Demolition of Valverde Dam in the Bullón River, in Frama, Cantabria, Spain

Introduction

The Bullón River is a 23.8 km long river that rises at an altitude of 1,600 metres in the Sierra Peña Labra in the province of Palencia. However, it flows almost entirely through Cantabria until it flows into the Deva River as its main tributary.

It is worth noting that it is located in a habitat protected by the Natura 2000 Network, ZEC Río Deva ES1300008, and also borders the ZEC Liébana ES1300001.

At the national level, it is part of the Fluvial Nature Reserve, a protected area due to its great natural and scenic value, and is a representative example of Cantabrian-Atlantic rivers.

It is an isolated and inaccessible river environment. Its headwaters have gradients of over 10% and gentler gradients in its mid-lower reaches, where the Valverde dam is located in Frama.

It contains key species such as Salmo salar, Petromyzon marinus, Salmo trutta, Lutra lutra, and Alcedo atthis.

Project context and opportunity

This demolition aims to continue the work of four other dams already removed, with the goal of improving the longitudinal connectivity of the Deva River basin’s river network by addressing a disused and abandoned dam.

This project is also a follow-on grant from a pre-demolition grant previously awarded by the Open Rivers Programme.

With this experience and knowledge, the project team intends to continue removing obstacles in this basin. Hydraulic infrastructure constitutes a significant group of obstacles that disrupt river continuity in this basin, as its presence fragments the river ecosystem and alters the flows of water, matter, and energy, as well as the movement of aquatic fauna, reducing their distribution area.

The European Biodiversity Strategy calls for a focus on obsolete barriers that no longer serve their original purpose or are no longer necessary. This project will contribute to this objective because it meets all these criteria and is undoubtedly the most appropriate alternative for fish species and natural river dynamics.

Project aims

The ultimate goal is to demolish the Valverde dam in Frama and restore and improve river connectivity by opening 24 kilometres of interconnected rivers between the Bullón River, the main tributary of the Deva basin, and the Aniezo and Lamedo tributaries. This will improve biodiversity, hydromorphological functioning, and sediment dynamics. Furthermore, it will enhance the physical characteristics of the habitat, such as water velocity, substrate, and refuges.

The expected outcomes are:

1. To contribute to creating an environment of acceptance and support for the project and its objectives.
2. Foster critical thinking among key local stakeholders regarding the need to restore and improve river connectivity.
3. Report on the results of electrofishing catches.
4. Signing of the contract and the occupational health and safety plan.
5. Complete report on the demolition of the Valverde weir, including the development and execution of the work and all accompanying graphic documentation.
6. Official certificate of completion of work, signed by the project management and the contractor.
7. Report on the environmental monitoring, follow-up, and surveillance programme, reflecting the knowledge gained and the improvements made to the Bullón River and its riparian forest.