June 2016 monitoring

Posted by: upperwalnutcreekaustin | June 4, 2016

June 2016 monitoring

This will be a 2 part post.

June 4 – part 1 – was after a very soggy week. A year after the Memorial day/week flood of 2015, it looks like a repeat of that time. I stopped by the site to see the effect of around 5″ of rain this week. So far the annual rain totals for Camp Mabry is 7″ over normal and Bergstrom is 15″ over normal. Lake Travis, considered full at 681, is over 690 – may not sound like much but that’s 9+ ft extra for how many miles? It’s a big lake. And LCRA has opened some floodgates to prevent the homes etc. that were built below the top of the dam from flooding, but they don’t want to open too many because of all the extra water already downstream. The lake is continuing to rise, even without more rain… and more is forecast for tomorrow – radar shows a huge system of rain slowly rotating from Houston to the west of Austin. Just like earlier this week.

Yesterday it rained 1.5″, enough that with the rains earlier this week the normally dry headwaters of Walnut Creek turns into a swiftly flowing stream. And all that water, combined with other tributaries, turned the normally placid Walnut Creek at Metric into a fast stream that would be dangerous (deadly?) to cross on foot. And this is nearly 12 hours after the last rainfall. Can only wonder how high it was last night and last week. We’re supposed to get more rain tomorrow, then the sunshine returns. I’m almost ready to swap lower temperatures (high in low 80s, when the normal high is 90) for some sun!

June 8 monitoring

Summer is here – although the air temp registered at 84 F, it seemed much warmer, especially in the sun. The stream has returned to a near normal level, and there’s plenty of water gushing over the waterfall. The water from the culvert is also flowing at slightly above its normal rate. Above the waterfall, I couldn’t get close to the “Sometime Island” rocks in the middle of the stream further upstream, and those rocks were not visible. The inlet above the waterfall – the closest I could get upstream – was partly full. The stream was high enough so the trail crossing was partly submerged; anyone crossing it would get wet feet.

The floodwaters had clearly been high; there is some new debris on the hike and bike bridge, as some of the photos show. And it was moving enough to dump new sand under the bridge where we normally set up the monitoring – that area had been all rock. now there are several inches of sand. Impressive.

No surprise, there is no surface algae. And it’s been long enough that the dissolved solids have dispersed, the water is very clear. We saw numerous minnows but didn’t hear any birds – no idea where the pigeons went. We also saw about a dozen or so orange sandbags from the hike/bike trail construction on the downstream side of the bridge, by the gravel trail crossing area.

Observations:

pH 7.0
dissolved oxygen 7.3
Air temperature 29 C (84 F)
Water temperature 25 C (77 F)
Specific conductance 650