Rumble in the Rainforest
The battle for supremacy continues in Goldstream Provincial Park on May 28, 2018. In this corner: Image Velocimetry; in this corner: Tracer methods; in this corner: hydroacoustics; and in this corner: SWAG[note]Scientific Wild Ass Guess can be as accurate as other measurement methods, but rarely has as low an uncertainty, unless you are Stu Hamilton.[/note] Come out and represent your tribe and be rewarded with immortality.[note]We intend to write up the results as creative non-fiction, as we did for the Lethbridge Flow Regatta in 2017 and the Vienna Flow Regatta earlier this year.[/note] Please note that there will be beverages and a hot lunch for every participant, Winners and Losers! You may even learn something, guaranteed![note]Actual retention of learning not guaranteed[/note] Be sure to register here.[note]Registration fee covers bus transportation to and from the site.[/note]
Peyto Glacier AutoSalt Install
We recently had the honor and pleasure to return to Peyto Glacier in Banff National Park near Canmore Alberta. Our host, Eric Courtin from the University of Saskatchewan’s Centre for Hydrology, arranged a helicopter flight to site, gourmet meals, and even ice-cold beer[note]After some bartering for a kitchen scale[/note] This year, the skies were crystal clear compared with the haze from last year’s forest fires. The glacier again struck its best pose for the temporal travelers who traversed it’s tongue, shown in Figure 1.
We began each day with a hike from the luxury accommodation of “The Lodge”, shown in Figure 2, complete with faded photos from the 70s, cribbage, candles in whisky bottles, and a coupla last will and testaments. Pretty standard stuff.
We installed a 200 litre AutoSalt tank at the outcropping of a subglacial pool, shown in Figure 3. This system was flown by helicopter to site. A Neon NRT satellite telemetry system was installed nearby, courtesy of Steve Biduk at GeoScientific Ltd. This allows us to monitor the channel water level, the AutoSalt reservoir brine level, and the injection amount, as well as request a manual injection. The brine is injected into a well mixed constriction in the channel. The Injection and T-HRECS measurement sites are in these Google Earth files.
The conductivity is measured about 500m downstream of a braided riffle, where the flow again is constricted as it enters into a narrow canyon. Normally we try to avoid braided channels, but this was the only site available. Figure 5 shows the canyon and the Right Bank (RB) probe site. The LB probe pipe was mounted on the bedrock outcropping on the left bank and the cable run up the till slope, anchored by steel rod driven into the slope, with the datalogger high above the flood level and again anchored by steel rod. Not the ideal site, but ideal is generally the exception. Several holes are drilled into the bottom of the pipe to allow in flowing water. With the probes at these sites, we measured flows comparable to a concurrent ADV measurement.
Because of the long mixing length and transit time of ~45 mins (at this flow), we opted for a longer sampling frequency of 20 seconds, rather than the usual 5 seconds. This should result in ~4x longer battery life with no degradation of data quality. The T-HRECS dataloggers record EC and Temperature to an internal SD card which can log 5 second data for years. The 4 replaceable D-Cell batteries are expected to last ~3 months at 5 second log interval. The Probe is designed to be easily installed, with the datalogger high above flood levels and no solar panel installation required. Often a simple 10′ x 2″ aluminum pipe with a bolt at the bottom, ~8 samples holes, and the Datalogger clipped to its top will suffice.
We calibrated the pump system, calibrated the EC-T probes against reference probes (CF.T calibration), then began validation measurements between the AutoSalt system, the QiQuac system, and concurrent ADV. Several measurements taken upstream of the T-HRECS conductivity site with the QiQuac on the LB at the outlet of a small pool with a backeddy. This was a poor probe location, and may have been influenced by upstream inflows. Once these anomalous measurements were removed, all measurements were within each other’s uncertainty estimates.
That was the end of Day 1. We were all burnt to a crisp from the sun and snow and scrambled back to the Lodge for some BBQ and beverages, as shown in Figure 6.
Day 2 had us finish the LB probe installation, wire the AutoSalt to the NRT, and perform several more measurements. We let the system run overnight, and my furry friends ensured I got an early start on Day 3. I performed another download of all systems and noticed the LB T-HRECS was not at the bottom of the pipe. I moved it down, ensured I’d turned on both LB and RB T-HRECS, took a photo, and backed away slowly, our Peyto Glacier Q traps loaded. We then began the exhilarating and exhausting 2-hour hike back to civilization. We can now watch the measurements occur from the comfort of our favourite coffee shop.
It’s that easy! Usually installations can be completed in less than a day, but depending on the logistics and access, you may want to plan on a 3 day trip to ensure everything is working properly. Contact us to order your AutoSalt system today!
