September 2016 Monitoring

September 17 – another hot, humid day. Typical late summer weather. The forecast high is mid 90s with humidity index of around 100. Ma Nature doesn’t seems to know or care that autumn is just around the corner. Sure wish she’d read the calendar!

No rain in weeks, the stream is easily as low as last month. The stream surface at the sample site and downstream is scummy, as is the surface of much of the inflowing storm culvert stream. In a couple of places where the culvert water pools it is so scummy it almost appears to be a solid surface – first time we’ve seen it that scummy. As I walked over the culvert to our usual setup site under the bridge, I caught a whiff of sewage. Yuk. Somehow with all of the scum the smell wasn’t surprising. Despite the scummy surface and no recent rain, the culvert had a good inflow.

The underwater algae above the waterfall and inlet has grown enough that it appears as a forest of algae. I didn’t see any schools of fish, possibly due to the thick algae growth.

We saw a small white heron standing on the gravel bank by the bridge; that was the only sign of birds. Still no pigeons. Three of the 4 bridge columns are in the water (barely). The waterfall is flowing and gurgling over a small area; the rest is covered with algae, as usual at this time of  year. The inlet above the waterfall is bone dry, and the “sometime island” stream bottom is also completely dry. The stream is low enough that I was able to walk up to and (had I so chosen) above the sometime island area. And I was also able to walk into the middle of the stream bed by the bridge – I could have crossed to the south side easily, had I wished to do so.

The transparency tube was completely clear. E-coli measurements were within acceptable limits (average 400 colonies for 3 ML samples for the sample site and 300 colonies upstream).

All in all, a typical September for this section of Walnut Creek.

Air temp 28.5 C
Water temp 26 C
pH 7.0
Dissolved Oxygen 3.6
Specific Conductance 610
Transparency (dissolved solids) > 1.2 meters

sample site and downstream

sample site and downstream scummy

sample site closeup scummy

sample site scummy

trail crossing closeup

heron below bridge

heron below bridge

Trail crossing area

downstream side from under bridge

downstream side of bridge from north bank

under bridge to crossing area from north bank

stream under bridge

stream under bridge

upstream from under bridge

Stream under bridge from culvert

stream and south bank above bridge from culvert

waterfall area

upsteram view from middle of streambed

scummy culvert stream

scummy culvert stream closeup

waterfall and beyond

dry inlet above waterfall

Algae above waterfall

downstream view from above inlet

dry sometime island above waterfall

algae underwater forest above inlet and waterfall

dissolved oxygen 3.5