Case study:Robledo de Chavela dam removal

From RESTORE
Jump to: navigation, search
0.00
(0 votes)


To discuss or comment on this case study, please use the discussion page.


Location: 40° 30' 18", -4° 14' 4"
Edit location
Loading map...
Left click to look around in the map, and use the wheel of your mouse to zoom in and out.


Project overview

Edit project overview
Status Complete
Project web site
Themes Social benefits, Water quality, Urban
Country Spain
Main contact forename Rincón Sanz
Main contact surname Gonzalo
Main contact user ID
Contact organisation
Contact organisation web site
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No
Moment of the demolition of Robledo de Chavela dam. The first photo shows the dam before its removal. The second picture shows the demolition moment and the third the state of the dam after demolition. Photo Credits: Ministry of Agriculture and Fishing, Food and Environment (MAPAMA).

Project summary

Edit project overview to modify the project summary.


The removal of the Robledo dam was a milestone as to be the highest dam demolished in Spain, and possibly, in Europe.

The work carried out, besides the removal of the dam wall, consisted of the extraction and relocation of sediments, the capture and transfer of 4500 specimens of native fish, delimitation of the channel with riprap, slope profiling and reforestation of the riverbank.

The dam was demolished on September 29, 2014, by the use of 1.2 tons of explosives. More than 9,000 m3 of concrete from the wall of the dam were demolished.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.


Due to the problems of sediment contamination stored upstream of the dam, a study was carried out prior to the removal in order to make a diagnosis of the sediments and their treatment. A plan is implemented to remove some of these sediments and place them in higher areas where they were confined and stabilized by planting native vegetation. Two years after the removal of the dam, a monitoring plan was conducted to measure:

- Physicochemical parameters of water as temperature, dissolved oxygen,

conductivity and pH.

- Habitat availability.

- Quality of the riparian forest.

- Flora (macrophytes) and fauna (macroinvertebrates and fish) present in the river, as well as exotic species.

The fish community in the Cofio River near the Robledo dam is: Rainbow trout (Oncorhynchus mykiss), Iberian barbel (Luciobarbus bocagei), chub (Squalius pyrenaicus), calandino (Squalius alburnoides) and Iberian gudgeon (Gobio lozanoi), being Squalius alburnoides the dominant specie. All are native species of the Tajo River Basin except from the rainbow trout that is exotic and comes from sport fishing.

Sampling points were determined both upstream and downstream from where the dam was located. The main results of this monitoring show clear signs of recovery in the river reach affected by the presence of the dam, with some differences between the areas that were located upstream and downstream of the dam.

Lessons learnt

Edit project overview to modify the lessons learnt.


The removal of the Robledo dam stands out as an example of participatory management, in which the importance of administrative coordination between different social agents is evidenced.

The Robledo dam removal will promote the recovery of altered river processes as a consequence of the construction, exploitation and abandonment of the dam. It will therefore contribute to the improvement of the ecological status of the Cofio River and the native fish populations in this river.

A monitoring program was carried out after the dam removal (in August 2016) showing environmental improvements in the river after the removal. The importance of performing this monitoring before and after the dam removal is emphasized in order to quantify the effects that this type of actions have on the river.


Image gallery


ShowHideAdditionalImage.png


Catchment and subcatchment



Site

Name
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body No
National/international site designation
Local/regional site designations
Protected species present No
Invasive species present No
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category 0.1 - 1.0 m³/s
Mean annual discharge (m3/s) 0.75
0.75 m³/s
750 l/s
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m)
Project started 2014/09/29
Works started
Works completed
Project completed 2014/09/29
Total cost category 100 - 500 k€
Total cost (k€) 280
280 k€
280,000 €
Benefit to cost ratio
Funding sources

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design
Stakeholder engagement and communication
Works and works supervision
Post-project management and maintenance
Monitoring

Supplementary funding information

There is a total budget of €1.5 million which includes the elimination of the dam and the renaturalization of the environment.



Reasons for river restoration

Mitigation of a pressure Barriers to fish migration
Hydromorphology Continuity for organisms, Continuity of sediment transport, Quantity & dynamics of flow
Biology Fish: Abundance, Fish: Species composition
Physico-chemical
Other reasons for the project Heavy metal pollution & This dam has never fulfilled the purpose for which it was designed, So the only management option, for technical, safety and environmental reasons, was its removal.


Measures

Structural measures
Bank/bed modifications Dam removal, extraction and relocation of sediments, Delimitation of the channel with riprap, slope profiling, Reforestation of the riverbank
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions Capture and transfer of fish
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative


Monitoring documents



Additional documents and videos


Additional links and references

Link Description
http://europe.wetlands.org/publications/river-fragmentation-analysis-spain/ A link on the Wetlands International website to a document that describes the project.
http://www.ecohidraulica.com/ All information on this page is copied from the document mentioned above which is written by Ecohidráulica, S.L.

Supplementary Information

Edit Supplementary Information

References

Amor Cortés, J. (2016). Emisiones de gases de efecto invernadero en la demolición de la presa de Robledo de Chavela y la restauración ambiental de los terrenos afectados. Final Master Degree dissertation.

Confederación Hidrográfica del Tajo (2009). Diagnóstico y Propuesta de Tratamiento de los Sedimentos del Embalse de Robledo de Chavela en el río Cofio (Madrid). Estrategia Nacional de Restauración de Ríos.

Confederación Hidrográfica del Tajo (2014). Derribada la presa de Robledo de Chavela (Madrid), sobre el río Cofio, la más alta desmantelada en España con casi 23 metros de altura. Press release from 29/09/2014

Confederación Hidrográfica del Tajo (2016). Seguimiento del estado ecológico del Río Cofio tras la demolición de la presa de Robledo de Chavela.

Headwaters Economics (2016). Dam removal: case studies on the Fiscal, Economic, Social and Environmental benefits of dam removal.

Industrial Economics Inc. (2015). Economic & Community Benefits from Stream Barrier Removal Projects in Massachusetts (MA). Massachusetts Department of Fish and Game, Division of Ecological Restoration.

Ollero Ojeda, A. (2015). Guía metodológica sobre buenas prácticas en restauración fluvial. Manual para gestores.