12/07/02 – Lerch/Brown (Convention Hall)

Survey Report – December 7. 2002


UL1 Survey

Bob Lerch – book, sketch, instruments

Roger Brown – instruments, lead tape

Time in Cave: 13.25 hours

Roger and I got in the cave at 11:30a. We coordinated an out time of 1:00a with the other teams, and then headed directly to the UL1 (Convention Hall) survey. Last time we wore 6 mm wetsuits which discouraged exploration of the high leads. So, this trip we only wore cave suits and brought in additional clothes to put on as needed. This strategy worked well, and we were both generally warm throughout the trip.

Upon arrival, we began exploring the upper leads near the beginning of the UL1 side passage; we needed to figure out where we could safely climb up and how we would tie it in with the lower survey. Eventually, we both found different, but sketchy climbs to the upper level, which is about 20-30′ above the stream. The passage is about 4.5-5′ tall and 10-20′ wide, with a downward sloping floor. Roger headed back towards main passage, where the upper level soon intersects the main passage. I headed into the passage and found virgin upper level cave, with an awesome decorated room (20′ long by 8′ wide). The “hanging garden” room was filled with small stalags, spathites, soda straws, rimstone pools, and flowstone. Heading into the cave, I was walking on virgin sand and clay sediment floor. I was able to take the upper level to where it intersects a large, decorated dome room. Realizing that the stream level survey will also head into the dome room, I now knew we could tie-in there. At Rogers end, through dumb luck, we can tie-in at the first station (UL1A).

One thing I am becoming keenly aware of in Carroll is the danger of the upper level passages.  They are typically a series of meanders (with solid floors) alternating with potentially unstable hanging ledges, all covered with old sand and clay deposits. Sometimes you were on a meander and couldn’t t see the stream at all; other times you find your self on a ledge overlooking the stream 20-30′ below. The rotten Gasconade dolomite poses some real hazards throughout this passage. Foot and hand holds must be tested as it is common for large chunks to break off. The overhangs can really be dangerous; it would not be surprising if an entire ledge breaks off, so we were really cautious when climbing around. The danger of the upper level passages is even more of a concern the further into the passage you go. The stream cuts deeper, and ledges were often 40′ above stream level.

With our new found understanding of the upper level passage, we planned our strategy for the day. We decided to continue mapping at stream level and then on in to the decorated dome room (we don’t know if this is Convention Hall or not, but it is awesome). We would save the upper level for another day, but we at least have an idea of how to survey it for a future trip. We moved fairly quickly through a series of short shots in convoluted stream canyon passage until we reached the dome room. Here, we again had to look around to determine the best way to survey this increasingly complex passage. We determined that we needed three survey lines to map the dome room well and set us up for future work. First, we mapped around the right wall with the final station (UL1PE) setting us up for continued upper level survey past the dome room. Next, we headed from the stream level up into and through the room, ending with a station (UL1P’A) that will set us up for the mid-level survey. The third survey through the dome room will be at the stream level, which continues under a breakdown pile and pops through to the dome room and defines the left wall. We did not get the stream level started, but we left a station for the next trip. The steam level will be the main survey line as it actually represents the going passage; the bulk of the dome room is really a large meander.

In total, we shot 14 stations, but managed only about 280′ of survey. A somewhat disappointing amount, but we will really have a nice accurate survey of the dome room, and we are well positioned for future work. Moreover, a two person survey team is not usually going to get as much footage as a team of three (lame excuse time). Roger and I have worked together enough times that we can run a decent two-man survey. The LED lights included with the CCC survey stuff were real helpful for a two-man team since Roger could usually set the lights on both stations, allowing him to shoot the fore- and backsights. I could spend most of my time recording data and sketching, without the bother of reading instruments very often. Another helpful thing, I find, is to have two measuring tapes. That way, one tape can be left between stations for the sketcher, and the instrument person(s) can move ahead to the next shot. This keeps the instrument people busier and happier.

As you can tell, this trip was largely a strategy session, but to me it was worth the time to really assess how to map this complex stuff. Roger’s experience and input were very helpful, and we’ve at least got a plan. Carroll is another level of survey challenge for both of us, and it really requires some contemplation. The footage may come slowly for awhile as we get adjusted to mapping such complexity.

Biology note

We counted 9 cavefish along the UL1 stream through the course of the day. In all cases, the fish were in pools, typically with 2-3 individuals per pool. Our level of effort was minimal. We generally spent 30-60 seconds looking in a pool, and we found them in three of the four pools in which we looked.

Comments are closed.