January 2019 Monitoring

Posted by: upperwalnutcreekaustin | January 20, 2019

January 2019 Monitoring

January 20 – although at 46 degrees it was a bit on the chilly side, it was beautiful today. Barely a cloud in the sky, guess the wind gusts from yesterday (up to 40 MPH) blew all the clouds away.

The stream and culvert both had a strong flow. About 9 days ago we had around .5″ of rain, and that was after nearly 2.5″ earlier in the month. So it’s no surprise the stream has a noticeable current. And it’s wide enough to flow over the entire width of the waterfall, for the first time that we’ve seen in months.

The main part of the stream under the bridge has been closer to the south side for some time now, so the 4 bridge columns were mostly out of the water. The water on the upstream side of the bridge was high enough that it covered the rest of the stream bed, and the trail crossing rocks were completely gone. Crossing the trail would require wet feet. And the gravel bar is only a small part of its former self.

I saw a few gambusia (minnows) just upstream of the sample site; we didn’t see any other aquatic or land animals. No birds, including pigeons. The “sometime island” rocks upstream from the waterfall were not visible, and there was a bit of water in the inlet where I stood to observe the “sometime island” rocks (couldn’t get any closer with dry feet). I did notice some loose gravel near the inlet, as though the stream had been much higher and dropped the gravel as it receded.

There was no surface algae; upstream of the waterfall there were numerous long underwater strands.

As expected given the cold water (9 C, 48 F) the dissolved oxygen was very high – 11.6. That’s the first time we’ve seen it over 10 in over a year. And the water was incredibly clear.

Observations:

Air temp
Water temp
Dissolved Oxygen
pH 7.0
Nitrates 0.3
Dissolved solids/transparency
Conductance 580