Mediterranean islands are looking at ways of better managing their freshwater resource. Most islands have specific conditions that are different from the continent and are generally marked by water scarcity, while much effort has to go into maintaining good water quality. Being tourist hotspots does not lessen the challenge they face.
Malta’s situation is critical, with average annual demand more than double what the aquifer can provide
A public consultation was held earlier this month as part of a project aimed at sustainable management of environmental issues related to water stress in Mediterranean islands. Partly financed by the European Regional Development Fund, the Mediwat project explores opportunities for increased inter-island cooperation involving regulators, technical people, academics and utilities.
The islands represented are Cyprus, Crete, Sicily, Corsica, Malta and the Balearics. A semi-arid climate, lack of surface water bodies and depleted aquifer systems are common factors for all the islands, putting their freshwater resources under significant pressure.
With water scarcity prevalent throughout, the islands have for the most part introduced similar management strategies such as a rising block tariff system to act as an incentive for more efficient use of water.
The scope of the project is to generate practical information, increase knowhow and promote water research in Mediterranean islands. Mediwat should lead to the development of a master plan for sustainable water management for each of the islands outlining what has been learned from a series of pilot projects.
Water policy needs to be integrated into other policies to ensure sustainable practices in agriculture, industry and other sectors.
The project will also assess water management tools from previous EU-funded projects for applicability at local level and make solutions more avail-able to policy and resource managers by means of an advisory web database platform.
Majorca, Cyprus and Malta are under particular stress, with their respective total water demands exceeding sustainable yield of their naturally renewable freshwater resource.
Compared to the other islands, Malta has its fair share of rain and is bettered only by Sicily in this regard. However, when population density is brought into the picture it is by far the most highly stressed island in terms of water quantity.
Malta’s situation is critical, with average annual demand more than double what the aquifer can provide without over-pumping beyond a yield level that can be sustained through natural rainwater replenishment.
This problem has been creeping up on us for years, and talk of how the aquifer could be artificially replenished is not new. In 1969, the first study was carried out on the idea of using treated sewage effluent to recharge the Maltese aquifer. It took another 25 years for the first boreholes intended to recharge the aquifer to be drilled in Malta. Uncertainties were still rampant and the technology not so well developed at the time.
Much progress has been made in the field of controlled replenishment of groundwater resources with adequately treated sewage effluent. At the same time, some new obstacles have surfaced.
Among these is the appearance of ‘emerging pollutants’. Recognised on a European level, these contaminants can be present in sewage in addition to the conventional pollutants of nitrate (from fertiliser) and chlorides (seawater intrusion) normally found.
Ten pilot projects under the Mediwat umbrella look at how both quantity and quality of water can be increased or improved while fine-tuning water management on the demand side. One such project in Sicily investigates the possible use of alternative energy to power a small desalination plant. Another Sicilian project studies various techniques to irrigate an orchard to compare the efficiency of the results.
The Corsica team considered reuse of treated waste water for fodder crops while assessing drift risks for pollutants. For irrigation purposes, further treatment of sewage effluent that has already undergone secondary treatment was the focus in Crete.
Paul Micallef, an engineer at the Water Services Corporation, spoke at the consultation on artificial aquifer recharge in Malta, which can take a number of different forms. These include infiltration ponds and dams, which allow water to percolate down to the aquifer and the collection of rainwater on rooftops to be directed into a well with a sandy or gravel bottom so that the water can seep into the water table below.
Aquifer storage, transfer and recovery involves injection via boreholes so that the stored water can then be drawn up from a nearby well.
Malta’s opportunities and limitations surrounding artificial groundwater recharge with highly polished treated sewage effluent (TSE) were discussed.
Making use of a Bulebel reservoir outside the ground-water protection zone, the Water Services Corporation and Malta Resources Authority have been testing the concept with water piped from the Sant’ Antnin purification plant.
Polishing before injection of TSE into the highly controlled test reservoir includes charcoal filtration, ultraviolet purification and reverse osmosis. The experiment is to determine long-term impacts along pathways of groundwater flow in the surrounding region. Three monitoring wells are fitted with probes.
Globally, many chemicals not previously considered to be contaminants are showing up in municipal, agricultural and industrial wastewater sources, and Malta is no exception.
Preliminary test results at Bulebel raised new concerns over these ‘emerging pollutants’. Apart from the ‘usual’ pollutants of nitrates and chlorides, further tests have shown that synthetic compounds from detergents and paint were found in treated sewage effluent from the Sant’ Antnin treatment plant.
Tests at nanogram level are to be run in laboratories abroad to determine whether emerging pollutants might present a barrier to aquifer recharge in Malta.
Even if safety can be assured, questions linger over economic viability. With highly polished treatment water not coming cheap, costs would rise even more if distribution had to meet more distant demand points across the island.
Manuel Sapiano of the MRA water policy unit (within the Ministry for Energy and Conservation of Water) pointed out that an increase in quantity of groundwater sourced from TSE could never be at the expense of water quality.
He pointed out that this is a basic requirement of both the EU water framework and ground water directives.
The resources authority will be conducting further tests while seeking assurance that aquifer recharge with highly treated sewage effluent can give consistent good quality results – and an adequate response timeframe if a problem arises so that users would be protected.
Planting of drought-tolerant crops is just one way to reduce demand on Malta’s water resource, yet it is difficult to implement as long as agricultural policy remains at odds with water policy.
The Malta Water Association has just launched its terms of reference for a national water plan. Political parties had already expressed their commitment after the association recommended a plan for integrated water management as a top priority.