Nambe Falls Dam Safety Concerns

Nambe Falls Dam Safety Concerns
January 2004
Andrea Glover
Technical Services Division
Albuquerque Area Office
On December 22, 2003, I aided Chris Torres of Surveying Services in performing the semiannual settlement survey at Nambe Falls Dam. While there I experienced three situations that
actually made me uncomfortable while performing my duties. I feel that there are serious risks
associated with this job; risks that can be easily mitigated.
The job requires carrying the T2 theodolite to three sites, affixing it to a set pier, and then
sighting on points on the dam. Below is a plan view of the dam with the three setup sites
located in blue.
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Site 1
Photo 1
Photo 2
CONCERN 1: Getting to Site 1 (shown on Photo 1) involves hiking down the riprapped face of
the earthen portion of the dam, through a gate, and then up a hill to the theodolite pier.
Throughout this hike, a person must carry the T2 and the T2/pier adapter base. The T2/pier
adapter base is about six inches in diameter and weighs a pound or two. The T2 is large and
weighs 17 pounds. See Photo 2. Having both hands full, one with a heavy, cumbersome
object, while walking down (and back up) a steep, slippery slope is dangerous. The chances of
slipping and falling are great. This is not only of concern since it can cause bodily harm, but
also because it would damage the T2 theodolite. An example of the riprap slope can be seen
on Photo 9.
SOLUTION: While the dam face cannot be changed, carrying two items while traversing the
face can be. A backpack should be purchased that can hold both the T2 and the T2/pier
adapter base. With these items in a backpack, the trek will still be tricky, but both hands would
be free to help you balance and steady yourself.
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CONCERN 2: In order to reach Sites 2 and 3, a person must drive around the reservoir, park
near the top of the hill just north of the dam, and walk down a stairway that has deteriorated
extensively. Photo 3 shows the locations of the parking area, Site 2, and Site 3.
Parking
Area
Site 2
Site 3
Photo 3
This stairway is in great disrepair. There are sections where steps are missing. The handrail is
sagging and falling down. There are nails exposed. Photo 4 is taken from approximately
halfway down the stairs, looking back up. Photo 5 is taken from the base of the stairs, also
looking back up. Photo 6 shows the condition of the stairs at their base.
Along the base of the stairway is a wooden walkway. It is very precariously attached to the rock
face. Walking to Site 2, there are portions where there is a clear drop off directly under the
walkway. The handrails on the walkway are in better condition than those on the stairway, but
definitely not in good enough condition to trust falling against. Photo 7 shows the walkway to
Site 2. Photo 8 shows the walkway and the pier at Site 2. Photo 9 shows where a person
would fall to should this walkway fail. During this survey, there was ice on portions of the lake.
Once again on this hike, both hands are tied up with the T2 and the T2/pier adapter base.
Portions of the stairway were useable, but when you reached a failed portion, you must step off
of the stairway onto a rocky slope. Having the backpack mentioned in Concern 1 would be
beneficial in this location also.
SOLUTION: The stairway must be repaired or replaced. If the upkeep on wooden stairs is not
feasible, then metal stairs should be considered. Concrete would be more durable, but during
wet, freezing conditions, concrete stairs would create their own set of hazards. Open grate
metal stairs would be durable over time and would be safe during all weather conditions.
Asking any employee (and Government contractors) to use these stairs is negligent at best.
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Photo 4
Photo 5
Photo 6
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Photo 7
Photo 8
Photo 9
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Photo 10
CONCERN 3: When at Site 2, there is no fall protection of any sort. Photo 8 shows how Site 2
sticks out on a small pinnacle, while Photo 10 shows more closely the footing and lack of work
area surrounding the theodolite pier. Talus can be observed falling from this site. Once again,
Photo 9 shows where one mis-step will lead.
Falling is main concern at this site, but there are other interconnected concerns. If you fall,
someone might not see you. It is common practice during this work for there to be two people
on site. One USBR person and one contract surveyor. At best, the surveyor is on the southern
dam crest and may see someone fall. At worst, the surveyor is in the process of driving from
the parking area to the dam crest and cannot see an accident occur. The trip from the dam
crest to Site 2 takes approximately 15 minutes. So even if the surveyor witnesses the fall, they
are 15 minutes away from helping the person who fell. Assuming the person survived the fall
with minor injuries, they still need to swim to shore and attempt to pull themselves out of the
water. Remember there was ice on the lake during this survey. According to the dam tender,
ice is common on this lake through much of the winter. Also look back at Photos 8 and 9. If
someone sees the accident and comes to render aid, that aid would be very difficult to give.
Traversing the rocky slope beneath Site 2 is nearly impossible. While I was at the site, no
ropes, flotation devices or other aids were available.
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SOLUTION: Handrailing and stable work area need to be installed around Site 2. This could
be done at the same time as work on the stairway. Once a handrail was in place, the risk of
falling would be greatly minimized. JHA’s should also be established for this duty. The person
performing the work should consider keeping a rope in their vehicle that can be accessed
should an accident occur. Flotation devices probably are not any help since the time it would
take for someone to get to the person is too great.
Many of our field duties have inherent risks that cannot be mitigated. Personnel performing the
job must be aware of the risks and knowledgeably work around these risks. However, I cannot
think of another situation that made me as uncomfortable as I was on this job. Being around
heavy construction equipment, scaling quarry walls to look at the geology, or working in the river
are all dangerous, but none of them bother me. Walking across that wooden walkway is not
something I ever want to do again.
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