CoastGIS'99: geomatics and coastal environment
the increase or decrease in depth. The coefficient of determination
expresses how accurately the data is described by the trend line. A
problem of this analysis is that a trend line assumes a continous trend
during the entire time period, which is not necessarily the case for the
investigated shoreface. Also, a minimum number of survey campaigns
must be available for a given grid cell to obtain a reliable result. The
spatial distribution of the regression parameters visualized within the
C9IS leads to interesting results.
Synthetic parameters
When some of the parameters describecl above are combined, a variety
of synthetic parameters can be generated. Resulting combination parameters can be superior to conventional parameters. For example, a combination of the gradients (correlation coefficient and average turnover)
promises a good description of the morphodynamic characteristics of
a certain area.
Conception of a morphodynamic zonation in the shoreface area
Conventionally morphological zones in the shoreface are delineated by
depth and/or occurring morphological forms. A grid database in the
GIS enables a more detailed zonation. Based on calculated parameters,
as described above, the shoreface can be divided into areas of different
morphodynamic activity and sediment dynamics. The morphodynamics
in each zone is described by several typical, quantified values, as described
in principle in table 2. The proposed morphodynamic zonation still needs
some improvements and refinements. Especially the selection, combination
and weighting of the parameters are still underway, but the first results
are promising a detailed zonation of the foreshore area. Different
morphodynamic zones happen to be corresponding quite well to the
distribution of morphological forms.
Table 2 - Proposal for a morphodynamic zonation of the shoreface of the East Frisian Islands
based on statistical parameters.
Zone
Depth
Characteristic
Turnover
In-or
Correlation Aclclitional
morphological
forms
decrease
of depth
per year
coefficient
r 2
parameters
Foreshore
0 - -4 m NN strand parallel flats
+ +
+ + to —
-
?
Upper shoreface
partly shoreface
(accumulative)
-4 - -8 m NN
connected ridges
+ +
+
-
?
Lower shoreface
(erosive)
-4 -- 8 m NN
p
f
0
?
Lower shoreface
-8 - -20 m NN partly large ridges
0
-
+
Flat seaground
< - 20 m NN
unstructured, flat
0
0
+ +
?
Typical values for these parameters have to be determined. Meaning of the symbols: ++ very large , + large, 0 almost zero,
- small, " very small.
230
the increase or decrease in depth. The coefficient of determination
expresses how accurately the data is described by the trend line. A
problem of this analysis is that a trend line assumes a continous trend
during the entire time period, which is not necessarily the case for the
investigated shoreface. Also, a minimum number of survey campaigns
must be available for a given grid cell to obtain a reliable result. The
spatial distribution of the regression parameters visualized within the
C9IS leads to interesting results.
Synthetic parameters
When some of the parameters describecl above are combined, a variety
of synthetic parameters can be generated. Resulting combination parameters can be superior to conventional parameters. For example, a combination of the gradients (correlation coefficient and average turnover)
promises a good description of the morphodynamic characteristics of
a certain area.
Conception of a morphodynamic zonation in the shoreface area
Conventionally morphological zones in the shoreface are delineated by
depth and/or occurring morphological forms. A grid database in the
GIS enables a more detailed zonation. Based on calculated parameters,
as described above, the shoreface can be divided into areas of different
morphodynamic activity and sediment dynamics. The morphodynamics
in each zone is described by several typical, quantified values, as described
in principle in table 2. The proposed morphodynamic zonation still needs
some improvements and refinements. Especially the selection, combination
and weighting of the parameters are still underway, but the first results
are promising a detailed zonation of the foreshore area. Different
morphodynamic zones happen to be corresponding quite well to the
distribution of morphological forms.
Table 2 - Proposal for a morphodynamic zonation of the shoreface of the East Frisian Islands
based on statistical parameters.
Zone
Depth
Characteristic
Turnover
In-or
Correlation Aclclitional
morphological
forms
decrease
of depth
per year
coefficient
r 2
parameters
Foreshore
0 - -4 m NN strand parallel flats
+ +
+ + to —
-
?
Upper shoreface
partly shoreface
(accumulative)
-4 - -8 m NN
connected ridges
+ +
+
-
?
Lower shoreface
(erosive)
-4 -- 8 m NN
p
f
0
?
Lower shoreface
-8 - -20 m NN partly large ridges
0
-
+
Flat seaground
< - 20 m NN
unstructured, flat
0
0
+ +
?
Typical values for these parameters have to be determined. Meaning of the symbols: ++ very large , + large, 0 almost zero,
- small, " very small.
230