portada de BMM

by Antonio Cerrillo

The inhabitants of Barcelona have learned how to turn off the water tap. The year 2000 marked a new record in the reduction in household water consumption in the 23 municipalities that comprise the metropolitan area serviced by the "Aguas de Barcelona" company. Teps suffering, the last of which took place in 1999. The real achievement which that water-saving effort constitutes - taking into account that we are referring to a natural resource - has nevertheless been tarnished by an increase in water consumption rates within Barcelona's greater region (a region which comprises about one thousand municipalities that stretch from the Montseny inland area to the Garraf coastline) as well as in the whole of Catalonia. The decrease in household water consumption started at the beginning of the nineteen nineties after the first water-saving campaign (which had been launched as a result of the particularly severe drought of the previous year) and the introduction of a new kind of water bill that put up the price of the service in order to penalize high consumption rates.
Nonetheless, the decrease is water consumption during 2000 was of merely 1 per cent, and most experts are convinced that household consumption rates cannot possibly be reduced much further because current figures are already reasonable enough and the effects of the public campaigns will necessarily become weaker and weaker with the passing of time. Whereas this phenomenon is particularly noticeable in the urban central area (Barcelona, Santa Coloma, L'Hospitalet), the localities within the outer metropolitan area (located outside the 23 municipalities serviced by Aguas de Barcelona) are already showing an increase in water consumption. The reason for it is the expansion of a town-planning pattern based on single-family detached or semi-detached houses with a garden, which entails a very intensive use of water (garden watering, household appliances such as washing machines and dishwaschers, showers and, in some cases, swimming pools).
In Barcelona's metropolitan area, the drinking water supply comes from water-catchment systems in the Ter and Llobregat rivers, whose flows are subject to fluctuations at low-water times. In the first case, the water stored in the Sau and Susqueda reservoirs is carried to the purification plant in Cardedeu and later supplied to Barcelona through the Trinitat water tanks. And, in the case of the Llobregat river, waters are harnessed in the area close to Sant Joan D'Espí to be later distributed to the houses through the urban piping network. A third "tap" can be found in the subsurface flow of the Llobregat river, a strategically important water reserve that can now be used - even though in limited quantities in order to prevent overexploitation - thanks to the wells dug by "Aguas de Barcelona". We could even make use - in fact, it is already happening in extreme circumstances - of the purification plant located in Abrera which is connected to a large duct that is supplying water to diverse municipalities within the Llobregat valley.
The central problem affecting water supply within the area of Barcelona is the periodical episodes of drought which deplete the water reserves from the Ter and Llobregat rivers at some times of the year and can even hold a threat over the whole service. The availability of a double "tap" (i.e. the Ter and Llobregat rivers) allows the administration of the water supply service some margin for action as they can use one or the other according to the amount of water stored in the different reservoirs at any given time; nevertheless, there have been times when the area was running critically low on water supply. As a matter of fact, between 1998 and 1999, the Catalan "Generalitat" autonomous government implemented a decree that included diverse measures to combat drought, such as a reduction in the amount of water piped in from the reservoirs and other actions intented to save water in the city by regulating its consumption for watering parks and gardens, cleaning streets or ornamental uses (fountains). No restrictions on household consumption have had to be imposed yet, but this is an ever-present possibility which deeply concerns the Catalan water supply administration.