March 2011 Monitoring

Posted by: upperwalnutcreekaustin | March 29, 2011

March 2011 Monitoring

March 27 – After being unseasonably warm for a couple of weeks (including during SXSW) – in the mid 80s instead of low to mid 70s – it’s finally cool again. It was 56 earlier this morning, absolutely gorgeous, despite the full cloud cover.

No significant rain in over a month and we’re officially in a drought, so unless La Nina changes and we get a few inches of rain in the new couple of months, we’re heading for another dry summer of many triple digit days. Not looking forward to it.

The site is definitely showing the effects of no rain. The water flow is very low – the waterfall is barely there – and the algae is covering nearly all of the surface that isn’t under the bridge (in shadow). It’s even covering the area at and just above the sample pool, which made getting the water samples a bit of a challenge. There’s also some scum on the surface, much more than normal. This is not the type of green we like to see.

We saw a small turtle at the sample pool but didn’t notice any fish, though the extensive algae cover made that tricky. And the storm drain culvert just upstream of the bridge continues to have a steady water flow. We noticed that about 10 meters above the sidewalk and culvert that water also had a grayish tinge and scummy surface.

Readings/observations:
– air temp 14.5 C (58 F)
– water temp 16.5 C (61.7 F)
– Dissolved Oxygen – getting lower, 4.1
– pH 7.5 (usual)
– Nitrates were 1, which is not usual
– transparency was .82 meters
– Specific Conductance: 650

E-coli was “normal” for this site, about 950 for a 1 ml sample. Higher than it should be but much lower than the highest readings.

Regarding the hike and bike trail, we noticed a new sidewalk along Cedar Bend near MoPac while driving to the site but didn’t see any more changes at the actual site.