This removal will improve the water quality and Water Framework Directive Status of the stream, bringing positive effects for the conservation of native fish, amphibians and mammals.
Flowing within the Tagus Catchment, the Perofilho Stream is a short, 6.6 km long, tributary of the Tejo River. It flows into the hydrographic Rio Maior basin, in a river locally known as Azambuja River or Rio Maior.
The Perofilho Weir is within private land belonging to the SOS Animal Association. The land was acquired recently by the association, and the association aims to realise beneficial environmental projects there. Important freshwater biota has been observed along or near the Perofilho Stream inside the property, such as the migratory and critically endangered eel, the Eurasian otter, and the Iberian painted frog.
|Km to be opened
|European eel, Eurasian otter, Iberian painted frog
|Dam removal (demolition)
This weir removal project arose thanks to the strong relationship between ANP|WWF, the local municipality, and the land owner. Such good political and local support is expected to boost advocacy for dam removal nationally. Moreover, the relevant ecological benefits of removing this weir, such as habitat recovery for eels and otters, will continue to strengthen dam removal advocacy over time. The project team is also eager to conduct fish sampling in the stream to detect other fish species of conservation concern.
This removal will improve the water quality and Water Framework Directive Status (currently listed in in Poor state) of the stream, bringing positive effects for the conservation of native fish, amphibians and mammals. It will restore fluvial connectivity for 2,5 km of stream (almost half of its entire course) and potentially more, improving the connectivity between this river and the lower stretches going into the Tejo River. This demolition could also pave the way for other barrier removals in the same stream and in the Tejo Catchment (in total from the Perofilho Weir up to the confluence in the Tejo River it is 34 km), improving habitat for several autochthonous fish species present in the Rio Maior hydrographic basin.
In addition the project will result in the first research into fish species in this stream. Recently, an eel was observed downstream of this barrier, indicating the presence on this critically endanger migratory fish species. Fish monitoring through electrofishing and/or fish nets and eDNA collection will allow the project team to collect more robust data, creating a better understanding of local fish populations and documenting possible improvements in fish and macroinvertebrates abundances after the removal. In particular, possibilities will be sought to perform a citizen science project focussed on eels in this river and possibly the whole Tejo Basin.