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Rock Lake Explorations

Discussion in 'Rocky Mountain Region' started by boulderjohn, Sep 10, 2017.

  1. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    I posted a report of our exploration of the west line at Rock Lake in Santa Rosa, NM, in this thread: Rock Lake Trip Report. I am going to use this thread to detail further explorations as time goes by.

    Yesterday we made a preliminary exploration of the north end. As reported earlier, the existing north line descends at a slope we estimated to be at about 30°, starting on a ledge at about 40 feet. Making good use of high school geometry, we estimated that it hits the bottom at about 135 feet out from a vertical drop from that ledge, making it less than ideal as a starting point for north wall diving. So we got a large block and new line and dropped it straight down from that ledge. With a weight as big as the one we had and all that depth, this was not an easy operation to do safely, and it took us a while to get it done. So now there is a vertical ascent/descent line at the north end to use as a starting/stopping point for dives.

    The line did not play out as far as we expected it to, so we were not sure what we would find at the bottom. When we got there, we found that it had landed on a surprisingly steep slope. We moved it down the slope a little, which stirred up some silt. We then tied a line off and headed north, with the goal of finding how far back the overhang goes. One of us led the way with a compass, and the second diver followed close behind with a reel. I was last in line, carrying a bundle of PVC stakes which I used as attachment points in the deep silt for the line we were laying. I sunk them into the silt and then wrapped the line. I was working in zero visibility because of the very fine silt that was stirred up by those ahead of me. I just kept one hand on the line and shoved in a stake every now and then.

    We came to the wall much sooner than expected. We were thinking it might be 100 feet based on experiences in the shallower sections, but we did not come close to that. We entered a large boulder field, tied off the line, and worked our way back to the new descent line. We made another effort to move the block down the slope, creating another massive silt explosion, and then made our ascent. The deepest part of that experience was only about 268 feet--we were expecting a little more.

    On some future date we will go back to see what we actually did and what that area looks like. In my role of bringing up the rear, I pretty much never saw a thing.

    Today we will be looking at some features at a shallower depth.
     
  2. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    Another focus of our recent explorations has been the vents at the bottom of the east line. (By vents I mean openings in the rock-strewn floor through which the water enters the lake.) The bottom at that point is much shallower than the rest of the lake--only 180 feet at the tie off. On our October trip, Brett worked hard on the vent right at the tie off, pulling a lot of silt out of it. On his last dive, he got his legs into it and kicked to raise the silt, hoping the flow would force it out. We checked it out this past weekend, and we see that what he accomplished through this was creating a silt mound at the entrance. this is an area for future work.

    The second vent, about 20 feet away, has loose rocks all over it, covered with silt. On this trip I moved 5-6 of them. Again, I will have to come back in the future to see what I accomplished, since doing so raised enough silt that I could not see the results.
     
  3. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    On our October trip, Brett and I went down the new north line, went to the end of the lateral line we had laid northward, and added more line to the west. We were hoping to find more depth, but we did not.
     
  4. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    This past weekend, David and I hoped to extend the old, existing line leading northwest from the bottom of the east line. We knew from the past that the line just stops, its end lying loose in the silt. We hoped to extend it to a deeper section we were told was there but still haven't found. When we reached the end of the line, I tied off a spool and continued on, going in whatever direction looked most promising for greater depth. The bottom was all soft silt, with very little contour. After a while and some unexpected complications, we were at the end of our planned turn time, and there was nothing remotely good for tying off. I started reeling in the spool and heading back, but after a few minutes I blundered into something unexpected--the new north line. I quickly cut my line and tied off. So now the east line connects to the new north line. that was not what we were hoping to do, but it is better than what we were hoping to do.
     
  5. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,635
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    This past weekend we tightened up the new line connecting the north and east lines and placed rocks under the old line in places where it had become buried in the silt. You can now easily and safely find your way from one line to the other. David and I dropped on the north line and then ascended the east line to do this. We arrived at the east line much sooner than expected, and we spent some time checking out the vents for further exploration plans.
     
  6. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    It's been a while since I made an update, so here goes.

    The old north line sloped toward the middle of the lake, and although we could estimate that distance using triangle properties, we could not be sure, lacking a protractor with which to measure the angle of descent. This past weekend, we descended that line and sent up a bag from the bottom (270 feet), thus discovering that it is barely north of an imaginary line running from the east steps to the wet line. That is actually not far from what our attempts at high school geometry had predicted, but much farther into the lake than I believe most people thought.

    We then ran a line from the bottom of the old north line to east line. Now all we have to do is connect it to the west line, and we will have created pathways from all descent points to all ascent points.
     
  7. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    On our most recent trip, our most notable exploration was heading south west from the east line, following a compass heading into territory none of us had seen before. We were well rewarded for this. About 2/3 across the lake we found two new vents, one of them spitting out tiny pieces of gravel. Both went straight down. We then continued to the west and made out way to the west line for the ascent. We should be able to find those vents again, this time laying line to them.

    Finding these vents is significant. They do not appear on any of the old maps we have. More importantly, they are at the bottom of the lake. The other vents are mostly at the top of the débris pile on the east wall, nearly 100 feet above the bottom of the lake. Assuming the débris cone was formed by the collapse of the ceiling at some unknown time in the past, it is hard to imagine how the vents are fed through that much broken rock. One of them seems to lead into the wall, suggesting the possibility of a shallow chamber next to the lake. The newly discovered (at least to us) vents are more likely to lead more directly to a chamber. That is how it is at the nearby Blue Hole, were the vent at the very bottom leads directly to the cave beneath.
     
    longk14 likes this.
  8. KevinNM

    KevinNM DIR Practitioner

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    270 feet before you get to the cave is a really, really serious dive. Heck, 180 feet before the entrance is pretty damn serious. But it’s doable, I have met people who do that kind of thing fairly often.
     
  9. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    I don't think any of us are the gung-ho types who would ignore these realities.

    About a year ago when we were planning our dives, a couple of us realized we were talking about a dive that was "only" going to go to 200 feet, as if that was nothing to be concerned about. We had a laugh, slapped ourselves in our respective faces, and then gave the dive the respect it deserved.
     
    Nick Steele likes this.
  10. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,635
    17,070
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    Today Brett and I connected the line in the middle of the lake to the west line. It proved to be an easier task than expected, so we had more time. We headed north along the west wall and discovered a vent just north of the west line. A little north of that we hit our deepest depth in that lake so far--280 feet.

    That means that we have navigation lines that can take you from any of the ascent/descent lines to any of the other ascent/descent lines.

    I was getting a little chilly late in the dive, and it was very nice to get above the 40 foot stop and bask in 75° water.
     

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