The summer of 2014 will be remembered by most Fairbanksans as the rainiest summer in memory, but for those living on Goldstream Creek, it marks the first time in at least 30 years that the Creek went over the banks. It started with completely saturated ground from near-continuous rain in late June and was followed by more than three inches of rain falling during a single 24-hour period on July 1st and 2nd.
By the evening of the 2nd, the Creek had risen to the banks, washed out our 18-year old log bridge, and eventually flooded our property to a depth requiring chest waders to make it out to the back cabin. It crested in the early morning hours of July 3rd, and took the entire day to return to the confines of the Creek bed.
Here are a few videos of the flooding, including one showing our bridge washing downstream in front of the back cabin.
Since the flood receded, we cleaned up the mess, repaired the foundation under the arctic entryway, and worked to raise the bridge and lift the back cabin higher off the ground so it is no longer in danger of being flooded in the next event.
Raising the logs back up to the banks was an exercise in how to carefully lift and move very heavy things without an overhead crane. The technique is based on a pair of 4x4’s bolted together at the top to form an arch. The bipod sits on the bank and leans over the edge, with one rope winch keeping the bipod from falling into the Creek and another rope winch attached to the log through a pulley hanging from the top of the bipod. For it to work, there needs to be a greater than 90° angle at the pulley so that the action of tightening the rope connected to the load will pull the top of the bipod down (but instead, lifts the end of the log). Here’s a photo taken during the first lift.
The cabin was lifted using a pair of “railroad jacks” on the ends of the bottom side logs. Amazingly, the entire cabin could be picked up from the very ends of the logs, and in two days we had the cabin up ten or eleven inches sitting on large pressure-treated pads.
Earlier this week we had another unprecedented rainstorm that dumped more than two inches of rain in less than 24 hours, breaking the daily record, and giving Fairbanks more than our average monthly rainfall for September in a single day. The following graph (PDF version) shows the water level in the Creek following the storm.
It took just over 24 hours for the flood to Crest, and then another three days to come back down to the level it was before the storm. We observed a similar pattern in the July flooding event, but I can’t seem to find the notebook where I recorded the heights (and then depths once it was over the banks). It is quite remarkable how quickly the water rises once it begins; when we got home from work on July 2nd and the water was only a third of the way across the dog yard, I still thought the water would be contained. But it continued rising and rising. It will be interesting to compare the pattern from July to September if I can find those numbers. Having a sense of what we can expect from the Creek when we get a big rainstorm is very valuable information.