Jökull - 01.12.1999, Blaðsíða 54

MAXiMUM WATER SURFACE
NET DEPOSITION
PRE-FLOOD TERRACE
POST-FLOOD TERRACE
NET EROSION
TRANSECT3
PRE-FLOOD
ACTIVE CHANNEL
RIVFR
0 200 400 600 800 1000 1200
(m)
X PROFILE 1
(m)
Figure 4d. Pre- and post-jökulhlaup channel cross profiles 2 and 3 and post-jökulhlaup profile 1. In this zone
the flood created a much wider, shallower and less sinuous channel, while locally the bed was lowered by up to
6 m, leaving suites of marginal erosional terraces. — Þversnið 2 og 3 tekin fyrir og eftir hlaup ásamt þversniði
1 sem tekið var eftir hlaup. A þessu svæði skóp hlaupið mun breiðari, grynnri og beinni farveg en það hafði
áður. Sums staðar lœkkaði árbotninn um allt að 6 mog þrep mynduðust í árbakkana.
often created local slackwater conditions suitable for
deposition of late rising stage and waning stage sands
and gravels (Russell and Knudsen, 1999) (Figure 7).
The main channel bar also supported large numbers of
classic obstacle marks characterised by proximal sub-
strate erosion and distal deposition (Figures 2 and 3b)
(Russell, 1993).
Data used in the calculation of discharges for
channel cross-sections 1-3 are provided in Tables 1-
3 respectively. These data include the proportion of
52 JÖKULL, No. 47