October 2010 monitoring

Posted by: upperwalnutcreekaustin | November 10, 2010

October 2010 monitoring

Today (Oct 17) was a beautiful day to monitor – a few clouds in the sky, and very pleasant temperature for a change.

No rain for several weeks, so the water level is definitely low. Although no surface algae at the actual sample site, around the waterfall upstream there is extensive algae where the water level is only an inch or 2 deep. Much of the stream is completely covered with green, as shown below. Yuk. Even so, we did see some minnows, both just downstream of the bridge and upstream of the waterfall. The sample site has a sheen as though there’s something on the waters. And downstream from the sample site the sheen was much stronger and there was some “tree debris” floating in it.

One thing that was curious given no rain for several weeks is the flow from the storm drain – much more water than I would have expected, as shown below. That’s a good clue (per LCRA) that there may be a broken pipe feeding into the storm drain, which may also be the source of the e-coli contamination, which the City is investigating. The e-coli was highest (avg about 2800) just above the sample pool and about half that at the storm drain, probably because of the strength of the flow.

There are still some signs of the recent flood – trees bent over, and the rocks that people often used to cross the stream without getting wet feet are gone. Probably carried downstream during that flood.