scholarly journals Late Holocene channel pattern change from laterally stable to meandering caused by climate and land use changes

2018 ◽  
Author(s):  
Jasper H. J. Candel ◽  
Maarten G. Kleinhans ◽  
Bart Makaske ◽  
Wim Z. Hoek ◽  
Cindy Quik ◽  
...  
Keyword(s):  
Land Use ◽  
Middle Ages ◽  
Land Use Changes ◽  
River Channel ◽  
Osl Dating ◽  
Meandering Rivers ◽  
Channel Pattern ◽  
The Holocene ◽  
Late Middle Ages ◽  
Bankfull Discharge

Abstract. River channel patterns may alter due to changes in hydrological regime, related to changes in climate or land cover. Such changes are well documented for transitions between meandering and braiding rivers, whereas channel pattern changes between laterally stable and meandering rivers are poorly documented and understood. We identified a river that was laterally almost stable throughout the Holocene until the Late Middle Ages, after which large meanders formed at lateral migration rates of about 2 m yr−1. The lateral stability before the Late Middle Ages was proven using a combination of coring information, ground-penetrating radar (GPR), radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. Our objective of this work is to identify the possible causes for the meander initiation. We carried out a unique reconstruction of bankfull discharge as a function of time, based on channel dimensions that were reconstructed from the scroll bar sequence using coring information and GPR data, combined with chronological constraints from historical maps and OSL dating. Empirical channel and bar pattern models were used to determine the potential for meandering and to identify the causes of meander initiation. Several potential causes were investigated, varying from discharge regime changes to increased sediment input. Our investigation shows that bankfull discharge was two to five times higher during the meandering phase compared to the laterally stable phase. This increase likely reflects climate changes related to the Little Ice Age and land use changes in the catchment, in particular as a result of peat reclamation and exploitation. We hypothesize that many low-energy meandering rivers were laterally stable during most of the Holocene, reflecting relatively low peak discharges during a stable climate and with limited human impact. However, channel deposits associated with such stable phases are poorly preserved, due to recent increase in dynamics of such systems. Considering the importance of climate and land use changes on the river channel pattern, successful river restoration requires an integral approach that includes scenarios of climate and land use changes in the catchment.

scholarly journals Late Holocene channel pattern change from laterally stable to meandering – a palaeohydrological reconstruction

2018 ◽  
Vol 6 (3) ◽  
pp. 723-741 ◽  
Author(s):  
Jasper H. J. Candel ◽  
Maarten G. Kleinhans ◽  
Bart Makaske ◽  
Wim Z. Hoek ◽  
Cindy Quik ◽  
...  
Keyword(s):  
Middle Ages ◽  
Late Holocene ◽  
Low Energy ◽  
Osl Dating ◽  
Meandering Rivers ◽  
Channel Pattern ◽  
The Holocene ◽  
Late Middle Ages ◽  
Bankfull Discharge ◽  
Pattern Change

Abstract. River channel patterns may alter due to changes in hydrological regime related to changes in climate and/or land cover. Such changes are well documented for transitions between meandering and braiding rivers, whereas channel pattern changes between laterally stable and meandering rivers are poorly documented and understood. We hypothesize that many low-energy meandering rivers had relatively low peak discharges and were laterally stable during most of the Holocene, when climate was relatively stable and human impact was limited. Our objectives in this work are to identify a Late Holocene channel pattern change for the low-energy Overijsselse Vecht river, to develop and apply a novel methodology to reconstruct discharge as a function of time following a stochastic approach, and to relate this channel pattern change to reconstructed hydrological changes. We established that the Overijsselse Vecht was laterally virtually stable throughout the Holocene until the Late Middle Ages, after which large meanders formed at lateral migration rates of about 2 m yr−1. The lateral stability before the Late Middle Ages was constrained using a combination of coring information, ground-penetrating radar (GPR), radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. We quantified bankfull palaeodischarge as a function of time based on channel dimensions that were reconstructed from the scroll bar sequence and channel cut-offs using coring information and GPR data, combined with chronological constraints from historical maps and OSL dating. We found that the bankfull discharge was significantly greater during the meandering phase compared to the laterally stable phase. Empirical channel and bar pattern models showed that this increase can explain the channel pattern change. The bankfull discharge increase likely reflects climate changes related to the Little Ice Age and/or land use changes in the catchment, in particular as a result of peat reclamation and exploitation.

scholarly journals Disturbances Of The Holocene Lake-Bog Sediment Succession As Revealed By Pollen Record From Wietrzychowice (Southeastern Kujawy, Central Poland)

2015 ◽  
Vol 32 (2) ◽  
pp. 91-97
Author(s):  
Eva Břízová ◽  
Małgorzata Roman
Keyword(s):  
Middle Ages ◽  
Pollen Analysis ◽  
Pollen Record ◽  
Sediment Characteristics ◽  
Pollen Data ◽  
The Holocene ◽  
The Third ◽  
Late Middle Ages ◽  
Organic Sediments ◽  
Funnel Beaker Culture

Abstract Results of geological and pollen investigations of the lake-bog sediments from the section Wietrzychowice W5, located nearby the Neolithic Funnel Beaker Culture (FBC) megaliths, are presented. The pollen data reveal that sedimentation at Wietrzychowice has begun at the beginning of the Holocene (Preboreal). Pollen analysis was used to determine stratigraphy with regard to sediment characteristics. The pollen spectrum was divided into 8 LPAZes (1-7Xa, 7Xb) which were also, where possible, stratigraphically classified. Radiocarbon dating of 6 730 ± 90 BP (5 730–5 480 BC, MKL-702) at depth of 1.20 m confirmed the pollen analysis age estimation. Five settlement episodes were found in organic sediments in the upper part of the W5 core. The first was presumably during the Preboreal, the second in the early Atlantic, the third in the late Atlantic (probably Neolithic FBC), the fourth in the early Middle Ages and the last one in the late Middle Ages. The pollen analysis was useful to point irregularities in sediment succession. Such a situation made palaeoenvironmental interpretation difficult, but further research is still needed to enable an accurate reconstruction.

scholarly journals Maximum Holocene groundwater levels and associated extension of peat in the border zone of ‘Het Gooi’ (the Netherlands): a reconstruction based on the study of soil transects

2020 ◽  
Vol 99 ◽  
Author(s):  
Jan Sevink ◽  
Sander Koopman
Keyword(s):  
Hydraulic Conductivity ◽  
Sea Level ◽  
Middle Ages ◽  
Groundwater Level ◽  
Soil Characteristics ◽  
Border Zone ◽  
Maximum Extension ◽  
The Holocene ◽  
Late Middle Ages ◽  
Ridge System

Abstract The area ‘Het Gooi’ in the Netherlands is part of a Pleistocene ice-pushed ridge system that partially drowned during the Holocene upon sea level and associated groundwater rise. As a result, the ridge system was gradually encroached by peat. From the late Middle Ages onward, man reclaimed the peatlands surrounding Het Gooi, heavily reducing their extension and lowering the regional groundwater level by increasingly intensive drainage. Based on historical and archaeological arguments, several authors assume that the Holocene peat cover in the border zones of ‘Het Gooi’ formed the extension of large raised peat bogs that formed further to the west and east, respectively. They presume that in the late Middle Ages these extensions reached ‘upslope’ to a maximum altitude of 3 m + NAP (Dutch Ordnance Datum – approximating mean sea level). However, the original extension is difficult to reconstruct, as this peat has disappeared as a result of its exploitation and oxidation, if having been present at all. In this study, the maximum extension of the Holocene peat cover on the ice-pushed ridge system was reconstructed based on soil characteristics. Used soil characteristics concerned the presence of iron coatings around sand grains and the upper boundary of gleyic features, because these are indicators for the mean highest groundwater level (MHG). For peat to form, this MHG needs to be at or just above the ground surface for most of the year. Based on study of a number of soil transects, we reconstructed to what maximum altitude peat encroachment may have occurred. This ‘maximum extension’ can alternatively be described as the maximum altitude of the bottom of the peat onlapping the ridge system. In the western border zone, this peat cover was found to have reached to c. NAP or just above, near Hilversum. No indications were found for the occurrence of raised bogs. We conclude that the phreatic groundwater level in this zone was controlled by the sea level and associated lake levels (Naardermeer and Horstermeer), a dominant role being played by the shallow presence of Pleistocene formations with a high hydraulic conductivity. In the eastern border zone, altitudes were more variable and in places reached 2 m + NAP. Peat at this higher elevation probably formed under the influence of a higher phreatic groundwater level, induced by the presence of a clayey Eemian fill with low hydraulic conductivity in the adjacent glacial basin (the Eem valley). This study demonstrates the value of detailed soil transect studies for palaeogeographical reconstructions of the former Holocene peat cover in Pleistocene landscapes of NW Europe. It also provides independent data for validation of geohydrological models for such landscapes.

scholarly journals Dark Ages woodland recovery and the expansion of beech: a study of land use changes and related woodland dynamics during the Roman to Medieval transition period in northern Belgium

2020 ◽  
Vol 99 ◽  
Author(s):  
Koen Deforce ◽  
Jan Bastiaens ◽  
Philippe Crombé ◽  
Ewoud Deschepper ◽  
Kristof Haneca ◽  
...  
Keyword(s):  
Land Use ◽  
Middle Ages ◽  
Iron Age ◽  
Transition Period ◽  
Secondary Forest ◽  
Land Use Changes ◽  
Anthropogenic Factors ◽  
Small Scale ◽  
Ilex Aquifolium ◽  
Early Medieval Period

Abstract The results from analyses of botanical remains (pollen, wood, charcoal, seeds) from several archaeological features excavated in Kluizen (northern Belgium) are presented. The region was largely uninhabited until the Iron Age and Roman period when a rural settlement was established, resulting in small-scale woodland clearance. The site was subsequently abandoned from c. AD 270 till the High Middle Ages. The results of the archaeological and archaeobotanical analyses provide information on changes in land use and resulting dynamics of woodland cover and composition between c.600 BC and AD 1200, with a spatial and temporal resolution unrivalled in northern Belgium. Especially the long period of woodland regeneration following abandonment of the site around AD 270, covering the Late Roman and Early Medieval period, could be reconstructed in detail. Abandoned fields were first covered with pioneer woodland (Salix, Corylus and Betula), then Quercus-dominated secondary forest and finally a late-successional forest with Fagus sylvatica, Carpinus betulus and Ilex aquifolium, an evolution that took over 300 years. The results also indicate that the observed increase of Fagus during the Early Middle Ages, which was never an important element in the woodland vegetation in northern Belgium before, was related to climatic changes rather than anthropogenic factors.

scholarly journals Land use changes caused by bank erosion along the lower part of the Bosna river from 2001 to 2013

2014 ◽  
Vol 94 (4) ◽  
pp. 49-58 ◽  
Author(s):  
Radislav Tosic ◽  
Novica Lovric ◽  
Slavoljub Dragicevic
Keyword(s):  
Land Use ◽  
Temporal Dynamics ◽  
Land Use Changes ◽  
Arable Land ◽  
Bank Erosion ◽  
River Channel ◽  
Left Bank ◽  
Lateral Migration ◽  
Channel Migration ◽  
The Right

The river channel dynamics are result of the complex interaction between natural and human impact. In the presented study, we assessed spatial and temporal dynamics of Bosna river channel migration during 2001-2013 period using orthophoto images and GIS. We have identified that the total area of bank erosion during given period equaled 2.8695 km2, of which 1.2178 km2 were on the left bank and 1.6516 km2 on the right bank. The total area of bank accretion from 2001 to 2013 equaled 2.6841 km2, of which 1.2864 km2 was on the left bank and 1.3977 km2 on the right bank. The Bosna riverbed average movement in the period 2001-2013 was established in the amount of 60.7 m. During this period, the average lateral channel migration was 5.05 m per year. Lateral migration of the Bosna River has caused serious problems: disappearance of arable land, forests, pastures and meadows, economic loss due to the reduction of agricultural. Using statistical analysis of a land use structure changes along the lower part of Bosna River, we obtained the results which show significant lost in arable land. According to results, 42.3 ha of arable land, 171.9 ha forests and 31.8 ha pastures and meadows were lost during 2001-2013 period. The data presented here are significant for practical issues such as predicting channel migration rates for engineering and planning purposes, soil and water management.

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