Marble Canyon Engineers Trail: 27 March - 01 April, 2012

Approximate date 1950-51 a trail was built into Marble Canyon entering Shinumo Wash from Navajo Lands and traversing the Redwall bench to above Redwall Cavern. From an engineering camp supported by tram line from the rim above work was done here to evaluate the geologic structure and rock wall integrity as a possible dam site. The trail is still present and passable, leading to the camp remains and related works.

History

Not much is known, but the workers left their signatures and dates in several of the cement platforms.

How to Get There

Turn west from Cedar Ridge and follow road #6110 past Shinumo Altar, descending Eminence Fault and continue to the trailhead on the rim of Shinumo Wash. This is easy graded dirt-road almost all the way with a few rocky spots. The trailhead looks down into a minor bay at the south rim of Shinumo Wash. Several cairns and a disused track show the descent approaching the rim pouroff. Note that leaving a vehicle here and going hiking requires a permit for both camping and hiking (according to permit policy) obtained at the Cameron Tourism Service Center.

The trail turns the point going west along a ledge with a series of switchbacks through the lower Kaibab connected by built-up rock ramps. The trail is extremely well constructed and remains intact with slight washouts in the Toroweap and Hermit. The trail takes advantage of a Coconino slope with a brief cliff section showing some blast-work to make the last ramps down to the slope. Steel drills and anchors remain from the work done, and supporting a portion of the trail. One switchback of the original construction has fallen away. At the base of the Coconino cliff the trail makes a switchback west and begins a very long traverse descending the slope. Most of the way if the trail is not obvious here then you are not on it.

Trail to Silver Grotto

The principle characteristic which is somewhat unusual is that the trail avoids the wash bed and travels very high on the adjacent slopes in negotiating the Supai cliff section. If at any time you are not on the trail then you must relocate it -- there is no part where it would be sensible to choose to travel in the bed or any alternate route.

On reaching the bed the trail becomes briefly obscure where it immediately crosses to the north bank and across the point of a minor bend, back into the wash bed and onto the south slope in a boulder jumble. Rediscovering the trail where it returns to the south slope can be a challenge. Soon the trail passes close to the bed again and then up onto a ledge in the cliff, and then up onto the slope above the wash. At one place where it seems to end, the trail descends a rather unlikely looking crevice through the Esplanade cliffband and returns to the wash bed at a location with a rock overhang on the other side. Pass under this overhang shelter and ascend up onto the north slope and follow the trail for considerable distance through very large boulders. Cross the wash bed to the south and travel well up on the slope to a descent with switchbacks. Cross immediately and continue on the north slope until the initial Redwall exposure -- 3 pools, 2 easily acessible, should provide water most seasons when hiking here would be practical (not true for summer or early fall).

The constructed engineering trail climbs out from the Redwall crossing on the south side and soon rounds the point following the Redwall bench high in the Supai boulder slope. Fence Fault is an easy descent with a riverbank access but no beach. The delta of the drainage upriver is accessible also with a very minor downclimb. A very impressive quantity of gravel has been thrown into the river channel here and diverts the flow against the opposing cliff and makes a short-swift rapid. The raw load of stones spread wide with little vegetation makes it clear this is not a place to camp except in the most assured stable and calm weather conditions -- the potential to view a flash-flood or debris-flow could be impressive. Suitable camps are located on the Redwall bench overlooking the Fence Fault area downriver from the rapid.

The engineering trail continues downriver to the rim camp above Redwall Cavern, with an intermediate camp located opposite South Canyon. Again, there are some minor washouts and rockfall jumbles, but the trail remains intact and travel over this rugged terrain is relatively fast and easy. The bench is narrow rounding the point opposite Vaseys Paradise and the overlook closely approaching vertical to the other shore. Travel through here would be slow and difficult without this section of trail. Trail conditions improve as the bench gets broader and the Redwall surface becomes exposed.

At the Redwall platform on the rim above Redwall Cavern is the trail-end with the foundation and remains of the engineering camp. Iron loops embedded in concrete and cable sections lying in the wash below show that a tramway to the rim was setup to supply the camp.

Closely related to the camp fixtures is a site described as the 'Rod Access' where the engineers cemented steel hooks in the rock going down a nearby slot to the river. This feature can be found in the first accessible ravine when approaching the camp vicinity from upriver. Speculation is that this was to reach the river as a water-source for the camp, but the more likely purpose was exploratory drilling to assess the rock wall as foundation for a dam-site.

The trail ends at the camp but the possibility to follow the Redwall bench continues as far as Eminence Break. Travel is much slower and the next stop would be the riverbank at the Bridge of Sighs. The next two drainages upriver from here are significant obstacles in size, elevation, and terrain. The descent to the river is greater and steeper than Fence Fault, and again there is some notable climbing to reach the river camp.

Elsworth Kolb: "Then came a gloomy, prison-like formation, with a 'Bridge of Sighs' two hundred feet above a gulch, connecting the dungeon to the perpendicular wall" -- what imagination!! (photo at Mile 35.5).

On the occasion of our trip to Bridge of Sighs and return this was early spring after recent storms and we had hopes (even expectations) for rain-pools in the limestone beds. This turned out to be less than expected. Shinumo Wash and Tatahatso drainages are described as reliable resources in G Steck's Loops guide. With the landscape not being consistent with any surface water source, this would be limited to pools sheltered in the deep shade of these slots, and the main difficulty being access to them.

Shinumo Wash trailhead to the engineering camp is very rugged, but not exceptionally difficult. The off-trail sections between Redwall Cavern and Eminence Break require very strong navigation and trekking skills. The low elevation makes this area a good option for the cooler season and potentially very treacherous at other times.

After doing this trip out and back, it seems surprising that few hikers seem to be going here. Trail conditions are good, and the views and historical opportunities are excellent.

Reference Notes: Hiking Grand Canyon Loops by George Steck.