Eyes on the Eel: Level 1

Level 1.  Casual assessments

2-6 cross-stream transects (perpendicular to flow).

Choose a study location that you can locate on air photos or our LiDar generated maps, so we can mark and relocate positions of the transects. Set up a data collection sheet in a Rite in the Rain book as shown below. Choose your transect location, and take upstream and downstream photos, as well as a photo showing the river reach to be covered. At a given river location, start at the water’s edge (noting whether edge is river right (RHS) or left (LHS) looking downstream). For these assessments, the x-stream interval is estimated by pacing, using a meter-tape strung across the channel is more accurate (see Quantitative Transect method below). Depending on stream width, take X-stream site readings every 1 m or 0.5 m (try for at least 10 sites per transect). X-stream 0 would be from the wetted edge to ~1.0 m across the transect. X-stream 1 would be ~1.0-2.0 m across the transect. For each site, measure the depth at the near edge in cm. At each x-stream site, estimate the most common (dominant), 2nd most common (sub-dominant) size, using coarse Wentworth categories listed below. Surface flow can estimated in the broad but ecologically meaningful intervals listed below—use a floating object or bubble). Algae is described as attached or floating or loose but deposited. Describe dominant and subdominant taxa, if unknown, take a photo or a smidge and put it in a numbered whirlpak or vial, and id it in lab). Then estimate the height estimated (in cm), the density (% of substrate covered by algae, see scale below) and if possible, describe the condition (fresh to nearly detritus, see methods table. Note cased caddisflies if you see them, and any other conspicuous fauna (e.g. vertebrates, native and exotic, perhaps with estimates of their lengths). Then make any other critical notes that are quick. One transect should take only 5-10 minutes. Two transects are informative, of course more are better. It’s convenient to alternate the zero transect, starting on RHS or LHS. I tend to space transects ~5 m longitudinally on channels that are 30 m wide or less, but choose the longitudinal spacing that best describes the condition you want to document at the location.

Gear needed

  • Rite-in-the-Rain waterproof or water resistant notebook or this type of paper on a clip board.
  • A waterproof digital camera
  • A wading rod marked in 10-cm increments (Mary Power uses a ski pole, great for preventing falls and pushing aside poison oak, as well). Meter sticks are pretty flimsy for wading and in fast currents.
  • A 15 cm (6 inch) plastic ruler if you’re learning how to visually estimate rock particle sizes in the Wentworth series.

Return to main Eyes on the Eel page