Response of lateral channel dynamics of a lowland meandering river to engineering-derived adjustments - an example of the Morava River (Czech Republic)

• Autoři: ONDRUCH Jakub; MÁČKA Zdeněk
• Rok publikování: 2015
• Druh: Článek v odborném periodiku
• Časopis / Zdroj: Open Geosciences
• Fakulta / Pracoviště MU: Přírodovědecká fakulta
• www: http://www.degruyter.com/view/j/geo.2015.7.issue-1/geo-2015-0047/geo-2015-0047.xml?format=INT
• Doi: http://dx.doi.org/10.1515/geo-2015-0047
• Obor: Zemský magnetismus, geodesie, geografie
• Klíčová slova: meandering rivers; channel planform changes; river regulation; GIS; Morava River
• Popis: Freely meandering (quasi)natural reaches of lowland rivers represent a rare phenomenon in Central Eu- rope. Increasing attention is currently being paid to the dynamics of quasi-natural (articially inuenced) mean- dering rivers as this attention represents the basic pre- requisite for the development of appropriate restoration strategies on regulated rivers. This study focused on a 5.5 km long reach of the Morava River in the StrážnickĂ© Po- moravĂ­ region, Czech Republic that is characterised by quasi-natural evolution after substantial engineering ad- justments were made in the rst decades of the twentieth century. Based on Geographic Information Systems (GIS) analysis of aerial photographs, the spatio-temporal dy- namics of bank erosion and accretion rates were quantita- tively described and variables that control channel migra- tion rates were identied. High rates of lateral shifts were localised in high sinuosity segments (sinuosity 1.17-2.37), whereas segments with very low rates were straight or formed into slightly curved bends (sinuosity 1.05-1.18). As a key factor, engineering works that inuenced local river bed slope and induced a dramatic increase in bank erosion rates were identied. River engineering works induced a dramatic increase in bank erosion rate (2.19 m/year for 1938-53 and 1.47 m/year for 1953-63). An interval of ap- proximately 25 years was needed before the erosion rates dropped back to values documented before river regula- tion (0.35-1.09 m/year for 1841-1938). Other important con- trolling variables included radius of curvature, frequency and magnitude of oods and, locally, river bank material properties and oodplain land cover.

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