A New Way To Study Estill Fork

We spent most of the day yesterday at Estill Fork characterizing a 60 meter strip of riffle as darter habitat. The exact site we worked is mostly downstream from where we've usually gone to collect shiners. The water level was the lowest I've seen there. If you look at the photo below, you don't see much of the stream, which pretty much tells the story. What we did was to mark off every 4 meters on a 60 meter stretch (16 stations) and make depth and current flow measuresments at every quarter meter in a transect at each station. We used the default depth setting for measuring flow, at about 5 cm. Most of our measurements (and there were lots of them!) showed no or very little flow. This is kind of what I expected, since there are benthic boundary layers just above the sediment where frictional drag between the water and sediments slows down the current. This is where most darters spend most of their time so it's directly interesting to us.

Most of our time was taken up doing these current measurements, each for a minute, which adds up fast. The latter part of our visit we were rained on and threatened with thunder storms that never directly hit us, running just to our south. We did a "darter dance" seine haul at each station to census darters, characterizing them to species and sex, or just juvenile status if they're YOY. Our richest seines came up from the deepest water pockets near a tree's roots, where we measured no flow. In particular we found some beautiful, big greenside darters that surprised the students who had never seen big greensides before. The stations that were characterized by shallow, fast-flowing water contained tennessee snubnoses, rainbows, fantails and stripetails; the latter three were much less likely to be found in the deep pools, and tennessees were everywhere. Finally, we characterized sediment composition to percentage boulder, cobble, sand, etc. All in all a fun day.