One of the cooler examples of hidden hydrology art in the past year is “Ghost Rivers”, the brainchild of designer and artist Bruce Willen of studio Public Mechanics.

Envisioned as a “…public art project & walking tour, rediscovering hidden streams and histories that run beneath our feet.” Willen uses traffic striping and signage to highlight multiple sites around the city, particularly Sumwalt Run, a buried creek that “now flows entirely through underground culverts beneath the Remington and Charles Village neighborhoods.”

The site includes some great background, including the history of the streams and their burial, along with some great illustrations of the path as it winds through

The installation itself is simple, using durable thermoplastic traffic striping in a wavy pattern that allows the line to engage with people in multiple ways and follow curbs and walks – so it is interrupting the linear flow patterns of walkers, cyclists, and driver throughout the city. This allows the eye and the curiosity to wander along these paths and connect the dots.

Self-guided walking tours are available and will expand as more sites are included, along with a Google map to track the route and key points. The signs are also simple, but bright and noticeable for those passersby, allowing for a bit of interactivity as they line up with the views of the meanders, and provide some background information and QR codes to scan for more engagement.

The summary statement explains the idea of connecting us with these hidden creeks.

“Below the streets of Baltimore flow dozens of lost streams. These ghost rivers still cascade from their sources, the many natural springs around the city. As the street grid sprawled outward from the harbor, these verdant waterways were buried in concrete tunnels. They now run deep beneath our rowhomes, channeled into the city’s storm sewers, hidden and mostly forgotten. You can sometimes hear their rushing waters echoing up from storm drains.”

The site also includes awesome resources for more information, history, daylighting resources, and other artistic interventions worthy of a follow-up, including a few I’ve posted about in the past and a few new ones. This is a model that is highly replicable in almost any city, using materials that are simple and evocative in unique ways to highlight those subterranean stories and make us reconsider our relationships with the hidden hydrology.

The idea is one of the most cohesive and elegant takes on the idea of revealing creeks using blue lines tracking the historical routing of the waterways. It draws upon precedents, mentioned by applying traffic coating, markers, or paint to mark the route of creeks, most similarly artist Sean Derry’s work in Indianapolis ‘Charting Pogue’s Run” and Henk Hostra’s “The Blue Road” in Drachten, The Netherlands, the proposed “Ghost Arroyos” in San Francisco. Another art-based example from Baltimore is the “Green Alley” street painting, and more loose, ephemeral versions in the St. George Rainway in Vancouver, B.C., in São Paulo, Brazil as part of the Rios a Ruas project, Stacy Levy’s Stream Sketches in New York City.

There are lots of examples of this type of project, and it is interesting to see the different ways a simple blue line can be used to engage in revealing historical layers. So let me know if you have other favorites you’ve seen.

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Note: This post was originally posted on Substack on 04/29/24 and added to the Hidden Hydrology website on 04/23/25.