A watershed 3 hydropedologic feature: Whatsit?

Last week, JP, Rebecca, Scott, Erik, Phoebe and I were digging soil pits for JP’s project in Watershed 3 at Hubbard Brook. About 10m upslope of these pits we began to dig the first pit for my project on the C horizon. Over the summer, I will be looking at the C horizon and characterizing the soil profiles and the geochemical and hydrologic properties. While digging the deep pit last week, we encountered an interesting discontinuity in the lower B horizon. As pictured, there was a dark streak running down through the lighter Bhs horizon. We were originally puzzled by the presence of this streak. Rebecca suggested that it was most likely a krotovina, an old animal burrow that had been filled in with overlying material. Or perhaps it was an old root tunnel? Regardless, it was interesting to see and got us excited to continue our projects for the summer.

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4 comments on “A watershed 3 hydropedologic feature: Whatsit?
  1. Maggie,

    That’s a very cool feature, which suggests some serious preferential flow into the dense C horizon. I am very excited about your REU project this summer. It will help us address the role of the C horizon in the development of hillslope lateral flow, water storage, and weathering. We have a pretty poor understanding of how these deep soils contribute to streamflow generation and solute export from headwater catchments in the northeast. Your work will be quite informative!

  2. Jeff says:

    A groundhog will rarely be so foolish as to dig it’s burrow in a swale, or to dig a plumb burrow rather than lateral and usually looks for an alternate exit. Exceptions abound, while evaluating a site I was caught by a summer thunder shower and noticed a burrow filling up. After the storm I pegged the water line with a twig, noting the time, and ran a calculation giving a perk rate of 20 minutes/inch. Never know when an opportunity to collect data might arise.

    Seeing your photo, not the soil, I’d consider another possibility, if this is a Blue Ridge or Appalachian soil you may be looking at rock controlled structure and a fault or float rock which intruded into the B and weathered in place. However, bedding coppralite or skeletons, or surface colluvium in the base would strike that idea, and endorse the krotovina.

    Best to JP in the mountains, from Jeff in the southern ridges.

    • JP Gannon says:

      Hey Jeff, great to hear from you! It’s really hard to tell from the picture but this thing definitely doesn’t come off as a decomposed rock in person. Like Maggie said it is full of material that is very similar to Bh horizons we see in profiles where we think there are concentrations of flow. It is potentially a kind of mini feature of some of the larger hillslope processes we are investigating.

      Additionally, as Maggie said, it widens up at the bottom at the till interface. Odd orientation for an animal, but maybe thats why it is full of soil and not creatures!

  3. Maggie says:

    Thanks Kevin- I am excited to see what comes of my summer research. Jeff- Thank you for your ideas! The pit was actually dug on more of a spur rather than a swale. While the streak seems quite vertical for an animal burrow, the narrow orientation actually leads to a spherical like deposit of Bh colored soil in the upper C horizon. The structure of the soil in the streak does not suggest that it is from rock but rather from soil material. I did not look for any coppralite or skeletons but the pit is still open and that could definitely be informative! I will have to examine it more closely on Wednesday when we head back out into the field and let you know what I find!