2015 Stream Flow Report

2015 was a very exciting year for the stream flow project. The batteries in the data loggers finally expired, so we had to send them in for replacement.  That cost the Conservancy a bit over $500.  We do not have any data for January and most of February.  The batteries lasted almost 7 years, so we got good service from them.  The predicted life depends on how often a data point is captured.  At one data point every 30 minutes, the predicted life is about 5 years.

There were two major spikes in the stream level.  One of them was in July just a few days before the NSS Convention started.  I was in the cave on the Saturday before the Convention when the water level at the ladder was over 18 feet.  That was actually DOWN 3 feet from the peak a few days earlier!  The water was touching the bottom of both of the bridges leading out of the landing area, and there was flow from the Thunder Falls shortcut over into Carroll River.  The water in Thunder River was completely ponded.

The second spike was near the end of December and was even higher.  The peak at the ladder was almost 24 feet.

One interesting observation from both events is the cave air temperature.  Normally the air temperature does not change even when the stream has a major change.  For both of these events the water rose high enough to change the cave air temperature.

Another interesting observation is how fast the water level drops after a major spike.  As an example – Thunder River was impassible the Saturday before Convention.  By the following Wednesday there were trips going to both Thunder Falls and Convention Hall.

The attached file contains all of the data and graphs from the year.  The .hobo files are what I actually download from the loggers.  They are the rawest of the raw data.  In order to view those files you need a copy of HoboWare.  A free version (which is missing some functions) can be downloaded from http://www.onsetcomp.com.  The .txt files are data exported from HoboWare.  The graphs are presented in both PDF and JPG format.

The water depth column in the TXT files is a calculated field.  The calculation is (water pressure – air pressure)*2.0373.  The constant is derived from the density of fresh water and represents the weight in pounds of 12 cubic inches of water.

On the rainfall graph, the vertical scale is in hundreths of an inch.  This graph represents about 70 inches of rainfall for the year.  When the line is vertical, it is raining.  A horizontal section means no rain.

If you have any questions about the graphs or data, please let me know

Bill Gee


2 Responses to “2015 Stream Flow Report”

  1. Nathan Says:

    Looks good Bill; interesting as always.

  2. Marty Says:

    Thanks for this 2015 report Bill. Good to have this data.