CoastGIS'99: geomatics and coastal environment
A GIS application for the study
of the morphodynamics in the shoreface
area of the German Bight:
methods and problems
Peter Hüttemeyer
Lower Saxony State Agency for Ecology, Coastal Research Station, An der Mühle 5, 26548
Norderney, Germany - huttemeyer@gmx.de
Abstract
In the shoreface of the German Bight an increase of depth and a related
steepening of the profile has been observed over several decades. A
negative influence to coastal protection is expected. Extensive evaluations of sea survey data were started to understand the underlying morphological processes. The sea survey data are evaluated with a GIS and
found inaccurate for detailed morphological studies. Statistical method
for an evaluation of the data quality, morphodynamics and a concept
for a morphodynamic zonation of the shoreface based on statistical
parameters are presented. The results achieved with a GIS and the developed evaluation methods are more accurate and extensive than with
conventional methods.
Introduction
The German Bight coast mainly consists of sandy sediments and is
susceptible to the attacking forces of current and swell. In the shoreface
swell energy is absorbed and sand is transported. The transported sand
is part of the supply of the islands and the coast and contributes to
their conservation. In different local examinations of sea surveys an
increase of depth over time was observed, resulting in a long-term
steepening of the shoreface profde (Stephan et al., 1998; Verwaest. et al.,
1999). Because of the steepening, forces attacking beaches, dunes and
dykes are expected to increase. Furthermore, a reducing influence on
the transport of sand parallel to the coastline, which is important for
the preservation of the islands, is expected.
To study the steepening process and the morphodynamics in the shoreface area sea survey data of the German Bight collected during the last
50 years were examined with the use of GIS-software (several ESRI products)
and evaluation methods considering the special character of sea survey
data were developed. Used GIS methods, the problem with the quality
of the sea survey data, the importance of metadata and first results are
represented.
222
A GIS application for the study
of the morphodynamics in the shoreface
area of the German Bight:
methods and problems
Peter Hüttemeyer
Lower Saxony State Agency for Ecology, Coastal Research Station, An der Mühle 5, 26548
Norderney, Germany - huttemeyer@gmx.de
Abstract
In the shoreface of the German Bight an increase of depth and a related
steepening of the profile has been observed over several decades. A
negative influence to coastal protection is expected. Extensive evaluations of sea survey data were started to understand the underlying morphological processes. The sea survey data are evaluated with a GIS and
found inaccurate for detailed morphological studies. Statistical method
for an evaluation of the data quality, morphodynamics and a concept
for a morphodynamic zonation of the shoreface based on statistical
parameters are presented. The results achieved with a GIS and the developed evaluation methods are more accurate and extensive than with
conventional methods.
Introduction
The German Bight coast mainly consists of sandy sediments and is
susceptible to the attacking forces of current and swell. In the shoreface
swell energy is absorbed and sand is transported. The transported sand
is part of the supply of the islands and the coast and contributes to
their conservation. In different local examinations of sea surveys an
increase of depth over time was observed, resulting in a long-term
steepening of the shoreface profde (Stephan et al., 1998; Verwaest. et al.,
1999). Because of the steepening, forces attacking beaches, dunes and
dykes are expected to increase. Furthermore, a reducing influence on
the transport of sand parallel to the coastline, which is important for
the preservation of the islands, is expected.
To study the steepening process and the morphodynamics in the shoreface area sea survey data of the German Bight collected during the last
50 years were examined with the use of GIS-software (several ESRI products)
and evaluation methods considering the special character of sea survey
data were developed. Used GIS methods, the problem with the quality
of the sea survey data, the importance of metadata and first results are
represented.
222