Dye tracing equipement : Le fluorim?tre STREAM

Leclused

Active member
Hi,

The following event https://www.facebook.com/events/574504537202507/?ref=newsfeed will show a new tool for dye tracing.

This measuring tool has been designed by a caver in the first place and was then taken over by scientists for perfection and further development.

We (SC Avalon) had the change to work with this tool for several projects the last few years (we were priviliged :) )

The following report give you some insights about one of the projects (in dutch) were we used several  fluo-G tools. Fluo-G is the name that the initial designer gave to the tool. It was later changed to STREAM.

https://scavalon.blogspot.com/2021/06/hydrologisch-speurwerk-in-de-vallei-van.html




 

TRAQUA

New member
Later this year, around September-October we will also organise a webinar series with hydrogeology expert presenters specifically about dye tracing in different settings (both natural and artificial environments). One of the series will focus on tracer tests in natural environments. This might be interesting for this group as well. More info will be published later on our LinkedIn page: https://www.linkedin.com/company/traqua or on our Twitter page: https://twitter.com/traqua_be
 
Amaël will be present at both Eurokarst in Malaga (http://www.eurokarst.org/) with an info-stand + presentation and the UIS conference in France (https://council.science/events/18th-congress-speleology/), also with a presentation.
The photos in the links above show bright green rivers and ditches - that was a quite a dose of fluorescein. Turning a whole river bright green must be great fun, but it's a bit unsubtle.

Does anyone have experience of using fluorescein in a caving context at very low concentrations below what can be seen with the naked eye, or the use of colourless Optical Brighteners? Plus, of course, the opto-detector design and data loggers to record the flow results dynamically, ideally at next to no cost for use on an amateur basis.

Perhaps 20 years ago I looked into this, using exclusively OBs, and I built my own optical sensor for material like Tinopal that was coupled to a data logger, with encouraging results at proof-of-concept level. I asked BCRA to fund chemical supplies for further R&D, which they refused. So the project got shelved, but I still have all the bits.
 

TRAQUA

New member
The photos in the links above show bright green rivers and ditches - that was a quite a dose of fluorescein. Turning a whole river bright green must be great fun, but it's a bit unsubtle.

Does anyone have experience of using fluorescein in a caving context at very low concentrations below what can be seen with the naked eye, or the use of colourless Optical Brighteners? Plus, of course, the opto-detector design and data loggers to record the flow results dynamically, ideally at next to no cost for use on an amateur basis.

Perhaps 20 years ago I looked into this, using exclusively OBs, and I built my own optical sensor for material like Tinopal that was coupled to a data logger, with encouraging results at proof-of-concept level. I asked BCRA to fund chemical supplies for further R&D, which they refused. So the project got shelved, but I still have all the bits.
Hi Stuart,

If you see pictures with bright green rivers it's either for the picture, it just stands out more 😅, or it was at the injection point where a large surface or groundwater network had to be covered (or in sewers, where more dye tracer needs to be added to be visible over the turbidity and artificial brighteners in laundry products).

The fluorescence usually subdues after a few 100m and becomes invisible to the naked eye. Our fluorometer optical probes have very low detection limites (0.06-0.09ppb, which is way below the detection limit of the naked eye) which allows the use of very small concentrations of fluorescein (it will still be visible the first few meters after the injection point but becomes invisible when diluted). It is also possible to use colourless fluorescent dyes (sulforhodamine B) or UV tracers (amino G), but they are more expensive and a higher concentration is needed as the fluorometers are a little bit less sensitive to these kind of tracers.

It is perfectly possible to use fluorescein in low concentrations in a caving context when using fluorometer probes. My colleague Amaël Poulain, who is a hydrogeologist and a caver actually did his PhD on Belgian karst systems and did a lot of dye tracing tests in caves. Do not hesitate to contact him if you wish more details (ap@traqua.be) about his experiences.

We also have a lot of experience in opto-detector design since we developed and produced our own fluorometer (https://traqua.be/en/technologie/). Unfortunately I can't give you all the technical details. We do realise that caving associations don't have the budget for large scale dye tracing experiments, which is why we opened a project call specifically for speleology clubs (https://www.linkedin.com/feed/update/urn:li:activity:6917037637899845633).

Cheers,
Sofie
 

andrewmcleod

Well-known member
There are people in BCRA with a lot of experience in dye tracing and, in some cases, a lot of the relevant fancy kit (and the academic background to match). The BCRA has run dye-tracing workshops before and, *if anyone was super keen to actually run and organize it* (which I believe has always been the issue in the past), I'm sure they would support setting up a hydrology special interest group.

There is a tendency in UK caving for people to reinvent the wheel...
 
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