December 2016 monitoring

December 12 – a beautiful, cool late fall/early winter day. The sun was shining, it wasn’t windy and at 59 the temperature was just about perfect for late fall.

A small, slightly smelly surprise awaited us as we walked down the hill next to the creek that flows from the storm drain into the main stream. The opening where the storm drain water flowed under the sidewalk was completely blocked with sediment and other debris, so the storm water was flowing over the sidewalk and across the normally dry rock before reach Walnut Creek. There were a lot of flies around that water, along with a faint whiff of sewage. Yuk. We gingerly walked through it to reach the sample site and our usual setup spot under the bridge.

The stream flow was low to normal (the “new normal” seems lower than my memory of when we began monitoring in 2006); there was a decent amount of flow over the middle of the waterfall but only at the middle. The stream is still low – there were some dry rocks directly above the waterfall, and the “sometime island” rocks further upstream were still dry. I could have walked to them but did not. We had a couple of inches of rain earlier this month and the stream was clearly higher at one point, based on a white blanket that was caught in the brush overhanging the stream just above the waterfall. Another telltale sign of recent rain was the water under the bridge (along with trash, which appeared to be from several people). The bases of all 4 columns were in the water, though just barely. I was able to walk to the middle of the stream on the upstream side of the bridge with dry feet.

At the sample site we saw one big turtle and a baby turtle; didn’t see any fish or birds. There was very little surface algae – only at the entrance of the storm culvert. Upstream of the waterfall the submerged algae was mostly long strands.

E-coli was very low: with 3 ML samples, the sample site only had about 50 colonies and the upstream control, taken  just above the waterfall, had no colonies. The rain earlier this month may have washed them downstream, and the cooler weather also helped.

Observations:

Air temperature 15 C (59 F)
Water temperature 13 (55 F)
Specific conductance 530
Dissolved oxygen 7.65
Nitrates .5
Transparency (dissolved solids) > 1.2 meters – very clear

 

sample site from north bank

trail crossing to beyond sample site from streamside

trail crossing closeup

trail crossing to gravel bar

stream from trail crossing to under bridge from north bank

stream under bridge from north downstream side

all 4 columns in water

under bridge water from rains by new trash

blocked culvert and sidewalk from downstream side

blocked culvert and overflowing sidewalk

blocked culvert and wet sidewalk

blocked culvert and wet sidewalk

culvert and stream to under bridge

culvert from middle of stream

blocked culvert and stream overflowing

low stream upstream side of bridge

north bank under bridge from middle of stream

overflow from culvert near waterfall

waterfall area overflow from blocked culvert

upstream view from under bridge

waterfall and upstream area

stream above waterfall to sometime island

general waterfall area with wet rocks from blocked culvert

streambed above waterfall

sometime island area above waterfall

upsteram of waterfall

debris above waterfall

downstream view from above waterfall

dissolved oxygen 7.65