9390

• UCREFRP Catalog Number: 9390
• Author: Webb, R. H., T. S. Melis and R. A. Valdez.
• Title: Observations of Environmental Change in Grand Canyon, Arizona.
• USFW Year: 2002.
• USFW - Doc Type: 02-4080,
• Copyright Material: NO

Table 3. List of known driftwood fires in Grand Canyon, 1937-1964.
Year Date Diarist Location Relative Size
1955 Jul 5 P. T. Reilly Spring Canyon Large
1955 Jul 13 F. Wright Hance Rapid Signal fire
1956 Jun 19 P.T. Reilly 24 II2-Mile Rapid Unknown
1956 Jun 20 P.T. Reilly President Harding Rapid Unknown
1956 Jun 30 P.T. Reilly Fern Glen Canyon Large
. 1956 Jul 13 F. Wright Hance Rapid Signal fire

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were. The Old Timers remarked on the severe beach
erosion in the reach downstream from Nankoweap
Rapid (river mile 53-54) and at the mouth of the Little
Colorado River (mile 61.5-L), Elves Chasm (mile
116.5-L), Stone Creek (mile 131.9-R), Tapeats Creek
(mile 133.8-R; Fig. 3), Deer Creek Falls (mile 136.1-R;
Fig. 4), and the mouth of Kanab Creek (mile 143.5-R).
Comments about beach erosion decreased
downstream of Havasu Creek (mile 156.9-L), which
mayor may not be significant. They either continued to
see eroded bars and felt it not worth additional
comment, or the bars may not have been as eroded as
upstream, as reported in Schmidt and others (1995),
and Webb (1996). Although the Old Timers noted the
increase in riparian vegetation, none of them associated
this increase with a lack of campsites. Most of their
comments came at heavily used sites, not generic sand
bars. In no case did the Old Timers specifically
contradict our interpretations of historic photographs.
Both Reilly and Beer lamented the loss of
camping beaches during trips they made in the 1980s.
During a 1984 trip, Reilly observed erosion of sand
bars at Tuckup Canyon (mile 164.5-R), National
Canyon (mile 166.4-L), and Fern Glen (mile 168.0-R).
Beer, in particular, remembers the sound of sand bars
calving off into the river as he swam by in April 1955.
Rigg noted that several sand bars he had camped on
were now either reduced or eliminated. Nichols
commented on the reductions in sand bars at the mouth
ofthe Little Colorado River (mile 61-L), Elves Chasm
(mile 116.5-L), and Deer Creek Falls (mile 136.2-R).
Cross II pointed out a large reduction in the sand bar at
the mouth of Stone Creek as an example of extreme
erOSIOn.
Reilly observed the relation between sand-bar
erosion, tributary flows, and pre-dam river flows. He
observed bank calving during a 3-4 foot rise in the river
in 1956 that resulted from storm runoff. At Tapeats
Creek (mile 133.8-R) in 1962, Reilly watched as the

river eroded the sand bar below the rapid. He saw large
channels cut through sand bars during storm runoff in
1953. These incidents were mentioned primarily
because Reilly considered sand bar erosion a hazard to
sleeping boatmen, not because he was concerned that
sand bars were diminishing.
Cross II, who ran the river frequently in the years
after closure of Glen Canyon Dam, described the slow,
progressive loss of sand bars in Marble Canyon
through the 1960s. He believed that wind erosion and
human impacts, not large clear-water releases such as
the 1965 high flows, were the dominant reasons for
sand bar erosion from 1963, through about the mid-
1970s. He used the separation bar at Soap Creek Rapid
(mile 11.3) as an example of a campsite that, from his
memory, just gradually blew away.
Rigg thought that the sand-bar erosion
downstream from Nankoweap Creek was probably the
greatest of any place in Grand Canyon. What formerly
was a sand-lined channel is now a reach lined with
gravel bars. We had previously recognized the extent
of sand-bar erosion in this reach (Webb, 1996).

Channel Bars

The Old Timers were impressed with changes in
three debris-bar-controlled rapids. The Rock Garden at
Crystal Rapid (mile 98.4) formed as a consequence of
the 1966 debris flow and subsequent reworking by the
Colorado River. No pre-dam river runners (or their
photographs) noted the presence of a debris bar below
Crystal Rapid before 1966. Shoemaker, Rigg, and
Nichols felt that the debris bars at the mouth of the
Little Colorado River, and Vaseys Paradise (mile 31.8-
R) had aggraded significantly, although they admitted
that the perceived changes could, at least partly be
attributed to differences in water level. Pre-dam river
runners, particularly Reilly, ran left of the island at the

SPECIFIC CHANGES OBSERVED IN GRAND CANYON 17