1.1.1.WATER RESOURCES Despite the relatively low rainfall and the arid appearance of the Maltese Islands, local catchment characteristics are very favourable for the storage of rainwater and the hydrological cycle provides a generous supply of freshwater which undoubtedly contributed to the early settlement of the inhabitants. Surface water resources Total surface water resources are estimated at 0.5 million m³/year. Structurally, Malta tilts gently to the east giving rise to a topography that is high along the western shores and gently slopes down to sea level along the eastern shores. This implies that the surface drainage lines cross the entire width of the island from their source close to the western shore before reaching the sea on the east. This favourable topography, combined with the good water storage capacity of the soil, excellent infiltration characteristics and effective runoff interception by numerous dams and cisterns, gives the surface water maximum time to seep into the ground and thus minimizes runoff losses to the sea. A greater amount of surface runoff, however, is lost from urban areas via sewers or directly to the sea especially in coastal towns and villages. Attempts are in hand to tackle the storm water wastage problem for a more effective use of surface runoff. Morphologically, the Maltese Islands are divided into two main units by the Victoria Lines fault that crosses the northern part of the island of Malta from west to east. North of this fault, Malta is broken up into a number of horsts and grabens by less pronounced faults. Drainage is parallel to the general strike of the horst-graben system and the few intermittent streams flow into the bays to the northeast. The second morphologic unit lies south of the Victoria Lines fault, where two main drainage systems are found. The main one converges into the Valletta basin by a system of east- or northeast-trending streams, while the second one converges into Marsaxlokk bay to the southeast. The renewable groundwater potential on the Maltese Islands is estimated as being approximately 40 million m³/year. In order not to deplete the storage capacity of the main aquifer without causing salt water intrusion, only 15 million m³/year of groundwater would be potentially extractable. Based on the 1995 figures of the Water Services Corporation, however, 19.75 million m³/year were extracted from 13 pumping stations, approximately 160 boreholes in Malta and Gozo, and about 2,800 registered private wells (the latter extracting an estimated total of 2.44 million m³/year). This means that groundwater depletion does in fact take place. Moreover, there is significant extraction from illegal and unregistered wells (probably up to 2.97 million m³/year), leading to a total groundwater extraction of 22.72 million m³/year. Most runoff occurs after heavy torrential rain. This is the only time when surface water flows, for a few days at most, along the beds of the major valleys. To retain this storm discharge, a large number of small dams have been constructed across the drainage lines. They also serve the purpose of reducing the rate of soil erosion. Open reservoirs have been constructed along recently made roads to minimize runoff. Total dam capacity is estimated at 154,000 m³. At present 31.4 million m³/year of desalinated water are being produced from four sea water Reverse Osmosis Plants and one brackish water Reverse Osmosis Plant, but this is a rather expensive procedure. In 1993, of the total produced wastewater estimated at 23.7 million m³, about 1.82 million m³ was treated and 1.56 million m³ of this was reused. Total water withdrawal was estimated at 55.68 million m³ in 1995, of which 87.3 per cent was for domestic purposes (11.9 per cent is withdrawn for agriculture and 0.8 per cent for industrial use). Of the total quantity of groundwater used (22.72 million m³), 17.2 million m³ were used for domestic purposes, 5.41 million m³ for agricultural and the remaining 0.11 million m³ for industrial purposes. The desalinated water (31.4 million m³) was all used for the provision of potable water in the public supply, which is equal to 65 per cent of the total potable water supply. Of the total reused treated wastewater (1.56 million m³); 1.22 million m³ was reused in agriculture and 0.34 million m³ in industry. In Malta, as in most Mediterranean countries, water is a scarce, over-exploited resource and desalination of seawater needs to be employed to meet demand for households and industry. Through its national legislation, accession to the European Union and other international commitments (such as the Barcelona Convention), Malta is committed to ensuring the sustainability of Malta's water resources in a holistic manner (Malta Environment & Planning Authority). Water scarcity exacerbated by intensive human activity on a small land area is the main problem of Malta with limited natural water resources.

(Water Risk Filter)