Removing the “Presa del Henares” weir to benefit nature and people

Covering all the preparatory work needed to remove an obsolete weir on the Henares River in Madrid, Spain.

Introduction

The Presa del Henares weir was built in 1863 to provide water for the irrigation fields of Mejorada del Campo and is the largest weir of the Henares River. However, this very steep weir is obsolete, and both the barrier and the channel are in very poor condition. Removing it would enhance the river’s natural dynamics, something rare in Madrid region rivers, which could reduce the area impacted by future floods. Removing this weir will free up around 35 km of the Henares River improving its connectivity, restoring natural river dynamics and boosting biodiversity within a Natura 2000 area. The weir is located within a protected Regional Park, a Special Area of Conservation, a Special Protection Area and a Madrid region protected wetland.

At a glance

Project typeDam removal: pre-demolition
Project statusLive
CountrySpain
RiverHenares
Km to be opened35
Focal speciesseveral endangered, threatened or important species of birds, mammals, fish and reptiles
WebsiteWWF Spain

Project context and opportunity

The weirs close proximity to Madrid means that several million people will benefit from the increased conservation value, improved recreational opportunities, and potential for environmental education. Removing the weir will also boost efforts to remove the other obsolete barriers on the river.

The removal of the Presa del Henares weir has a high probability of success since we have strong partnerships with the Environment councillor of Mejorada del Campo and her team, who are committed to improving the environment within the municipality, the Water authority of the Tajo river basin, and the regional government of Madrid, which has the competences for protected area management. They are supportive of this removal and have taken steps to facilitate the removal of this weir by (1) including it in the catalogue of the Water Authority of the Tajo river basin of obstacles that should be demolished, and (2) not renewing its expired irrigation concession.

The role of WWF will be key to catalyse the demolition facilitating the process. The water quality in this section of the river is good so increasing the connectivity will definitely boost biodiversity and contribute to reduced flooding.

Project aims

The project covers all the preparatory work needed to remove an obsolete weir on the Henares River in Spain, through the elaboration of a weir removal project that have as main goals:

  • Increasing the river connectivity that will definitely boost biodiversity and removing the weir would contribute to reduce flooding. In addition, it will help to restore the river’s natural functions and key ecosystem services, such as water purification.
  • Establishing technical specifications needed to remove the weir and restore this stretch of the river, taking into account other conservation and restoration activities in the area.
  • Contributing to improving the ecological status of the river. It will enhance both water ecological status and conservation status of aquatic habitats and species.

Partners

WWF Spain