Dam Removal Europe webinar

Today I tuned into a dam removal webinar hosted by Bart Geenen. More than 400 people worldwide joined river scientists and interested people on this webinar all about the impacts of dams and benefits of removal on fish migration.

Pao Fernández Garrido from the World Fish Migration Foundation gave a summary of how dam removal has progressed so far, demonstrating Dam Removal Europe (DRE), a partnership between 7 organisations including WWF, World Fish Migration Foundation, the Rivers Trust and Rewilding Europe.

Bob Irvin from American Rivers was also on the call, and mentioned he was pleased to be part of this, and celebrate today’s dam removal, as well as the growing dam removal across Europe. He mentioned how with every dam removed a river is restored for the fish, people and generations to come.

We then had a presentation from the UK, as Jack Spees, Chief Executive of the Ribble Rivers Trust talked about the importance of getting local people involved in restoration works, for example volunteers to tackle non-native species.

We then moved to France were Stéphane Jourdan gave his presentation on feedback from dam removal in the field.

Following some questions we went live to Sweden, were Esa Fahlén and his team were answering questions bankside, on a dam removal site! Esa interviewed Ula, a university researcher and biologist working on fish migration and solutions from fish passage. He mentioned how projects usually focus on providing upstream passage for large salmonid fish and trout, but this has progressed to more technical fish. There has been a shift of target species from salmonids to all naturally occurring fish species, and dam removal will be hugely beneficial. Ula’s task is to evaluate the effects of removal, focusing on fish passage before and after removal. The main species will probably be salmon in combination with eels, however dam removal can have beneficial impacts on lots of different species.

Dam removal in Sweden as a restoration tool is quite new and not very common. Most work has been looking at downstream and upstream passage and habitat restoration. They mentioned that they never thought this kind of technique would happen in Sweden, as they rely heavily on hydropower for electricity.Sweden have removed a lot of small barriers and structures, but not so many dams.

Dam removal in Sweden has always included voluntary engagement of landowners, and co funded by the owner as well as national funding. Whether or not dam removals in the country will increase is the million-dollar question! Legislation has recently been formally approved so that all hydropower plants in Sweden have to be relicensed. Older permits were under the old water law, so needed to be updated. With increasing restorative works in the country’s regulated rivers, it is likely more removals are to come.

All the contractors and researchers on site are happy to see this work being carried out today. It had been planned for several years, and the removal is good news for the fish! This project helps improve knowledge. When you know how devastating a dam can be, it is important to see the change and beneficial impacts of removal.

Following this interview on site, Andrea Lundblad presented on her work to remove barriers. She owns a small company aiming to make the world better for aquatic fauna (Naturentreprenad Syd AB). Andrea stressed her key values, including that as much funding as possible should be invested into the actual removal/enhancement works; landowners should be involved as much as possible; and we need to act now.

One of Andrea’s examples was a 1m high overflow weir with a salmon fish ladder installed. The barrier needs to be amended to make it passable to all species, however there are heritage issues. The surrounding wall has cultural values and needs to be preserved, but the river is eroding and the wall is going to fall into the creek. The solution was to open part of the dam and build up the creek bed with gravel and blocks to support the wall and slow erosion.

There was then time for some questions. One of the recurring queries from the 400+ participants was the ability to predict sediment erosion after removal of weirs/dams. This is when Laura Wildman dialled in from the US, providing comments on models and guidance for sediment. Conceptual models are best for dams. You need good data, potentially using sediment probes, and determine what the equilibrium slope is. You need to predict what is going to become mobile, what is not going to mobilise, and how the system is likely to respond. If further models are needed, advanced hydraulic sediment models are suggested.

Laura mentioned how removing a dam is always exciting, and the ability to restore a river to its natural processes is pretty amazing! She talked us through a project on site, where an old mill dam is being removed in a few weeks, as it has fallen into poor condition and not meeting safety codes. Repairing the dam would have been significant as it would have to be completely rebuilt to meet today’s standards, plus removal of the dam is not as expensive.

The designs and plans have been finalised and work has already been carried out to dewater the channel, providing a good feel for what the channel will look like after dam removal. The dam provides lots of aesthetic value, so part of the dam will be left in place, whilst part will be taken out to let the river run free and allow species such as eel to pass.

Laura was asked what is the first thing to look for at a site. She provided some really good tips including:

• Access and how machinery will get to site
• Assess the condition of the dam and what its current uses are
• Assess the quantity and quality of sediment mobility, and consider whether sediment needs to be taken off site or to another location on site
• Determine any flooding or ecological problems downstream
• Local infrastructure
• Regulatory resources such as wetlands, threatened and endangered species
• Consider the composition of the dam material e.g. sheet piling

Finally, Laura mentioned some things that will be difficult to know before the day. For example, she mentioned projects when they came across undocumented pipes, cannon balls and cars instream! Concrete preserved underwater can sometimes be very strong, and you shouldn’t underestimate the amount of time needed to remove the dam, i.e time to break up the material. She suggested swamp mats (steel or timber mats to get the equipment out to spots that are challenging to get to). She stressed the importance of preparing for the worst weather such as a downpour or hurricane. Good protocols, precautions and technical specifications are vital.

We then went back on site to Sweden, where more stakeholders were interviewed about the dam removal. Interviewees included Secretary General of a river association, Environment Manager for Hydropower in Sweden, and the Site manager for dam removal representing the angling community.

You all represent different organisations. Do you have different perspectives on dam removal?

• Although hydropower is beneficial, this plant removal is showing it is also important from an ecological view, and benefits the river itself.
• This removal is beneficial for anglers. This is in the middle of their fishing area, so taking it out opens up fishing opportunities.
• One thing that has been useful is the long history of collaboration with these partners, which makes everything easier.

What are the reactions from locals and landowners?

• Some are concerned about what will happen afterwards, but they have been involved in the process from early stage. If there is a risk to their real estate, they have been compensated.
• Some are afraid of water supply shortage, or if the river will become a muddy ditch, but never seen a case of that. People like to see a pretty picture of what the river will be 2 years, for reassurance.

What expectations or hopes do you have from this removal?

• Hope to restore the river to former conditions before the power plant, and enhance habitats.
• Hope to learn from this project and know more about how to carry out this project, and understand the response of the ecosystem.
• The local village is built up around fishing, so it will be interesting to see what social economic effects there will be in the future
• Good to see free flowing river rich in biodiversity.

Are there any fears that invasive species will colonise upstream?

• No, this dam has had a fish pass on already so not been totally closed, so shouldn’t be a problem here, but elsewhere this is something that should be considered.

What are your tips for first steps for dam removal?

• Need to involve all stakeholders
• Apply for appropriate permits, connected with different conditions for protecting the environment.

Are there any issues with cultural or heritage values?

• We always need to consider this when applying for permits for dam removal. No one wants to destroy cultural heritage, so need to remove barriers with care and think about history.
• This can sometimes complicate things and make things more expensive.
• If the stream is a protected area, this is usually written into the policy. We need to protect, preserve and improve nature where we can, and dam removal can drive the process.

How did you plan for the lowering of water surfaces before dam removal?

• This has been done over 5-6 weeks to ensure species are not stranded or trapped. We have also lowered turbidity at the reservoir. We don’t want to destabilise river banks. When water pressure disappears, banks could destabilise if this pressure reduction is not controlled. Levels have been lowered slowly so species have time to adjust and move. Mussels climb down and have been monitored by a mussel expert who moved them. Most moved by themselves so this wasn’t a problem.

Finally, Esa showed us around the site virtually! We saw all the plant and contractors working on site to remove this barrier. It was great to see science meeting practice in the field. It really felt like we were part of this removal and in the field!

Just before the close of the webinar, Franco Campos-Lopez gave us some great news. He is making a film on dam removal intended to feature river heroes around the world. The video follows Pao from World Fish Migration Foundation, as a scientist looking at every continent and dam removal. We hope to see more people engaging around the world, and feature things/stories that inspire.

Watch the trailer

Thanks to everyone involved in running this informative, engaging, interactive webinar, all about connecting rivers and connecting people. It has been great to hear from so many perspectives from across the globe, all working towards the same shared goal of fish migration and river restoration.