Jökull - 01.01.2009, Blaðsíða 26

A. A. Beylich
Table 3. Annual runoff events and denudation in Latnjavagge. – Ársúrkoma, aurburður og efnahvarfarof í
Latnjavagge.
Year Runoff Mean Yield of Mean Yield of Chemical
weighted suspended weighted dissolved denudation
SSC solids TDS solids
[mm] [mm l−1] [t km−2] [mm l−1] [t km−2] [t km−2]
2000 754 3.3 2.6 11.9 9.0
2001 748 3.0 2.3 12.2 9.1
2002 648 3.1 2.1 12.0 7.8
2003 663 3.2 2.2 12.2 8.1
2004 798 3.2 2.6 12.0 9.6
2005 731 3. 2.7 12.0 8.8
2006 742 3.1 2.3 12.0 8.9
2007 650 3.2 2.1 12.0 8.1
Annual mean
2002 – 2007 324 0.8 0.25 25.2 8.2 3.1
Table 4. Peak runoff events and fluvial suspended sediment transport in Hrafndalur. – Leysing og aurburður í
Hrafndal.
Year Precipitation Runoff Mean Annual Number Sediment Percent of
weighted suspended of days yield of annual
SSC sediment with Q > during suspended
yield 40 mm d!1 these days sediment
[mm] [mm] [mg l!1] [t km!2] [t km!2] yield
2002 2281 1779 17.2 30.6 8 23.9 78
2003 1666 1283 14.0 18.0 5 14.2 79
2004 1390 1112 10.2 11.4 4 9.3 82
2005 1626 1285 10.8 13.8 4 11.0 80
2006 1869 1458 15.8 23.0 8 17.7 77
2007 1483 1149 112.2 14.0 5 11.3 81
Annual mean
2002 – 2007 1719 1344 13.4 18.5 5.7 14.6 80
iment yield was transported during these days (Table
4). Significantly increased suspended sediment con-
centrations as well as high bed load-transport rates
are connected to debris flows triggered by heavy rain-
fall and transporting material into main channels and
to slope wash processes. High mechanical weather-
ing rates in combination with limited vegetation cover
on rhyolitic bedrock in the Hrafndalur catchment are
key factors for the high sediment delivery rates from
the slope systems during days with heavy rainfall and
connected rainfall-generated runoff peaks over 40 mm
d−1(Beylich and Kneisel, 2009).
In the Kidisjoki catchment, snowmelt in spring re-
leases a large amount of water within a short time,
with 30% of the melting snow being discharged dur-
ing the first few days. The remainder is released
within 4–6 weeks (Beylich et al., 2006b). Due to
frozen ground and sheets of ice at the bottom of
26 JÖKULL No. 59