Friday, October 7, 2011

Photo: Water depth markers

The red stripes on the bridge are not just for decoration. As this photo shows, the red stripes are 2 feet (.6 m.) apart and markers to show the depth of the water when there is water flowing in Indian Bend Wash.

The red stripes are shiny tiles inlaid in the cement, which makes sense so they do not have to be painted. The design of this bridge seems to show that it is intended to regulate the amount of water downstream. The holes for the water to flow through are only about 8 feet (2.4 m) high, but the markers anticipate that water could be 14 (4.25 m) feet high. The bridge will cause water to back up and flood the McCormick Ranch Golf Course and will let only the amount of water that can fit through these tunnels to flow downstream.

It is hard to imagine that in the desert, where we get only 7 inches (17 cm.) of rain per year, we need flood control projects, but we do. Heavy thunderstorms in the summer can cause localized flash floods. This bridge looks very strong. I can remember about 30 years ago there was a flood that wiped out every bridge across the Salt River bed in Phoenix except one. The Salt River is usually dry, and until the water subsided the Valley was cut in two, with people having a very hard time to get from home to work if they worked on the other side of the river bed. The one bridge that survived was the oldest of the bridges.

This week we are showing photos of the subtle beauty of nature in Yosemite National Park on our Viva la Voyage travel photo site.

4 comments:

Dave-CostaRicaDailyPhoto.com said...

From a distance one would have thought that the red stripes were just for decoration.

Sharon said...

Hey Julie, I remember that flood very well. I was one of those people living on one side of the river and working on the other. The day that happened, it took me 10 hours to get home. I didn't go to work the next day because of a huge headache the doctor said was from breathing too much carbon dioxide. After that, my employer had me switch places with another employee who had the same problem, opposite side of the river. So, for about 3 weeks, I worked from a branch location and the other woman worked at my desk at the head office.

Teresa said...

This is really interesting....great way to track the rainfall!

I would have thought from the distance it was purely decoration, too.

J Bar said...

Fascinating.
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