Environmental Engineering Reference
In-Depth Information
Chapter 7
Overall Conclusion and Discussion
7.1 Overall Conclusion
The methodology applied in this research aimed to find a scientific relationship
between flood events, climate change, and land use change from the past until the
present. The objectives of the dissertation were to develop and apply methods for
flood hazard assessment, to detect land use change as well as climatological and
hydrological trend analysis in time series. As an overall conclusion, this chapter
attempts to review and discuss the research objectives based on all achieved
results:
Objective (a):
• As for the first assumption, interpolation methods that often assume data points
in original DEM are correct (exact), but it can be assumed that they are subject
to error (generally of a known or estimated extent). This means the interpolation
technique is not only for creating DEM from contour lines or observed data
points, but also for correcting DEMs that contain errors, such as sink errors.
Therefore, the main purpose was to correct the original DEM, find the possible
errors, and to address the best interpolation techniques in order to erase these
errors. To compare the accuracy of the original DEM and modeled DEMs,
the stream network was derived for each interpolated surface and the original
DEM. By visualization analysis of all achieved results, it seems that IDW,
Spline, Circular, Exponential, and Stable produced the poorest results mainly in
the upstream, where a small part of the main channel is missing. The results
obtained from Topo to Raster, Gaussian, and Spherical-derived drainage net-
works coincided better with the reference stream network. Still, there is some
discrepancy in the modeled network in some parts where the river follows a
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