2012 Stream Flow report

During 2012, there were several major rises in the stream level in Carroll Cave. All occurred in the spring, from late March to mid-May.  The second half of the year saw no stream level events.  The stream level fell very slowly to what is probably close to a record low level at the end of December.

The rain gauge logger shows two major rain events.

March 20 5:00am to March 21 11:30pm – 4.71 inches
April 13 4:00am to April 15 11:30pm – 4.11 inches

There were several more events in early and mid May of around an inch and a half.

The level in Thunder River began rising at about 9:30pm on March 20.  The crest was 11:30am on March 22 at just over 11.5 feet.  Normal stream level in Thunder River is just over 1 foot.  The crest receded almost as fast as it came up, going under 2 feet about 3:00am on March 24.

The corresponding change in UL2 was rise beginning at 11:30pm on March 20 and peaking at 3.6 feet at 6:00am on March 21.  The stream briefly went below 1.5 feet, then rose again to a peak of 2.5 feet at 1:30am on March 22.   By noon on March 23 the level was down to 1.2 feet.  Normal level is about 0.8 feet.

In Carroll River this event began about 9:00pm on March 20.  The peak was 1.6 feet at 9:00am on March 21.  There was no double peak.  The stream was under 1 foot by 6:00am on March 23.  Normal level is about 0.8 feet.

The second event started raising the stream level at 12:30am on April 14 with a peak of just over 2 feet at 9:30am on April 15.  It is very interesting that two rain events of similar magnitude produced such different changes in the stream level.

In UL2 this event began at midnight on April 14, going over 2 feet in less than 2 hours and peaking at 2.3 feet at 3:00am.  There was a short dip around noon, then back up to 2.4 feet at 2:30pm.  The stream was back under 1.2 feet about 7:00am on April 16.

In Carroll River the stream started rising at midnight on April 14.  It was not much of a rise, peaking at 1.3 feet at 2:30pm and falling below 1 foot on the morning of April 16.

As usual, every significant change in stream level was accompanied by a change in the water temperature.  The swings are not huge – less than 1.5 degrees Fahrenheit.  Still, when the water temperature normally varies by less than 1/10 of a degree, this is very noticeable.