High Tide at Pompeys    

High Tide At Pompey's
or
Timing Is Everything, But Good Judgment Helps

Written for the SCAG newsletter somewhere in the vicinity of 1997.

I've taken long enough to get around to writing this that the actual date escapes me, but around the third week of September I made the very wise choice of aborting a Pompey's trip when I discovered that it had apparently rained harder in some places than it had in the place where I had spent the day. The group I was with consisted mostly of beginners with little or no caving experience, and we had already driven to the cave when I made this discovery; since they didn't know any better, they were quite willing to continue despite the impressive (and powerful) river that was not merely flowing past us, but was in fact grudgingly parting in order to flow around my thighs as I stood at the bottom of the ladder.

The purpose of this article is to explain something of the basic nature of Pompey's and to describe the very impressive hydrologic activities, which rapidly followed my decision to abort the trip. For those who may be unfamiliar with Pompey's I'll start with some background information.

The most significant feature of Pompey's, which at almost 3900 feet is Ulster County's longest known cave, is the presence of Kripplebush Creek in most of the cave's passages; normally one can hear the stream several yards away from the entrance. Several times a year the cave floods to the ceiling, and the creek makes a presence in all the passages, as well as in the surface streambed; on a few such occasions I have seen huge quantities of water gushing into the Ladder Entrance, and I have seen still huger quantities gushing on past the entrance and down the streambed. I have often wondered what it would be like to see the inside of the cave under such conditions, but never actually tried to find out, since I thought that even with a life jacket and a rope tied to a really big tree it would be completely suicidal to do so. Under normal flow conditions the entire creek insurges at the upstream end of the cave, leaving a dry streambed above the cave, and then resurges about 1000 feet downstream of the known cave passage. At these times there is a calm pool of water just upstream from the ladder, and the ladder itself is out of the water. Typically, my feet would be almost two feet above the water when standing there.

The times of flood coincide with a heavy snowmelt or a substantial quantity of rain, usually over a period of days. On this particular date I had seen only a light but steady rain the preceding day where I was working. Once at the cave it became apparent that the watershed for the cave had seen much more rain than I had. I should point out that I have been to Pompey's on numerous occasions of moderately high water, when it can be quite exciting to work your way through the current, and there have been times that I chose not to head downstream from the Ladder Entrance because I was concerned that it might prove too difficult to return against the force of the current.

About midway between the upstream and downstream ends of the cave is a constriction known as Wigger's Way; I have always suspected that besides impeding cavers that aren't fairly thin, this is also an impediment to water flow at high levels.

Being optimistic, I suited up upon our arrival and lead the group up the dry streambed toward the entrance. Unfortunately, the streambed wasn't actually dry, but had a few small streams running in from minor drainages, and we started by wading through an ankle deep puddle; unusual, but no cause for immediate alarm. Once we got within 50 feet of the entrance, however, we could hear the unusually loud roar of the creek, and I knew that the water level was quite high, and I began to suspect that it might even be higher than I had ever seen it, at least from the inside of the cave. I went down the ladder to confirm these thoughts, and found myself standing in a river that reached mid-thigh at the very base of the ladder. I am pretty certain that this is close to a full foot higher than on any previous trip where I actually continued. The normally calm pool was a swiftly flowing current, and this current appeared to extend all the way to the wall of the passage. As long as everybody had come along, I brought them down the ladder and herded them onto the rocks next to the ladder so that they might at least see the entrance area. I asked if everybody was up to continuing, and for any of several possible reasons they were willing, except for the one other person who actually had significant caving experience. The chief reason was certainly that, being first timers they simply had no idea of what could happen; it is also possible that they placed way too much blind faith in my judgment and leadership, and they obviously took me seriously when I asked. I pointed out that what I seriously thought was that the conditions were such that if somebody slipped they would die, either from actual drowning or from being battered to death as they were swept downstream. Mostly out of curiosity, but partly to let them think that I really didn't want to unnecessarily cheat them out of the trip, I ventured a short distance upstream while hugging the wall. Sure enough, the current was somewhat strong right against the wall. I broke the news that we weren't going to be seeing any more cave that night, and we retreated up the ladder.

As long as we were there, however, I figured that we might as well look around the surface, and see what the other entrances looked like. We walked up the streambed (which was in fact dry in this area), pausing in a low spot upstream from the entrance to look at the Jewelweed. For those familiar with the cave, this spot is roughly above the Kilroy Room. Continuing toward the Fallen Slab entrance, we encountered some surface flow, and crossed the stream in ankle deep water. The excitement began when I located the Fallen Slab entrance, and found it completely occluded with branches and other debris; I brought the group closer, and just as I opened my mouth to say "don't step off of the rocks", somebody did, breaking through the obstruction, and allowing us to observe that the water level was right up to the top of the entrance. Fortunately my companion did not actually fall in, but merely put one leg in the hole; more fortunately the water was ponded and there was no real flow into the entrance. He could not have been sucked in, but he did give me a good scare. We retreated back across the stream, and although the water didn't seem any deeper, I thought the current was stronger than five minutes earlier. As we walked downstream I became convinced that we hadn't walked in the water for that long a distance. When we reached the three foot ledge above the low spot with the Jewelweed I was positive that the water had not been flowing over the ledge as it was now, and we could all see that if we were still standing amidst the Jewelweed even Frank, who is 6'6", might not have had his head above water. I formed two three person tripods and we carefully crossed the stream again, and returned to the Ladder Entrance to find an impressive waterfall pouring down the ladder. It was now perhaps twenty minutes since we had left the ladder. If we had been downstream of the ladder we would either be dead or about to die, and if we had been upstream of the ladder we might have been swept away while attempting to return to the ladder. I was able to look down into the entrance, and it looked as though the stream wasn't any higher than it had been. On top of everything else there was a stench of sewage.

I suspect that we happened to arrive at exactly the right time to watch the confirmation of my theory about what happens as the water level rises. I believe that the stream flows entirely within the cave up to about the flow level we initially encountered, and then begins backing up at the constriction at Wigger's Way. This causes the upstream portion of the cave to backflood, and the stream begins flowing on the surface, where it is now able to sink in the entrances that are downstream of Wigger's Way. The increased hydraulic head also must force more water through Wigger's Way. Since the stream is then able to sink in the Impasse Entrance, and more water must be coming through Wigger's Way, I am puzzled that my look down the ladder didn't reveal an obvious increase in the amount of water flowing past the ladder; I am very curious about how full the various parts of the cave were at that particular point, but as I mentioned previously, it would most likely be the last thing I ever learned.

I may have been a bit over confident about my familiarity with Pompey's (I've literally been there over 150 times), and it's good to find that I can still learn more about the cave. I have always felt that Pompey's can carry a substantial amount of water while still being a safe place to go, so it its good to have seen how the stream behaved at that kind of water level. Since I hadn't seen any rain for about two hours before we got there, it was also a reminder that we were experiencing the results of what had occurred some hours earlier some distance up the watershed. Flash floods, like other natural disasters, always happen in other places and to other people, such as boy scouts in Utah's slot canyons. It is sobering to see it happen so close to home. It also leaves one lingering question: how fast was the water rising right before we got there, and what if we had shown up 30 minutes earlier, and chosen to spend an hour in the upstream part of the cave?