2025 Stream Flow Project Report
This is the annual report for the Carroll Cave Stream Flow Project. The discussion covers calendar year 2025. There is an attached ZIP file at the bottom of this post which contains all of the data and graphs for the year.
Carroll Cave recorded three flood events during 2025. The first was in early April, the second in late April and the third in early June. The late April event was the biggest of the three.
Flood one: The stream started rising in the early morning of 4 April. By late afternoon the level at Thunder River was almost 4 feet. It ebbed for a few hours, then came up again to a maximum of just over 4 feet during the morning of 6 April. The level subsided slowly for about two weeks, getting down to 1 foot on 19 April. The water level below Thunder Falls peaked at about 13 feet for this event.
Flood two: The stream started rising in the early morning of 19 April. It went up to about 2 feet and stayed there for a day and a half. Starting in the evening of 20 April the stream rose rapidly to just over 13 feet in 24 hours. The level fell almost as fast as it came up, going under two feet just 48 hours later. The level continued to fall for the next few weeks but never got under 1 foot. The water level below Thunder Falls peaked at over 22 feet for this event.
Flood three: The stream started rising in the early morning of 4 June. A minor peak of just over 2 feet was reached late that morning. The level ebbed a bit, then rose to just over two and a half feet in the evening of 6 June. The level fell slowly to 1.1 feet on 20 June and continued to fall very slowly for the rest of the year. Below Thunder Falls the level peaked just over 6 feet.
One of the graphs I created shows the stream level along with rainfall events. The early April flood has a clear rain event associated with it. The major flood two weeks later has some associated rain, but not as much as the first event. Data from Climate.com (radar estimates) have a more obvious rain event at that time. The third flood event has only a small rain event.
There were two more big rain events, one in mid-July and the other in September. There are no stream level changes associated with these rain events.
The rainfall graph shows three lines from Climate.com and one from our rain gauge on the silo. Our rain gauge recorded about 10 inches less rain over the year than estimated by Climate.com. There are two possible explanations.
First, Climate.com issues a rain report only once per day and it is to the nearest 0.1 inch. I suspect they always round their estimates up – never down. The over-estimates accumulate during the year.
Second, it is possible that the silo rain gauge was not in the heaviest rainfall for some of the events. The two April rain events look like that happened.
Climate.com gives us three estimates. One is for a field roughly centered on the silo. Another is around the natural entrance and the third is west of the silo about 2 miles.
The plan for 2026 is to continue with what we have been doing. I do not anticipate any of the data loggers needing a battery change for several more years. The July trip to service the loggers might be later in the month due to conflict with NSS Convention scheduling.
Mateo and I have been talking about a method to get real-time reporting of the stream level to a web site. If that could be done, it would make decisions about whether to abort a trip much easier. There are two big problems to be solved. Finding suitable sensors for the cave is an issue. The bigger problem is finding a gateway to the Internet that is affordable. With a budget of $500 per year we could probably do it. I don’t think the data is worth that price.
So far all we have is ideas.
Bill Gee