Stream Flow – Service Stilling Wells

Stream Flow Project Trip Report

Date of trip: 21 September 2008

Participants: Bill Gee (Trip Leader)
Andy Isbell
Jay Kennedy
Dale Curtis
Randy Bruegger

Time In: 9:30am
Time Out: 1:30pm

Area Visited: Carroll Passage upstream of Water Barrier

After a high water event in March, the silling wells for both Thunder River and Carroll River needed work. The purpose of this trip was to service both of the stilling wells.

The stilling well in Thunder River was just a stub. It sufficed to protect the data logger, but because the water over it was moving the depth reading were slightly inaccurate. The stilling well in Carroll River is mounted on a large but loose rock. The high water event in March undermined the silt it was resting on, causing it to tip at about a 45 degree angle. This does not affect accuracy, but it did produce a singularity in the data.

I was first up the hill about 8:30 with the ropes to rig the shaft. I opened the cave and hung a rappel rope provided by Jay Kennedy. I also downloaded data from the rain gauge logger on the silo. Everyone else showed up by shortly after 9:00am. Jay rigged a haul line for gear using a second rope.

I was the first person down at about 9:30. We then used the haul line to drop some gear including the new stilling wells. By 10:00am everyone was in the cave.

The first stop was the stilling well in Thunder River. The river was running about 3 or 4 inches higher than normal. I downloaded the data logger, then we removed the stub stilling well and bolted a new one in place. We drilled three holes in the ceiling of the cave near the stilling well. A plastic wedge anchor was placed in each hole. A short strap of aluminum was attached to the wedge anchor. We ran stainless steel wire from the aluminum strap to the top of the stilling well. After pulling the wire tight, the top of the stilling well now does not move.

From there we traveled down Carroll Passage to the stilling well in Carroll River. This well is located just downstream from the Bear Claw passage near the Totem Pole formation. I downloaded the data logger. While Jay, Randy and Dale disassembled the existing well, Andy and I scouted around for a better location. The stream through this section has several feet of silt on the bottom, so we cannot bolt the stilling well to bedrock.

Eventually Andy and I found a spot about 100 feet downstream from the previous location. The new location is just upstream of a place where the stream goes under a rock shield for about 15 feet. The main attraction was several solid rocks nearby which could be used for anchors.

We moved the anchor rock, bolted the new stilling well to it, and put it in place. We drilled four anchor holes around the site. Three of them were strung with wire anchors to the top of the stilling well. The fourth was used to tie a line to the data logger.

Everyone packed up and we went back to the ladder. Dale and I took a short trip over to Thunder Falls to see how the water level was affecting it. Thunder Falls was running nicely. Dale took a few pictures, then we went back.

Andy, Jay and Randy climbed out first. They dropped the haul line. Dale and I attached some packs to it which were then hauled out. Dale and I climbed out last. We were out of the cave by about 1:30pm.

Bill Gee

PDF – Graph of Carroll River data

PDF – Graph of Tunder River data

CSV file – Barometric data logger

CSV file – Rain Gauge data

CSV file – Carroll River data

CSV file – Thunder River data