Barcelona was ahead of the reality of drought episodes like the current one and just five years ago (in January 2018) it presented its first Action Protocol for Drought Situation. It contemplated reducing water consumption for irrigation of gardens and green spaces by up to 96% and consumption for urban cleaning (sewers and streets) by up to 97%. To a large extent, the key to these savings is based on a great treasure that the city has: groundwater from the city’s subsoil. A water that is not drinkable (due to the reduced extraction rate or because it concentrates salts or other elements) and is basically used to irrigate parks or for urban cleaning, precisely the uses that the exceptional phase due to drought prohibited this Tuesday by the Government, which have as an exception that the water is of phreatic origin.
“Municipal irrigation with groundwater is allowed only if it is verified through a hydrogeological evaluation that it does not imply a reduction in the availability of water for home supply”, specifies the chapter on exceptional measures of the Government Drought Plan. “The municipal uses that are made under the protection of the previous paragraph must indicate the origin of the water, clearly indicating that it is non-potable water,” adds the plan in a paragraph that is repeated in the case of water consumption for urban cleaning. The government of Mayor Ada Colau plans to detail this Wednesday what measures it deploys in the face of the current phase of drought.
Last year, those responsible for Barcelona Water Cycle SA (BCASA) —the public company that manages the sewage networks, the retention of river water, municipal supplies, beaches and ornamental fountains— assured that the municipal plan of the consistory in case of drought provides that 100% of these services use groundwater .
Between 20 and 25 cubic hectometres per year accumulate in the Barcelona subsoil (a quarter of the 90 hectometres consumed as drinking water). Of the total groundwater, which is managed by the Catalan Water Agency (ACA), the City Council has a concession of 4.4 hectometres per year and only 1.1 is used: a quarter of what it could. In 2018, when presenting the Drought plan, the Councilor for Climate Emergency, Eloi Badia, recalled that Barcelona has a groundwater network of almost 90 kilometers and that thanks to this infrastructure “the City Council manages to save drinking water for municipal services” . Some pipes connected to tanks and hydrants where water is loaded by vehicles that irrigate or flush.
In the case of some parks, the infrastructure comes directly, which makes it much easier to use. This is the case of those closest to the coast, between Ciutadella and the Fòrum. Parks like Central del Poblenou or Nova Icària, for example, are irrigated directly with groundwater. In other cases, it is reservoirs like the one below the Liceu, which allow areas such as Montjuïc to be irrigated.
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Currently, almost 100% of the water with which the sewage is cleaned comes from the groundwater; 80% in the case of street cleaning; and 18% of which is used to irrigate green areas. The councilor Eloi Badia usually affirms that the commitment to the use of groundwater is one of the life savers of the city. “We calculate that we will have 14% less water in the coming years. It will rain less and when it does it will be torrential. Our idea is to transform the city, use draining soils so that the water returns to the aquifer and that the use of groundwater by municipal services goes from 30% today to 100%”, he stated a year ago.
The draining pavements to which he refers are another key to the future. They are the so-called SUDS (Sustainable Urban Drainage Systems) that for a decade have been used every time new streets are built or undergo large redevelopment. Its porous composition is added to the conventional drainage of rainwater and allows the natural behavior of water to be reproduced in the city. Works such as the interventions in the four streets of the Superilla Eixample already incorporate it.
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