Hydroelectric plants Limnological control of the most eutrophicated reservoirs in the Tagus basins (pollutant loads contributed by agents unrelated to Iberdrola that travel along these rivers before they flow into the reservoirs) Prevention of potential impacts on fauna located downstream of the reservoirs Construction and waterproofing of tanks and drums; replacement by dry transformers; septic-tank reinforcement; oil separators; replacement of lubricating oils with less polluting substances; maintenance and adaptation of spill-containment systems, etc. Prevention of pollution and of its potential effects on flora and fauna.