Test strips: the Northern Reaches

Immerse yourself in an ambient sound portrait by Rob St John, captured one sunny afternoon on the remote upper stretches of the Lancaster Canal

Hydrophone recording above lock

Words, artwork and soundscape: Rob St John

Posted on 03/07/2019

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Driving along the M6 motorway between Lancaster and Kendal, you will encounter two road signs in quick succession: ‘Welcome to Cumbria’ and ‘Lancaster Canal’. It’s at this point that the motorway slices through the course of the Lancaster Canal, isolating the largely-unnavigable and highly-biodiverse ‘Northern Reaches’ of this already remote waterway.

Stretching for fourteen miles from the marina at Tewitfield, near Carnforth in Lancashire, the Northern Reaches – originally constructed between 1797 and 1819 – was closed to navigation in the 1950s and ’60s after the construction of the M6. More than 50 years later, the Northern Reaches are unlike any other stretch of canal I have visited. Aquatic plants have flourished in the decades since its use as a working waterway, giving the impression of a fen or wetland in places, and there are numerous bird species in the reeds and hedgerows fringing the water’s edge.

Northern Reaches Lancaster Canal Sound Portrait

Eavesdropping on underwater worlds

I created this sound portrait and artwork on a walk between the Tewitfield Marina and the open fields near Burton-in-Kendal. Walking from mid-afternoon to dusk on a sunny early summer Sunday, I documented this three-mile route using a set of microphones, and 120mm and 35mm film cameras. Ambient soundscapes were recorded simultaneously with a stereo microphone and binaural microphones. Binaural microphones are clever: they look like cheap earbud headphones, and are worn in the ears, recording a 360º soundscape around your head. Listening back on headphones, they offer a real sense of space: swans flying by and splashing through the stereo field, West Coast mainline trains rushing past your ears.

Another special kind of microphone – the hydrophone – allows you to eavesdrop on underwater worlds. Hydrophones are shaped like round fishing weights, attached to long cords. They can be variously placed, dropped or chucked into the water column, and, when settled in the bed sediment, often reveal busy and industrious underwater soundscapes. As transport routes intersect and rumble above the surface, a whole host of underwater insects create sounds – variously rhythmic, melodic and droning.

These sounds are largely produced through the process of stridulation, where aquatic insects rub body parts together to create sound, much like grasshoppers or crickets do. Whilst many of the insect stridulations we hear can’t yet be identified, a few can. The lesser water beetle call, for instance, consists of a series of clicks followed by a hum like the unfurling of a coiled spring. Hydrophones give us a sonic window onto a world otherwise inaccessible to the human senses: patterns and processes of life going on below the surface.

Above and below

The sound portrait follows my walk from the busy Tewitfield Marina, where the noise of the motorway and generator engines is inescapable, up a series of disused locks, each with a mini-waterfall, and ferns and rowan saplings growing vertically through cracks in the brickwork. We cross over the motorway, and gradually lose the background rumble of the cars, opening out onto the fields in the evening light, with only passing trains and overhead planes punctuating the chatter of hedgerow birds and ebbing curlew calls.

The sound portrait dips above and below water: each hydrophone recording differing depending on the aquatic life present and the speed of the water itself. Rumbles and hisses of white noise, however produced – the motorway hum, wind in the trees, rushing water – characterise the Northern Reaches soundscape. Where the water is still, hydrophones pick up resonances of this ambient drone, as it resonates through the water column and its buzz of underwater life.

Abstract rhythms, patterns and textures

Test Strips, Northern Reaches

The artwork was created from a series of long exposure film photographs taken along the same stretch of canal. It abstracts colour palettes along the canal – reed beds, duckweed foamed with road wash, bridge brickwork in the evening sunlight – and lays them out like a biologist’s ‘test strips’ used to determine water quality. Together, the sound and visual works form a document of the rhythms, patterns and textures of the lower Northern Reaches of the Lancaster Canal in early summer.

Field notes on hydrophone locations

0.00-0.30
Tewitfield Locks (disused). Water flowing gently; green algae and white foam road wash on surface.

0.46-1.18
Tewitfield Locks (disused). Still water immediately above lock overflow; water seems to pick up the hum of the motorway traffic.

1.30-2.12
Canal terminus at the M6; open channel.

2.30-3.20
Canal terminus above the M6; underneath metal maintenance structure; sounds like the metal is resonating above-surface noise into the underwater soundscape.

3.32-4.30
In reedbed in Northern Reaches above the M6.

Rob St John is an artist and writer based in Bowland, Lancashire. Focusing on the blurrings of nature and culture in contemporary landscapes, his work has been seen/heard at Tate Modern and the V+A, London, amongst many others, and in numerous artistic and academic publications.