Saturday, September 28, 2013

River magic...

As I posted earlier (Busted 6/13/10), several close calls on the Delta River at Black Rapids prompted Mike and I to find a better way to survey the river.
This year we finally got Richard (the doppler wizard) to bring down an acoustical doppler meter. These meters use a sonar-like application for depth and velocity, and GPS for position.
We had hoped to get a high flow measurement this summer. These are the most useful for determining flood discharge, but are the most difficult and dangerous to survey. Scheduling didn't work out any earlier, so we settled for surveying the comparatively lower flows that occur in the fall. The doppler worked great and we we able to survey multiple cross sections in less than half the time it previously took. Since we didn't have to stretch a cable across the river, it was also a lot safer.
The next day we surveyed the upper Delta River. Unfortunately, the doppler's control module failed, so we had to survey the traditional way (attaching the boat to a cable stretched across the river and using a mechanical meter to measure flow). Hopefully by next year, we'll be able to use the doppler at both sites.

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