In the summer of 2016 I thought it would be fun to share a post on Twitter about my quest to confirm the locations of different built infrastructure found on rivers in France. I asked Twitter followers whether the infrastructure in the satellite image I posted was a dam, or not. This was a question that I was working to answer for France, and also a question I had worked on for built infrastructure in other regions of the world too. My post caught a few people’s interest, and it soon was suggested that I share such posts on a weekly basis; this was the start of the weekly Twitter game that is predictably titled ‘#DamOrNot’. 


The first #DamOrNot tweet

Every Tuesday I share a satellite image, or an image from ground-level, of a waterway via my Twitter account, @ConnectedWaters. The image often includes obvious built infrastructure, like the image above where you can clearly see infrastructure crossing the river, but not always! Everyone following the #DamOrNot hashtag then has 40 minutes to share their guesses as whether there are built infrastructure in the image, what type of infrastructure are present, the potential changes and impacts these have had on the waterway and the people and nature that depend on the waterway. We then discuss the image, I do my best to identify the locations and types of infrastructure, and then share with followers why we are at the particular location, and discussing issues around this particular type of built infrastructure (or the implications of building or removing infrastructure). Each episode typically lasts about an hour each Tuesday, and I often take inspiration from current affairs and built infrastructure in news headlines around the world. 

The #DamOrNot game has been running on Twitter for 2.5 years. You might have thought that no one could find that many dams or other built infrastructure across our waterscapes, but we likely have 10s of millions of these intersecting our waterways the world over. For example, in the Great Lakes Basin of North America I have mapped nearly 300,000 different types of built infrastructure (dams, weirs, road culverts and bridges) intersecting rivers (Januchowski-Hartley 2013). This is why we here at FIRE Lab, our collaborators, and many other researchers are interested in identifying where these built infrastructure occur, determining their characteristics, and figuring out the changes that these bring to freshwater ecosystems and the people that depend on them. In France I was focused on first validating the locations of dams and weirs in an existing spatial database maintained by the French government, and then quantifying missing data on characteristics for those infrastructure (such as height – Januchowski-Hartley et al. 2019). In FIRE Lab, we are addressing similar research needs in the UK, and expanding on that previous work.

While #DamOrNot has been on Twitter for several years, a number of people have recently asked me to write about the game, who it is targeted at, to clarify the different types of infrastructure I focus on, and to offer some suggestions for beginners. In this first of two blog posts about #DamOrNot I’ll start by addressing the question about who the game targets, and offering descriptions, and where possible images, of the different types of built infrastructure we often encounter on the game. 

Q: Who is this game aimed at? 

A: Anyone and everyone. If you are interested in learning how scientists use remotely collected imagery from satellites, then this game is for you. If you are interested in learning more about infrastructure we have constructed on our waterways for centuries, and continue to construct, then this game is for you. If you want to refine your observational skills then this game is for you. I honestly started sharing these images because I found them so fascinating, and I wanted others to know about it and share in the fascination and learning with me. I was blown away by the level of detail of the Earth’s surface captured by applications like Google Earth, and that these are available not only to scientists but to everyone, and can be used to address diverse questions both across space and time. I believe my enthusiasm about this topic, and that of others who join in and contribute to #DamOrNot on a weekly basis, is what leads others to be interested and join in. 

Q: What are definitions for the different built infrastructure discussed on #DamOrNot?

The FIRE Lab team recently crafted descriptions for different built infrastructure that we are accounting for in our research, and this coincides with those that we often discuss on #DamOrNot. The descriptions are listed in the graphic below. 


Descriptions of common built infrastructure types discussed on #DamOrNot

While we can provide broad descriptions of these different infrastructure, the appearance and function of these does vary across the globe; that is part of the challenge faced in research into understanding how these infrastructure change freshwater ecosystems and associated processes (e.g., fish movement and migration).  Below are a few of the different infrastructure types as we see them on satellite or ground-level images. As you can see from the images below, some of the challenges that we face when trying to identify built infrastructure from satellite imagery is variable image quality across a waterway and the globe. Waterways with a width less than ~ 30 m can make it difficult to identify infrastructure because of surrounding tree canopy, and infrastructure can be hidden or difficult to differentiate from nature features like riffles. 


Common built infrastructure pictured in satellite images shared on #DamOrNot

In my post next week, I’ll offer some tips, often shared by myself and others in different #DamOrNot episodes, about how you can identify different infrastructure that we commonly encounter on satellite images, and the landscape characteristics that you can use to determine where we are on the Earth’s surface and what that means in relation to the #DamOrNot challenge. I’ll also dig a bit deeper to answer your questions about ‘how many people/countries/areas are impacted by dams’, ‘if this is increasing or decreasing’, and ‘is there a best dam – how does dam efficiency compare with like, letting fish through and the helpful ways dams can be designed to help the natural environment’? While these questions don’t necessarily relate to the portion of #DamOrNot where we work to identify different infrastructure, answers to these questions can help readers and followers to better understand why we are undertaking related research to gather data about these infrastructure and the changes they create for freshwater systems. 


Januchowski-Hartley, S. R., McIntyre, P. B., Diebel, M., Doran, P. J., Infante, D. M., Joseph, C., & Allan, J. D. (2013). Restoring aquatic ecosystem connectivity requires expanding inventories of both dams and road crossings. Frontiers in Ecology and the Environment11(4), 211-217.

Januchowski-Hartley, S. R., Jézéquel, C., & Tedesco, P. A. (2019). Modelling built infrastructure heights to evaluate common assumptions in aquatic conservation. Journal of Environmental Management232, 131-137.

3 thoughts on “Getting to know the Twitter game #DamOrNot (post 1/2)

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