Publikacje

Abstract:

Rivers of the Polish Carpathians incised deeply during the twentieth century, but detailed information about the timing and
amount of incision of their channels exists only for water-gauge cross sections. Applicability of photogrammetric extraction
of digital elevation models (DEMs) from archival aerial photos for reconstructing changes in vertical river position was
verified in the study of a 3-km reach of the Czarny Dunajec River. DEMs extracted from a few sets of archival aerial photos
from the years 1964–1994 together with recent orthophotos and DEMs were used in the analysis. Measurements taken in
river cross sections spaced at 100-m intervals indicated that on average the lowest point of the channel bed lowered between
1964 and 2009 by 1.74 ± 0.17 m, low-flow water surface by 1.57 ± 0.07 m, active river channel by 1.54 ± 0.12 m and the
belt of river migration by 1.03 ± 0.15 m. However, the change in vertical river position during the years 1964–2009 varied
greatly along the reach, with the elevation of low-flow water surface lowered by up to 3.61 ± 0.07 m in the upper part of the
reach and increased by up to 1.34 ± 0.07 m in its lower part. Combining the information about changes in vertical river posi-
tion and the width of river migration belt yielded data about the change in sediment volume in the reach, with an average
annual loss of sediment amounting to 256 ± 37 m 3 per 100-m channel segment. The study indicated that DEMs generated
from archival aerial photos can be a useful tool in analysing recent vertical channel changes outside water-gauge stations.

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Photogrammetric reconstruction of changes in vertical river position using archival aerial photos: case study of the Czarny Dunajec River, Polish Carpathians