This week, Diane posted about the newest Ottawa-Gatineau open-water swim spots. If you missed it, you can check it out here. I’ve always been attracted to the idea of swimming in an urban environment. It feels adventurous and a little subversive. You are in nature, but also adjacent to architecture, machinery, roads, cars– all the features of the modern city.

This is no news to European city dwellers, who have their choice of open-water swim spots that have been designed for ease of access and are monitored for safety. The New York Times did a splashy (forgive the pun) spread featuring several of these swimmable cities, which you can see without a paywall here. I can’t resist sharing some of their photos below.

One of my fantasy vacations would be to do an open-water European swim tour. All I’d need would be my Speedo, a towel, and a public transport pass. Imagine that.

In the US, there are loads of lovely wild swimming spots in national and state parks and also more out-of-the-way but well-known-to-locals spots. I’ve enjoyed refreshing dips in Black Creek in Darlington, South Carolina and Oak Creek in Sedona, Arizona, to name a couple. Our friends at the NYT also covered cool US wild swimming holes are here.

However, if urban open swimming is what you’re looking for, the US is not the best place to find it. There are a handful of city beaches in coastal cities, and some places organize open-water urban swim events, but in general, access to urban waters is not legal or reasily accessible or safe here. Boooo…

In Boston, my hometown, there’s a yearly event called CitySplash, where people can sign up for a time slot to jump into the Charles River from a dock and paddle around with other enthusiastic urban swimmers. Some years, however, the bacteria levels are too high and the event gets canceled. I blogged about my own CitySplash experience here.

The dedicated people at the Charles River Conservancy have big plans to transform parts of the urban riverscape to allow swimming and splashing for people of all ages and swimming abilities. Here’s a rendering of what they envision, with public transport access, shallow and deep swim areas and places to hang out.

But it’s certainly not happening this week. Intermittently this summer, the Charles River has been the site of a cyanobactera alge bloom. And this week, that bloom expanded. You can see it below.

The Cambridge public health department explains more here.

Algae and cyanobacteria (also called blue-green algae) are plant-like organisms that live in water. They can quickly grow out of control, or “bloom.” Some of these blooms produce toxins (poisons) that make people and animals sick. If you, your child, or your pet comes in contact with the water, rinse off immediately. Contact can cause skin and eye irritation, and inhalation or ingestion can cause respiratory irritation and other illness. If the blue-green algae are producing toxins, the health effects can be serious.

Practically speaking, cyanobacteria blooms mean no swimming, boating, paddleboarding, or fishing in the affected areas. Pets should be prevented from drinking the water, as it is harmful to them, too.

What causes these bacterial infections of our urban waters? A bunch of things, including pollution, runoff from hard rains, and increased temperatures. You can read more about it on the Environmental Protection Agency’s website here (which still mentions climate change, miraculously– don’t tell anyone…)

This is a pretty big problem for the planet, the environment, our water supply, and also our access to the joys of urban swimming. There are some things we can do to mitigate and respond to the causes, and I hope we can claim and reclaim some spaces in our cities for swimming and splashing.

Readers, have you done any urban swimming? Where was it? How was it? I’d love to hear from you.