August 2018

August 15 – during the morning monitored it wasn’t overly hot – around 90 – but the humidity made it seem hotter. This became day 29 of 100+ degrees and no end in sight. Yuk.

We had a brief break from the heat last weekend and enjoyed the half inch or so of rain, but that is now a distant memory for us and for the stream. My first reaction when seeing the stream was “ugh”. As usual for this time of year, it’s low with a very sluggish current. Unlike last time there was a fair amount of scum near and beyond the sample site.  This is the most scum we’ve seen in a while. Also, further upstream above the waterfall and dry inlet, I saw shiny patches on the water. Not sure what caused them, but the schools of tiny gambusia (minnows) didn’t seem affected. We also saw a turtle by the sample site.

The storm culvert still had a reasonably good flow, though the water flowing from the street level was still caught in a couple of pooled areas that had scummy surfaces. The stream is low enough that the upstream bridge column’s “foot” is completely dry, and one of the interior columns is nearly dry as well. And due to the low stream I could have crossed to the south side with dry feet both at the trail crossing downstream of the bridge or even at the upstream side. The waterfall still flows over a small section, and upstream of that I could have walked up to the dry “sometime island” rocks if desired. We need rain!

The gravel bar that graced the middle of the stream just above the trail crossing for years is completely gone. Now the stream lazily flows through and around the stones at the trail crossing. There was no surface algae and not much submerged algae. The dissolved oxygen was only 2.1, the lowest we’ve seen it in a long time. And e-coli is . The 3 ML samples averaged about 166 colonies. Not bad for an urban stream.

Observations

Air temp 21 C
Water temp 26 C
Dissolved Oxygen 2.1
Specific Conductance 460
pH 7.0
Transparency 1 meter

sample site from north bank

sample site and beyond

scum by sample site

scummy surface by trail crossing

scummy stream near trail crossing

trail crossing closeup

stream and under bridge from north bank

low stream under bridge

stream from above culvert

dry streambed upstream side of bridge

stream above culvert inflow

low stream below waterfall

waterfall are and upstream

very low waterfall

dry inlet above waterfall

dry sometime island rocks

low stream above inlet

downstream view from above inlet

dissolved oxygen 2.1