Nereda 2: a Hydromancy

HD, colour/audio, 06’30”, 2024. Produced with the support of EU Creative Europe, HKU Utrecht (The Netherlands), Hydromedia.org. Audio recorded at the HDSR waste water treatment plant at Overvecht (NL).

Hydromancy { ὑδρομαντεία 
 ~ the supposed art of divination by water

The Persians, according to Varro, invented it; Pythagoras and Numa Pompilius made use of it; and we still admire the like wonderful prognosticators.

Encyclopedia Brittanica, 1797.

In the science fiction film ‘Arrival’ (Villeneuve, 2016), linguist Louise Banks is assigned to establish communications with alien beings that have appeared in large, monolithic vessels that hover silently above various locations on Earth. She is called in to help the military understand whether this visit is friendly or a threat. In one scene, Banks, cloaked in an oversized hazmat-suit, walks towards these otherworldly beings while holding up a handwritten sign that states ‘human’.

The idea that other beings may communicate in ways we can hardly fathom speaks to the imagination. We wish to understand. By trying so, throughout our human existence many methods of translation have been explored: from interpreting the intestines of rabbits, to making spectral analyses of chemical substances, or using artificial intelligence to decypher whale songs. Who are these ‘others’ we, humans, coexist with?

Image above: text set in Ips typography, a font based on spruce bark beetle traces left in tree bark.

Water bodies

For centuries, the inland waters of the Netherlands have been constrained by dikes, sluices, dams, pumps, mills and pipes. Calmly guided through canals, Dutch waters rarely run wild and are barely audible, except through the mediation of machinery such as motor-driven ship propellers or mechanical floodgates.

During a Hydromedia residency research visit to the HDSR wastewater treatment plant in Utrecht, I noticed two things. The site, which processes 65 million litres of water a day, was eerily absent of water; it is hidden in pipes and tubes, only to surface in huge reservoirs towering above the ground. The grounds were surprisingly quiet, apart from a soothing, constant, mechanical hum.

At the top of the metal staircase leading to the surface of one of the basins, however, we passed a tall metal pipe, pointing skywards and covered in grating, which emitted loud noises as if something inside was growling and grunting, roaring like a wild animal trapped in a cage. A few metres below, water was sloshing about violently, its sound amplified by the metal pipe; the opening at the top became its mouthpiece.

I was struck by the strange unevenness of the noise, reminiscent of the syntax of human speech: here, released from the reservoir and gasping for air, it seemed as if the water was trying to speak.

It turned out that these episodic speeches are triggered when the reservoir overflows and dumps its excess water into the pipe, processing up to 3.5 million litres per hour: almost a thousand litres per second. By comparison, an average bathtub holds about 130 litres. The sheer force of the water flowing through the pipe caused the metal platform at the top of the installation to shake, a behaviour very different from the usual, controlled flow of the rivers, streams and ditches that cut through the Dutch landscapes.

The water trapped in this pipe seemed to be liberated: free to find a voice loud enough to be heard. Who is speaking? Is it here where the lost ancient spirits of the Low Countries are hiding?

In search of a potential water spirit, I recorded the sound and then isolated the water’s speech by visualising it in animation. Using audio-reactive processes, the sound is expanded into a spatial visual language that still embodies the elusive, water-like qualities, while remembering the tube from which it came.

Nereda 2: a Hydromancy presents the process and the result of digital distillation, using a cascade of filters – including AI – to identify the voice from the deep.

Translations

The process perhaps requires a heightened awareness of ephemeral, non-human bodies, and in this case a particular sensitivity to the sound they can produce. I was taking pointers from an earlier project in which I translated European spruce bark beetle patterns left in the bark of infected trees into sound, using digital ‘image sonification’. In Nereda 2, the reverse was done: the audio became the image.

The aim of this adaptation is to transform a non-human entity into a form that people can grasp a little better: a hybrid of its original appearance and human mediation – in this case through the use of computer technology. For Nereda 2, the sound I encountered at the sewage treatment plant was first recorded with a mobile phone. Later, more professional recordings were made. For the final work, both types of recording were used.

The audio files were then transported into a computer: a digital environment that mimics the flux of water. The process was aimed at finding the hidden: the perceived speech, the ‘voice’ that seemed to speak, the form it might take. Nereda 2′ is a tribute to a presumed gasping water spirit that lives intermittently in the pipe of the eponymous sewage treatment plant’s reservoir. As a hypothetical, imaginary, mythological being, it can take any form.

Nereda 2: a Hydromancy was made as part of the Hydromedia project: “Hydromedia mobilizes the arts to visualize the Green Deal (area 7) agenda in tangible ways so to promote transnational dissemination and audience engagement.”

Hydromancy is a method of divination through water. The divinators are not the authors of the utterings.

The Diviners are not the Authors of the Utterings is inspired by the article ‘Why Diviniation? Evolved Psychology and Strategic Interaction in the Production of Truth’ by Pascal Boyer (2020, published in Current Anthropology, volume 61, issue 1)

The video uses an audio recording of the discharge of one of the bassins (“Nereda 2”) on the terrain of the HDSR waste water treatment plant in Overvecht (NL), which was then digitally distilled to reveal a speech.

“Psellus de damonibus sheweth how it is done: that the deuills creepe in the bottome, and send forth a still confused sound, which cannot bee fully vnderstood, that they may be held to say what euer come to passe, and not to lye.”

16th century, Juan Luis Vives as commentary on St. Augustinus “Concerning the Hydromancy Through Which Numa Was Befooled by Certain Images of Demons Seen in the Water.”

Screenings & exhibitions

AG, Utrecht (NL, 2024), SecondRoom, Antwerp (BE, 2024), Technische Sammlungen, Dresden (DE, 2024-2025), Conjuring Creativity Conference #3, London (UK, 2025).