There is one known way into the Cave Next Door (CND): the original dig site, It is recommended that this is the best way to reenter the cave while minimizing any possible environmental impact.

There is an approximately 30’ long trench from the creek bank to the ancient cave entrance, the result of subsidence caused by the cave flushing itself out. It was originally thought that the best way through this area was to remove the dirt in the trench, storing it on the surface, install a culvert or build a tunnel, then backfill with the removed dirt. After more careful observation, it seems that simply driving a tunnel through the loose dirt would be safer, more efficient, and more environmentally sound.

This method would be safer because the workers would not have to work in a trench, dealing with the hazards of supported walls. The tunnel would simply be built underneath and through the collapsed section, with simple drift mining methods, the walls and roof being reinforced with timbers. Any removed dirt would be put into the top of the collapsed trench.

It would be more efficient because less dirt would have to be moved to get the job done, and any dirt would only have to be handled once.

It would be cleaner environmentally because it appears as if the job could be done while totally avoiding the CND creek. It is observed that the water exits now from the right (west) side of the gate. This is because in the original tunnel there were loose rocks stacked on the west side. It is these loose rocks through which the water is flowing. Since the creek is flowing on the west side, a drift could be driven into the collapsed trench on the east side, avoiding the water. A tarp would be used to catch the dirt that needs to be removed, keeping any loose dirt out of the water. Once the drift is complete, a culvert could be inserted. Note that this is all work to be done by hand, with no heavy equipment included, thereby minimizing impact on the sensitive riparian area. This tunnel or culvert would serve two purposes: first, it would provide entrance to the cave. Second, it would provide a drainage for the spring, protecting the road from erosion consequences connected with the entrance plugging up at times of high runoff when the cave seems to be filled with water, which is indicated by ripple marks in the silt in all areas of the cave.

Another possible way into the original entrance would be to dig a vertical shaft at the most southerly end of the collapsed trench. Any dirt removed would go into the rest of the trench. The success of this method depends on how deep the water is backed up into the cave at the time of the excavation. If the cave is indeed empty of water it would be very easy to dig this entrance without impacting the water resources, but at the same time the possibility would still exist that a more complete plug-up could happen while someone was in the cave, possibly flooding the entrance and making escape difficult or impossible.

It is also proposed that the original natural cut in the talus slope to the creek will be lined with rock walls to the surface to prevent any further erosion. A roof would be laid on the rock walls, and then covered with dirt and duff to restore the cut to its natural condition. This is a part of the project that I feel could be started immediately, before further erosion occurs.

Since the entrance is located in a riparian zone, this plan would restore the creek bank to its most natural state, and reduce any further large-scale erosion from occurring. In effect, this would stabilize the forces that are flushing out the cave.

It should be noted that the CND entrance is not only in an area impacted by a road-cut, but also that the small patch of old growth forest containing the entrance is surrounded by harvested timber units, the proposed activity is most insignificant compared to other activities in the area. These harvested areas all show remarkable regenerative ability, probably a result of sound forest management and a strong, friendly environment, including soils and climate.

Much of the forest above the mapped section of the cave, the Canyon Complex, is an old partial cut. This forest has many large, healthy Douglas and white firs. Thinning has allowed sunshine to penetrate to the forest floor, resulting in a robust ground cover of grasses, rhododendron, ocean spray, Oregon grape, bracken fern, wild currants, and many other species useful to wildlife. These all make excellent habitat for small animals, birds, and deer. Bears are common, mountain lion are occasionally seen, and red foxes have become more common in the last few years. The forest is exceptionally beautiful in late spring and early summer when the rhododendron is in bloom. The lush grasses make wonderful nursery habitat for lactating does and their fawns. Unmapped areas of the cave system underlie more recently harvested units which show the same promise of prolific growth with more emphasis now on sun-loving plants such as black-caps and wild strawberries. Our activities in the cave, of course, have a negligible impact on these forests, but they are beautiful to wander and forage in.

After the collapse of the entrance in the spring of 2000, a thorough search of the area was made, looking for other entrances. The existence of airflow in the CND seemed to indicate that some kind of opening must exist. Any marble outcrop both on and off the monument was searched thoroughly with negative results. These included marble close to the entrance above the road and marble on the south fork of turkey Creek on the monument boundary. It was while searching the area in between that sinkholes were discovered in the north fork of Panther Creek. The lower sinkhole might be a fairly easy way into the cave. At this point it takes water through a rocky, six-inch hole in the bottom that connects to the water system in the cave. Altimeter readings also indicated that the cave could be within twenty feet of the surface, depending on how large a room the hole was connected to. This dig was started in the summer of 2000, and is now approximately 10 feet deep.

It was shown, by a simple measurement on a weir at the CND entrance, that water going down either sinkhole, or even a root-wad hole in this north fork of Panther Creek area, within eight hours comes out of the CND. This drainage seems to be one of the main sources of water in the cave. An entrance at this point would be extremely useful for exploration of the cave, for the simple reason that by going in at one point and exiting at another, not having to backtrack over the same route for each trip into the cave, will decrease human impact by 50%.

The sinkhole as it now exists is a 10’ by 10’ hole, about 10’ deep. It is proposed that this hole be reinforced with walls and cross-bracing to prevent collapse of the hard clay walls. This is another part of the project that could be started immediately to minimize any further erosion. Once the existing hole is reinforced and braced, it could be deepened, and then reinforced and braced further. In this way we would continue down until the cave is reached. A simple A-frame roof would be constructed over this hole with drainage ditches to divert snowmelt and heavy runoff. Again, as at the entrance, a culvert with an airlock door could be inserted once as a connection to the cave was established.

A simple roofed structure at this point would serve as a logistical support center and equipment storage, place for changing clothes, etc. The location, being off the road, is also more secure than the original entrance.

The discoverers of the cave believe that high stream levels caused by heavy rains and melting snow packs (1996, 1997, 1998) caused the CND to flush itself out at the entrance. This could have been accomplished by a "head" of water backing up into the cave and the subsequent pressure forcing the water out of the creek bank alluvium. More likely, the sump at the end of the canyon complex could be a siphon, connected to water reservoirs deeper in the cave that fill up at times of high water flow and when sufficient head is generated the siphon is started and the reservoirs are emptied, resulting in a surge of water through the cave and increased flushing out of the entrance. Perhaps the road helped the process by plugging up unknown and hidden "relief springs" that historically relieved this pressure. Probably this process has been at work for many hundreds of years.

Human activity in the form of work at the entrance, road building, and timber harvesting has obviously impacted the cave in various ways, but all these activities seem insignificant compared to the natural forces of nature in the form of fires, floods, ice or even log jams in the creek.

There are many questions to be answered about the Cave Next Door, including about the cave’s past:

What is there to be learned from a study of the sediments that form a plug to the natural entrance? How much of the history of the cave is recorded in these sediments? Are there any fossil pollens preserved in what appear in some places to be layers from multiple floods?

Not only is the cave at the evolutionary stage, so that it holds the story of its past, but it is also at a point where we can observe it changing as it evolves from a plugged cave to an open cave. We find it important to study these features now, before the natural flushing destroys them.

How does its chemistry change?

How does its biota change?

What are the rates of these changes?

How does all this compare to the same processes in the Oregon Caves, a historically open cave?

We can learn a great deal from the CND, and what we learn here can help us with the successful management of the Oregon Caves and other (explored as well as undiscovered) caves in the rich marble topography of the Siskiyou Mountains. The sooner these questions are answered about the Cave Next Door, the more meaningful the answers will become.

Respectfully.

David Hodges.

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Last modified: 08/06/07