Anthropogenic drivers for exceptionally large meander formation during the Late Holocene

Cindy Quik,Maurice Paulissen,Bart Makaske,Jakob Wallinga,Roy Van Beek,Menno Verplak,Gilbert J Maas,Jasper H.J Candel,Theo Spek

doi:10.1016/j.ancene.2020.100263

Cindy Quik, Maurice Paulissen + Show 7 more

Open Access

https://doi.org/10.1016/j.ancene.2020.100263

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Abstract

Large-amplitude meanders may form in low-energy rivers despite generally limited mobility in theses systems. Exceptionally large meanders which even extend beyond the valley sides have developed in the Overijsselse Vecht river (the Netherlands) between ca. 1400 CE (Common Era) and the early 1900s, when channelization occurred. Previous studies have attributed the enhanced lateral dynamics of this river to changes in river regime due to increased discharges, reflecting climate and/or land-use alterations in the catchment. This paper focuses on local aspects that may explain why exceptionally large meanders developed at specific sites. Through an integrated analysis based on archaeological, historical, and geomorphological data along with optically stimulated luminescence dating, we investigated the relative impact of three direct and indirect anthropogenic causes for the local morphological change and enhanced lateral migration rates: (1) lack of strategies to manage fluvial erosion; (2) a strong increase in the number of farmsteads and related intensified local land use from the High Middle Ages onwards; and (3) (human-induced) drift-sand activity directly adjacent to the river bends, causing a change in bank stability. Combined, these factors led locally to meander amplitudes well beyond the valley sides. Lessons learned at this site are relevant for management and restoration of meandering rivers in similar settings elsewhere, particularly in meeting the need to estimate spatial demands of (restored) low-energy fluvial systems and manage bank erosion.

Highlights

IntroductionLow-energy meandering rivers often show relatively little lateral migration (Kuenen, 1944; Eekhout, 2014; Makaske et al, 2016; Candel, 2020) because of their low specific stream power (< 10 W mÀ2) (Nanson and Croke, 1992)
PeriodLate Palaeolithic Mesolithic period Neolithic period Bronze age Iron age Roman period Early Middle ages High Middle ages Late Middle ages Early Modern period Late Modern period Time frame12,500 – 8800 BCE 8800 – 4900 BCE 4900 – 2000 BCE 2000 – 800 BCE 800 – 12 BCE 12 BCE – 450 CE 450 – 1000 CE 1000 – 1250 CE 1250 – 1500 CE 1500 – 1800 CE 1800 – 1900 CELow-energy meandering rivers often show relatively little lateral migration (Kuenen, 1944; Eekhout, 2014; Makaske et al, 2016; Candel, 2020) because of their low specific stream power (< 10 W mÀ2) (Nanson and Croke, 1992)
Meanders with high amplitude may occur in low-energy rivers, with relatively high lateral migration rates compared to other reaches of the same river (e.g. Hooke, 2007)

Summary

Introduction

Low-energy meandering rivers often show relatively little lateral migration (Kuenen, 1944; Eekhout, 2014; Makaske et al, 2016; Candel, 2020) because of their low specific stream power (< 10 W mÀ2) (Nanson and Croke, 1992). Meanders with high amplitude may occur in low-energy rivers, with relatively high lateral migration rates compared to other reaches of the same river The lateral migration rates of rivers strongly depend on local bank strength (Schumm, 1960; Hickin and Nanson, 1984; Ferguson, 1987; Nicoll and Hickin, 2010). Hudson and Kesel (2000) compared sections of the Mississippi river and showed that the lowest lateral migration rates occurred in sections where erosionresistant deposits were present (e.g. clay plugs). The potential direct and indirect role of humans in destabilising river banks locally has received little attention in literature, and is the main topic of this paper

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