Ground water extraction blamed for huge rise in soil salinity
James Debono
The amount of salt content in the Maltese soil has increased by a staggering 30% between 2002 and 2006, due to uncontrolled ground water extraction, MEPA’ State of the Environment Report reveals.
The accumulation of salts on or near the soil surface results in unproductive soils and the degradation of agricultural land.
Maltese soils are already vulnerable to soil salinisation, due to the proximity to the sea. But the State of the Environment Report concludes that “the main cause of salinisation is the use, for irrigation, of groundwater that is rich in salts.”
Malta’s ground water is becoming more saline because seawater is intruding into the groundwater sources, which lose pressure when too much water is extracted – usually through illegal boreholes.
The report shows how between 2002 and 2006, average soil conductivity (which indicates the level of salinity in the soil) increased from 581 μS/cm (micro Siemen per centimetre) to 756 μS/cm at the sites monitored.
The highest values were recorded in coastal areas, such as in Mgarr in the north of Malta, where in 2006 there was a concentration of 1,580 μS/cm.
“The fact that there has been an increase in soil salinity of 30% in only three years clearly indicates that we have a major problem with our aquifers on our hands,” hydrologist Marco Cremona told MaltaToday.
Cremona warned that if current trends persist, Malta risks losing a precious economic resource which yields 20 million cubic metres of free freshwater a year.
“We are on the road to losing them in a few years’ time because of lack of political commitment, regulation and poor or no water governance.”
Bristish geologist Gordon Knox has already warned that Malta’s water table could be “unusable” for irrigation some time between 2015 and 2025, because of the increase of salinity in groundwater from borehole drilling.
The increase in salinity of groundwater has seen more farmers investing in their own reverse osmosis plants, to remove salinity from borehole water.
The widespread use of RO equipment has increased energy costs for farmers, most especially after the latest hike in tariffs.
At present, there are around 8,000 registered boreholes in Malta and Gozo. A total 2,600 were notified to the MRA in November 2008 while another 5,400 boreholes had resulted from a similar exercise conducted in 1997.
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