Original scientific paper

Geomorphological evolution of river valleys and river mouths on the Istrian peninsula

Čedomir Benac orcid.org/0000-0002-2961-5485 ; Faculty of Civil Engineering, Unniversity of Rijeka, Rijeka, Croatia
Josip Rubinić ; Faculty of Civil Engineering, Unniversity of Rijeka, Rijeka, Croatia
Maja Radišić ; Faculty of Civil Engineering, Unniversity of Rijeka, Rijeka, Croatia

Abstract

The paper analyses geomorphological changes in the floodplains and river mouths of the Dragonja, Mirna and Raša which flow through the Istrian peninsula. These changes were determined by comparing the historical and contemporary maps. The oldest maps of the Raša river valley date back to the second half of the 18th century, whereas the maps depicting the Dragonja and Mirna areas originate from the first half of the 19th century. The comparison showed a markedly large progression of the Raša river mouth, minor changes in the Mirna river mouth and no visible changes in the Dragonja river mouth due to the salt works establishment. Sediment production is caused by marl and flysch erosion in the upstream areas of the river basins, the majority of which arrives at the river mouth in the form of a suspension. The river regulation works prevented further flooding in the Mirna and Raša river valleys, including in the Dragonja river valley in the 1950s. Following this, changes can be seen only in the reduced depth of the sea bottom around the river mouth. A reduction in sediment transport was evident already by the end of the 20th century due to reduced land cultivation and forest spreading.

Keywords

erosion; sediment transport; deposition; river mouth; estuary; Istria

Hrčak ID:

183726

URI

https://hrcak.srce.hr/183726

Publication date:

29.6.2017.

Article data in other languages: croatian

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