Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland

Tonolla, Diego; Geilhausen, Martin; Döring, Michael

doi:10.1002/esp.5017

Please use this identifier to cite or link to this item: https://doi.org/10.21256/zhaw-20966

Publication type:	Article in scientific journal
Type of review:	Peer review (publication)
Title:	Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland
Authors:	Tonolla, Diego Geilhausen, Martin Döring, Michael
et. al:	No
DOI:	10.1002/esp.5017 10.21256/zhaw-20966
Published in:	Earth Surface Processes and Landforms
Volume(Issue):	46
Issue:	1
Page(s):	252
Pages to:	266
Issue Date:	10-Oct-2020
Publisher / Ed. Institution:	Wiley
ISSN:	0197-9337 1096-9837
Language:	English
Subjects:	Hydropower impacts; River and floodplain restoration; Altered flow and sediment regime; Aerial image analyses; Geomorphic changes; Active floodplain
Subject (DDC):	333: Economics of land and resources 551: Geology and hydrology
Abstract:	Hydropower alteration of the natural flow and sediment regime can severely degrade hydromorphology, thereby threatening biodiversity and overall ecosystem processes of rivers and their floodplains. Using sequences of aerial images, we quantified seven decades (1938/1942–2013) of spatiotemporal changes in channel and floodplain morphology, as well as changes in the physical habitats, of three floodplain river reaches of the Swiss pre‐Alps, two hydropower‐regulated and one near‐natural. In the Sarine River floodplain, within the first decades of hydropower impairment, the magnitude and frequency of flood events (Q2, Q10, Q30) decreased substantially. As a result, the area of pioneer floodplain habitats that depend on flood activity and sediment dynamic, such as bare sediments, decreased dramatically by approximately 95%. However, by 2013 vegetated areas had generally increased in comparison to the pre‐regulation period in 1943, indicating general vegetative colonization. Between 1943 and 2013, the active channel underwent essential narrowing (up to 62% width reduction in the residual flow reach) and habitat turnover rates were very low (5% of the total floodplain area changed habitat type five to six times). In contrast, from the 1950s onwards, the near‐natural floodplain of the Sense River experienced recurrent narrowing and widening, and frequent changes between bare and vegetated areas, reflecting the shifting habitat mosaic concept typical for natural floodplains. In the three reaches investigated, we found that the active floodplain width and erosion of vegetated areas were primarily controlled by medium to large floods (Q10, Q30), which combined with reduced time intervals between ordinary floods ≥ Q2 most likely mobilized streambed sediments and limited the ability of vegetation to establish itself on bare gravel bars within the parafluvial zone. These findings can contribute to restoration action plans such as controlled flooding and sediment replenishments in the Sarine and other floodplain rivers of the Alps.
Further description:	This is the peer reviewed version which has been published in final form at https://doi.org/10.1002/esp.5017 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
URI:	https://digitalcollection.zhaw.ch/handle/11475/20966
Fulltext version:	Accepted version
License (according to publishing contract):	Licence according to publishing contract
Restricted until:	2021-10-11
Departement:	Life Sciences and Facility Management
Organisational Unit:	Institute of Natural Resource Sciences (IUNR)
Published as part of the ZHAW project:	Nachhaltiges Auenmanagement und Wasserkraft - HyApp NRP70
Appears in collections:	Publikationen Life Sciences und Facility Management

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Tonolla, D., Geilhausen, M., & Döring, M. (2020). Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland. Earth Surface Processes and Landforms, 46(1), 252–266. https://doi.org/10.1002/esp.5017

Tonolla, D., Geilhausen, M. and Döring, M. (2020) ‘Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland’, Earth Surface Processes and Landforms, 46(1), pp. 252–266. Available at: https://doi.org/10.1002/esp.5017.

D. Tonolla, M. Geilhausen, and M. Döring, “Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland,” Earth Surface Processes and Landforms, vol. 46, no. 1, pp. 252–266, Oct. 2020, doi: 10.1002/esp.5017.

TONOLLA, Diego, Martin GEILHAUSEN und Michael DÖRING, 2020. Seven decades of hydrogeomorphological changes in a near‐natural (Sense River) and a hydropower‐regulated (Sarine River) pre‐Alpine river floodplain in Western Switzerland. Earth Surface Processes and Landforms. 10 Oktober 2020. Bd. 46, Nr. 1, S. 252–266. DOI 10.1002/esp.5017

Tonolla, Diego, Martin Geilhausen, and Michael Döring. 2020. “Seven Decades of Hydrogeomorphological Changes in a near‐Natural (Sense River) and a Hydropower‐Regulated (Sarine River) Pre‐Alpine River Floodplain in Western Switzerland.” Earth Surface Processes and Landforms 46 (1): 252–66. https://doi.org/10.1002/esp.5017.

Tonolla, Diego, et al. “Seven Decades of Hydrogeomorphological Changes in a near‐Natural (Sense River) and a Hydropower‐Regulated (Sarine River) Pre‐Alpine River Floodplain in Western Switzerland.” Earth Surface Processes and Landforms, vol. 46, no. 1, Oct. 2020, pp. 252–66, https://doi.org/10.1002/esp.5017.