February 2018

February 16, 2018 – initially the sun peeked through the many clouds, though it finally lost the battle. The wacky weather continues – in the last week the temperatures have dipped to freezing, and today it’s supposed to be at or near 70. Very little rain, mostly fog and drizzle. While monitoring, it was in the 60’s.

As we walked down the slope to the stream, we noticed that much of the underbrush had been cleared since our January visit. The culvert that flows from the parking lot to the stream had also received attention: the little “dam” which caused water to mostly trickle through after filtering through dirt and leaf debris had been cleaned up somewhat. As a result, the flow was somewhat stronger.

The algae was very extensive, more than we’ve ever seen. Upstream of the sample site the algae nearly covered the surface and submerged algae did cover the streambed to the point that I could barely see any of the underlying rock. Quite a change from our January 20 visit. There was even submerged algae under the bridge, the first time I’ve ever seen it there, in the permanent shade. The extensive surface algae extended as far upstream as we could see, so we’re wondering if there was some pollution – our tests didn’t show anything unusual, but they just test for pH, nitrates and e-coli.

The stream was high enough (normal flow) that the feet of the 4 bridge columns were in the water, though the waterfall only had a small flow over the far end  -and lots of algae – and a bit further upstream the inlet was dry. And just upstream of the sample site at the trail crossing area, there was only a fairly narrow section on one side of the gravel bar where the water was flowing downstream. On the south bank side of the gravel bar rocks were covered with algae and the water was low enough that there was no flow.

The stream’s surface at the sample site was a bit scummy (see the photo), and I could see some underwater algae there, even though it’s at least a meter deep.

Didn’t see or hear any pigeons (their droppings are a possible e-coli source from roosting under the bridge) or other birds. E-coli was higher at the sample site than at the control site by the waterfall, but not overly so. For 3 ML samples, the average site colony count (based on 2 samples from both sites) was 316 (sample site) and 200 (control).

Observations:
Air temp: 19.5 C
Water temp: 16.5 C
Dissolved Oxygen: 7.5
Specific Conductance: 510
pH: 7.0
Nitrate: 0.3
Transparency: > 1.2 Meters

 

sample site from north bank

closeup of sample site from north bank

sample site scummy surface

algae at sample site

streamside view of sample site and beyond

gravel bar by trail crossing

closeup of flow by gravel bar

gravel bar by bridge

stream from north bank

4 bridge columns in water

algae under bridge

stream from above culvert to under bridge

extensive algae upstream side of bridge

culvert inflowing area

inflowing culvert debris cleared

view of stream from above culvert

stream and algae upstream side of bridge

stream from waterfall to bridge

stream area by waterfall

waterfall with algae

stream above inlet

closeup of waterfall with algae

stream near sometime island rocks

closeup of algae just above waterfall

stream and inlet above waterfall

closeup of algae above inlet

downstream view from above inlet

dissolved oxygen 7.4