marsa tunnel, does this mean that the original (€438 million) project was going to create 580km of tunnels or 52km of tunnels in the case of the €40 million ‘sewer’ project? A justified question is “What is the cost per kilometre run of SWMP tunnels?” and “What is the difference between SWMP tunnels and the Delimara – Marsa tunnel?”
The person responsible for the National Flood Relief project explained (MaltaToday, 25 April 2010) “the main problem with reusing storm water is that it soon drains onto the road and becomes contaminated with sewage, oils and other dangerous materials”. This statement reveals that the plan philosophy was all about how to handle the waters once they collect in areas where they cause inconvenience – the roads. Even with half of the €438 million, is it possible that no means could be devised which could collect rain water from minor tributaries before they reach the contaminated streets and roads?
Roads take up less than 15 square kilometers. With rain falling onto the rest of the 350 square kilometers forming the Maltese islands must we contemplate to collect storm water after it reaches contaminated roads? 500mm of rainfall collected from a third of the Maltese territory is equivalent to all the nation’s water demands. Is sewage overflow not due to massive amounts of rooftop water being emptied into the sewer system after legal requirements controlling urban runoff and the collecting and storing of rainwater have been ignored for many years?
The biggest rainwater harvesting resource is the roofs of Malta’s substantial built up areas. There may be a plethora of ways in which rain falling on these roofs is drained away. The desirable scenario is that each property collects and reuses rain collected from its roof and maybe ever facades. Has the Malta Resources Authority documented what roof area of Malta’s buildings actually drains into wells, the size of the wells relative to the roof area, the use the property owners make (if at all) of the harvested rain, whether cisterns overflow regularly from over filling and where does the overflow end up (street level or drainage/sewer system)?
I suspect that nationwide, there is a substantial underutilisation or loss of rain falling on our rooftops, a loss we can ill afford.
A secondary system for collecting non-retained or unharvested rooftop runoff could be designed, the water collected regionally in communal cisterns where it can be treated for use as second class water for garden irrigation, some washing requirements and flushing units. The local storage, treatment and delivery from a water tower to the very buildings which collected the rain water in the first place, reduces energy demands because there is no need for pumping water around the island and demands for desalination are reduced. A portion of this harvested water would end up being eventually transported along as sewage for treatment.
Rain falling on rural and undisturbed land, make up by far the biggest potential area for harvesting rain which is untainted by pollutants found at road level in urbanised zones. Building dams in every valley may be an obvious way to retain runoff from valley slopes however there are two major disadvantages. The valley slopes themselves are often tilled land: flooding these is not desirable. Secondly, even if all the valleys could be dammed up with shallow dams, the potential for holding much rain runoff is not great.
There is however a way to increase rain water storage on valley floors without the construction of high dams and the flooding of agricultural land on valley slopes. Valley floors can be connected to tunnel cisterns excavated below valley floor level and running alongside below the ridges. If one assumes that rainfall is capable of naturally recharging the aquifer ‘unassisted’ to the tune of 15 million cubic metres of water a year, a further 20 million cubic metres of rain water needs to be harvested and allowed to reach the aquifer or to replace extraction from this source. A tunnel cistern system near valley floors with a capacity to hold around 8 million cubic metres of rainwater could drain into the aquifer or siphoned off from higher to lower elevations of utilisation sparing mechanical pumping. The tunnel system could be designed to store an aggregate of 20 million cubic metres during the rainy season. Tunnels similar in size to the road tunnels in Santa Venera with a tunnel face of around 50 square meters could be excavated. A combined tunnel length of 160km would need to be excavated, not necessarily interconnected. Even at twice the cost of the Delimara – Marsa tunnel, this system would cost around €250 million. This system would help to reverse the aquifer degradation, provide sustainability to revised agricultural practices and reduce dependence on desalination. Such a project would also generate large amounts of excavation material which must be utilised in some creative way and not simply discarded.
Whatever the details of the original SWMP project, water harvesting combined with efficient use of water in all sectors and actively seeking means of recycling as much water as possible are the most important issues which will determine if our dry island will support our children and our old selves in the decades to come. The funds have been made available this time when we have water in our taps. The funds will not be there when our taps run dry. The €250 million I mentioned would only be insufficient and ineffective if many fingers try to get into the pie!
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