With the aim of protecting the municipalities of Cabezón de la Sal and Mazcuerras from the floods of the river Saja, the project applies different strategies. One of the main actions corresponds to the execution of defence ditches along the flood plains. Once completed, they are treated with hydroseeding and/or tree plantations depending on their location. In their section, walkable, pedestrian, bicycle, etc. areas are integrated. The work on the banks also includes the elimination of longitudinal barriers (slopes) to help improve the profile of the river and mitigate the boxing-in effect, the planting of hydrophilic species such as willow to give stability to the banks, and autochthonous species on those slopes where the breakwater is eliminated. The aim is to make colonisation by invasive species more difficult. In those sections subject to greater erosion during periodic flooding, a Krainer wall has been built with ecucalyptus trunks and filled with natural material recovered from the construction site itself, a bed of willow seedlings and a breakwater footing. Finally, the recovery of historic branches of the river, on both banks, through the partial removal of defences and landfills that blocked its flow, stands out.
Mitigation of alien and invasive species. The treatment is applied over three consecutive years. Among the species present are mimosa, crocosmiala and, the most aggressive, reynoutria japonica. The work carried out with this species has covered an area of around 35 ha. Water quality. The design of the project takes advantage of the natural orography for the installation of hedges and green filters. This is a linear green infrastructure which, through its roots, manages to reduce the organic load from agricultural and livestock activities contained in the runoff and infiltration water. These green filters are placed on the banks of the streams that cross the meadows.
The regeneration of the river habitat is enhanced by the inclusion of measures to protect different species and promote biodiversity. Among the most significant measures developed in the project are those for the protection of birdlife, with the placement of insulators and anti-collision devices on the power lines in the area. River ecosystems are characterised by a high presence of amphibians, which are very vulnerable to habitat degradation. In order to promote the conservation of existing amphibian populations, 35 ponds have been built in which, in addition, refuges for phytophagous species (wood decomposers) have been incorporated. These refuges are made by placing wood bait from pruning in the area of the work.
As part of the social integration of the project, several dissemination and awareness-raising workshops have been organised for the nearby community during its implementation. The workshops held aim to increase knowledge about various aspects that affect the biodiversity of the project area. Workshops have been held on the construction of insect hotels (shelters), the construction and installation of nesting boxes for birdlife, the promotion of amphibians, the promotion of phytophagous species, the elimination of invasive species, the planting of native species, waste collection and the organisation of bioblitzs.