Epsilon Archive for Student Projects

Abstract

Headwater streams are affected by anthropogenic impacts at multiple scales.
One aspect of human impact is sediment transport associated to the
abundance of stream structures as large woody debris and the composition
of the riparian zone from forest to agricultural landscapes.
Riparian buffer zones and stream structures like dead wood are considered
as generally important structures for protection against an increasing
amount of sediment particles in the water. Hence, in this study these
structures were quantified in thirty different stream segments on land and in
the water.
To measure the transport of sediment Whitlock-Vibert boxes were used in
three different types of landscapes; forest, transition and fields. The boxes
were left in the stream segments for three months, the taken up and dried
and weighed. The results showed that the transition-land in Frösvidalsån
had the highest sediment transport. The second highest transport of
sediment was in Blackstaån at the fields. A factor in common for both these
stream sections was that their naturally meandering shape had been
straightened. That indicates that straightened water streams attain a higher
degree of sediment transport. One contributory cause to the higher sediment
transport is the increasing velocity of the water stream.
To see if large woody debris could have a connection to the sediment
transport a correlations test was made. The test showed that the connection
was weak. In a second test the basal area of the riparian zones and the
sediment transport was compared to each other in the correlations test, the
results showed that the connection was week. In a third correlation test the
basal area of the riparian zones was compared to dead wood, also that test
showed a weak connection. In the last test the basal area of riparian zones
and large woody debris was compared and the test showed a weak
connection.