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sediment supply ( Q s ) and water discharge ( Q w ) with
either no or slight relative sea-level changes (e.g.
Kim & Jerolmack, 2008; Van Dijk et al ., 2009). These
shoreline fluctuations were caused by autocyclic
fluvial sediment storage and release associated
with changes in the fluvial planform pattern
between channelised flow and sheet flow (Fig. 1).
Sheet flow covers most of the delta top surface
and forces strong aggradation of the fluvial system
as hardly any sediment gets delivered to the shore-
line. Channelisation is initiated by focusing flow
in a narrow corridor on the delta top. As a result,
transport capacity increases due to increase in
both channel depth and flow velocity. Supplied
sediment, as well as eroded sediment from the
channel bed, is transported to the shoreline, thus
producing a strong pulse of shoreline regression.
Quantitative measurements of 1) the time frequency
of the autogenic process and 2) magnitude of the
autogenic shoreline fluctuation (i.e. shoreline
signature of the fluvial autogenic process) have
been reported (e.g. Kim & Jerolmack, 2008; Van Dijk
et al ., 2009).
experiments (10 to 18 hours of experimental run
time in XES 02 and 80 to 100 hours in XES 05),
during which the shorelines in both experiments
prograded 20 to 40 cm basinward (Fig.  2). The
overall lengths of both deltas were around 3 m but
XES 02 had a ~ 10 cm water depth and XES 05
had ~ 0.5 cm water depth in front of the deltas.
Autogenic sediment storage and release events
in the fluvial surface were observed twice during
the period that data were collected. During the
sediment storage events on the fluvial surface
associated with sheet/widespread flows, the shore-
line migration was reduced to a rate below the
long-term averaged progradation rate. However,
the shoreline rapidly advanced during release
events by strong channelisation. When the surface
is degraded and the shoreline progrades basinward
enough to decrease the topographic slope, a new
storage process is reinitiated. Autogenic processes
in XES 02 showed the shoreline migration with
high frequency and high magnitude fluctuations
(even with a deeper water depth at the delta front)
in comparison to the XES 05, which showed low
frequency and low magnitude shoreline fluctua-
tions (Fig. 2).
Three experiments conducted in the Eurotank
Flume facility at Utrecht University also exhibited
autocyclic incisions by channelised flow that
were then progressively backfilled by sediments
in the incised channels (Van Dijk et al ., 2009).
Two of the three experiments were conducted side
by side with the same Q s but different Q w values.
As a result, the sediment to water discharge ratio
in these two experiments varied between 0.002
(A004-1) and 0.003 (A004-2). For these experi-
ments the sediment mixture was composed of
grains with D = ~200 to 250 µm and the deltas were
built in a basin with a total size of 2.7 m × 2.7 m.
The decrease of Q w in A004-2 resulted in higher
topographic slopes than in the A004-1 experi-
ment, which reduced overall progradation of the
shoreline in A004-2. Roughly, A004-1 had a range
of delta-top slopes between 0.02 and 0.06 but
A004-2 had a range between 0.04 and 0.07. The
high Q w experiment shows more distinct shore-
line regression periods (total shoreline distance
travelled during each release event is longer) than
those periods shown in the low Q w experiment
(See Fig. 7 in van Dijk et al . (2009)), which would
be caused by more channelised incisions.
Reitz et al . (2010) reported a smaller-scale tank
experiment (3 m length × 1 m width × 1 m depth)
Autogenic shoreline fluctuation
Two sets of experimental data are presented in the
current analysis. One set is from the eXperimental
EarthScape (henceforth XES) facility at St. Anthony
Falls Laboratory, University of Minnesota and the
other is from the Eurotank Flume facility at Utrecht
University. The individual results have been
published (Kim & Jerolmack, 2008; Van Dijk et al .,
2009), so only a brief summary is given below.
Kim & Jerolmack (2008) used data from two
experiments in XES. The XES basin is 6 m long,
3 m wide and 1.5 m deep. A detailed description
of the XES facility can be found in Paola et al .
(2001). The experiment conducted in 2002 (XES
02) had roughly five times greater sediment dis-
charge than the second experiment conducted in
2005 (XES 05). However, both experiments had
roughly the same sediment to water supply ratio
( Q s / Q w ) at 0.01 in volume influx. Both experi-
ments used a sediment mixture with roughly 70%
quartz sand (D = 110 µm) and 30% coal sand
(bimodal D = 460 and 190 µm). The coal sediment
is much less dense than the quartz sediment and
thus works as a proxy for fine material. Sediment
supply and water discharge were kept constant
during the experiments. Data used for the analysis
were taken from the initial stages of the two
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