June 2019

Posted by: upperwalnutcreekaustin | June 20, 2019

June 2019

June 19 – it’s (finally) starting to be a typical Texas summer. For the last few weeks it’s been rainy, cloudy and relatively cool – the humidity wasn’t too bad given the highs in the 80s. But now it’s summertime, with highs in the upper 90s/100 and humidity not far behind. Yuk.

Since our last monitoring session it has rained nearly 3″. Thanks to all the rain, both the stream and the waterfall are flowing well. And sadly, there’s a fair amount of additional trash in the culvert – at least it gives an idea of how much rain we had at a time. Likewise, we saw a bit of new trash on one of the exposed rocks just upstream of the bridge. We also saw a school of gambusia (minnows) above the waterfall and a few close to the sample site. Also thanks to the rain, there’s no surface algae and only small clumps of submerged algae. And above the waterfall and inlet, the “sometime island” rocks in the middle of the stream appear submerged. I couldn’t get close enough without wet feet to see them.

The trail crossing area is completely wet, there’s no rocks there so crossing the stream requires wet feet. Even the upstream side has too much water to cross with dry feet. And the gravel bar that has existed on the downstream side for many months is nearly gone, it’s just a shadow of its former self.

Still no pigeons or other birds at the site (pigeon droppings are a possible e-coli source). E-coli continues to be at an acceptable level for an urban stream. With 3 ML samples, the control and sample sites both averaged just below 100 colonies.

Observations:

air temp: 27.5 C
water temp 25 C
dissolved oxygen 6.7
pH 7.0
specific conductance 370
nitrates < 0.3
transparency (dissolved solids): 1.2 meters