Pre-Trip Field Day Test

Before heading off into the field, I decided to trial a few aspects of my methodology in order to identify weak points, work out any kinks, and have time to revise techniques before flying to Wyoming. I planned an overnight field trip with Madelyn (research assistant extraordinaire) at McKinney Falls State Park and decided that we’d gather mock data, just as we would in our actual field setting.

Although we wouldn’t be able to practice every technique (there’s no snow or ice), we’d be able to accomplish quite a bit. A few trial items:

  • Backpack weight
  • Field note recording
  • Hiking pace
  • Food/water supply
  • PLB accuracy
  • Phone GPS accuracy
  • Quadrats/Transects (sampling, identification)
  • Water sample gathering
  • River width, depth, cross sectional area, velocity, profiling
  • River depth sounding and profiling
  • Pack rafting
  • pH testing probe and strips
  • Conductivity testing

We headed out on Thursday afternoon and made it to McKinney Falls right when the sun was at its most brutal. Other than the heat, it was a really nice day and the park wasn’t too crowded.

Field site for river width, depth, velocity, discharge, pH, temperature, and conductivity.

We chose a spot on the river to test methodologies for basic data like river width, depth, velocity, and discharge. I wanted to verify our handheld sounder measurements against manual depth measurements, but realized in the field that the unit didn’t come pre-loaded with a 9-volt battery. I had AAs and AAAs in my pack, but no 9Vs. Duh.

Our second mission was to test the handheld pH unit against litmus pH strips. One thing about pH meters is that they require calibration. I wanted to know is whether the unit would offer accurate readings after being calibrated two days prior. (I don’t want to bring extra supplies to calibrate on the long hike if I don’t need to.) So, I used the handheld unit to take pH readings and then Madelyn and I used litmus strips to test pH. The handheld unit returned a value of 8.1, whereas the litmus strips showed a pH of 6-7. This likely means that the handheld unit needs to be calibrated in the field before every use. That’s a bummer, but it’s manageable.

Quadrat in action

The next step was to compare the readings of two electrical conductivity (EC) units, which both use total dissolved solids (TDS) as a proxy for conductivity. I learned that conductivity readings change over very short distances in the water. (We noted a need to look up proper methods for obtaining measurements. Maybe from sample jars and average the values?) I also learned that walking through the water throws off the readings because the sensor picks up on the kicked up sediment. That means we’ll have to find a place to take conductivity measurements where we don’t have to get in the water.

The walk back helped us gain perspective on the weights of our packs. I had an ultralight mentality when buying supplies, so it mostly worked out great. I did find that the weight distribution straps on my bag need adjustment before the big trip – no big deal. Madelyn is also considering investing in a pair of lightweight water shoes for the trip to prevent over topping in her hiking boots. (I wore my Keen Newports to McKinney Falls, which was better than switching shoes mid-route – however, they’re super heavy for long-distance hiking.)

In the evening, Madelyn and I found a suitable location to test quadrat data collection on the west end of the Onion Creek Trail. Madelyn worked out a great system for taking notes on quadrat sections with gridded paper, which made taking notes a cinch. It took about 15 minutes to collect data. As a last note, I was thrilled that we reached 90%+ reliability on gathering quadrat data. We’ll have to reestablish in Wyoming.

Sitting by the quadrat off Onion Creek Trail.

On the second day of our field testing, we walked to Upper Falls to test transect sampling, water sample collection, and the handheld depth sounder (I picked up batteries). We found a slow-flowing shaded area on the river (leading image) and started by laying out our tape reel so that we could take depth measurements at pre-determined intervals. However, when I tried to take measurements, the unit malfunctioned. At first, it wasn’t offering a reading at all. Then it returned a reading of 338ft, which was a far cry from the true 1.5ft depth. On the other hand, it displayed accurate water temperature readings of 85.7°F, which was great. I called Hawkeye directly and they offered to connect me with a tech representative through email to resolve the hardware problem. It’s been more than 24 hours and I still haven’t heard from them, so I imagine it’s going to take a little nudge to get them to work it out.

Madelyn taking field notes on water samples.

We collected four test water samples and walked through the process of field-rinsing the bottles in source water and capping them underwater. Since the GPS wasn’t at a high enough resolution to pinpoint the water collection sites (it looked like they were all coming from the bank area), we took notes on the source for each sample and named them accordingly. I also took pictures of the collection site so that we could label it for record.

Water sample collection sites labeled 1-4.

Then, we moved on to transect testing. We used tent stakes and 500-pound paracord to make the transect. Then, we used the open reel tape measure to mark intervals on the the transect line. A few notes on this:

  1. Instead of using the open reel tape (converting between imperial and metric), we’ll pre-mark the transect with meter lines for fieldwork.
  2. We’ll need to bring a mallet into the field to hammer down the stakes.
  3. There are two ways to sample along a transect that both seem to accomplish our objective, but one offers more data. I’m going to revise our methodology to make sure we gather more data the next time around.
  4. We practiced with a 10m transect, but we’ll be doing 50m in the field. Either way, we reached 95%+ reliability on the Texas plants we identified. We’ll need to reestablish in Wyoming.
  5. Finally, I need to get odor-proof sampling bags and gloves to handle clipped samples. I didn’t think to bring gloves this time around.

From there, we headed back to the other side of camp via the Onion Creek Trail. I wanted to gather as many GPS points as possible to test the accuracy of the personal locator beacon (PLB) against my phone GPS. A few things I learned:

  1. I set the PLB to ping every 5 minutes and it seemed to work while I was walking. When I was stationary, it shut down to save battery. That’s a great feature, but I noticed that it didn’t always click back on when I wanted it to. On several occasions, it didn’t click back on until I was already half a mile into a hike.
  2. The phone GPS works better for navigating on trails than the SpotGen app because it has a better idea of Google’s path-based map, but the SpotGen worked much better off-trail.
  3. SpotGen keeps your GPS points for 30 days, but it doesn’t let you download a large batch of points to use later. In this case, I wanted a .csv file of every lat/long pair for the duration of the trip. Online, they displayed page-by-page and I would have to download them manually. Instead, I called SpotGen and they sent me a .csv file with every GPS point. No big deal, but not the most convenient thing in the world.

As a final note, I realized that we brought way too much food and not nearly enough water for our trip. We went through about 3-4 liters a day per person, and that’s not at all manageable on a backpacking trip. It won’t be as hot in Wyoming, so that should help us reduce our water load. On the other hand, we have life straws to make sure of the proximate water supplies in the field. However, it’s probably still a good idea to plan on packing as much water as we can tolerate carrying, especially since we’re using some water for cooking.

Nighttime meal of freeze-dried jerk chicken and rice. Boil some water, pour it into the bag, and wait 20 minutes. It wasn’t too bad.









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