Modelling differential catchment response to environmental change

Coulthard, Tom; Lewin, John; Macklin, Mark G.

doi:10.1016/j.geomorph.2005.01.008

Cited by 138 publications

(136 citation statements)

References 32 publications

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“…The cross-section surveys suggested that, over the period December 2001 to March 2004, the upper part of the study reach was aggradational, with a reach-and width-averaged mean rise in bed levels of 0·22 ± 0·021 m, and this fits with much longer timescale simulations of this reach which also suggest aggradation (Coulthard et al, 2005). (Figure 2).…”

Section: Resultsmentioning

confidence: 54%

Interactions between sediment delivery, channel change, climate change and flood risk in a temperate upland environment

Lane¹,

Tayefi²,

Reid³

et al. 2006

Earth Surf Processes Landf

213

183

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This paper uses numerical simulation of flood inundation based on a coupled one-dimensionaltwo-dimensional treatment to explore the impacts upon flood extent of both long-term climate changes, predicted to the 2050s and 2080s, and short-term river channel changes in response to sediment delivery, for a temperate upland gravel-bed river. Results show that 16 months of measured in-channel sedimentation in an upland gravel-bed river cause about half of the increase in inundation extent that was simulated to arise from climate change. Consideration of the joint impacts of climate change and sedimentation emphasized the nonlinear nature of system response, and the possibly severe and synergistic effects that come from combined direct effects of climate change and sediment delivery. Such effects are likely to be exacerbated further as a result of the impacts of climate change upon coarse sediment delivery. In generic terms, these processes are commonly overlooked in flood risk mapping exercises and are likely to be important in any river system where there are high rates of sediment delivery and long-term transfer of sediment to floodplain storage (i.e. alluviation involving active channel aggradation and migration). Similarly, attempts to reduce channel migration through river bank stabilization are likely to exacerbate this process as without bank erosion, channel capacity cannot be maintained. Finally, many flood risk mapping studies rely upon calibration based upon combining contemporary bed surveys with historical flood outlines, and this will lead to underestimation of the magnitude and frequency of floodplain inundation in an aggrading system for a flood of a given magnitude.

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Section: Resultsmentioning

confidence: 54%

Interactions between sediment delivery, channel change, climate change and flood risk in a temperate upland environment

Lane¹,

Tayefi²,

Reid³

et al. 2006

Earth Surf Processes Landf

213

183

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“…Terraces have formed in all global regions and are commonly studied to understand how rivers have responded to the combined effects of changes in external controls including climate, tectonics, and sea level (Merritts et al, 1994;Macklin et al, 2002;Bridgland and Westaway, 2008) and in internal controls, such as catchment morphology (Coulthard et al, 2005) and reach-specific conditions (Houben, 2003).…”

Section: Introductionmentioning

confidence: 99%

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

et al. 2015

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Alluvial terraces provide a record of aggradation and incision and are studied to understand river response to changes in climate, tectonic activity, sea level, and factors internal to the river system. Terraces form in all climatic regions and in a range of geomorphic settings; however, relatively few studies have been undertaken in tectonically stable settings in the tropics. The preservation of alluvial terraces in a valley is driven by lateral channel adjustments, vertical incision, aggradation, and channel stability, processes that can be further understood through examining catchment force-resistance frameworks. This study maps and classifies terraces using soil type, surface elevation, sedimentology, and optically stimulated luminescence dating across five tropical catchments in northeast Queensland, Australia. This allowed for the identification of two terraces across the study catchments (T1, T2).The T1 terrace was abandoned ~13.9 ka with its subsequent removal occurring until ~7.4 ka. Abandonment of the T2 terrace occurred ~4.9 ka with removal occurring until ~1.2 ka. Differences in the spatial preservation of these terraces were described using an index of terrace preservation (TPI). Assessments of terrace remnant configuration highlighted three main types of terraces: paired, unpaired, and disconnected, indicating the importance of different processes driving preservation.Regional-scale variability in TPI was not strongly correlated with catchment-scale surrogate variables for drivers of terrace erosion and resistance. However, catchmentspecific relationships between TPI and erosion-resistance variables were evident and are used here to explain the dominant processes driving preservation in these tropical settings. This study provides an important insight into terrace preservation in the tectonically stable, humid tropics and provides a framework for future research linking the timing of fluvial response to palaeoclimate change. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT IntroductionAlluvial terraces are topographic landforms that result from floodplain abandonment when a river incises, therefore providing records of river aggradation and incision (Leopold et al., 1964). Terraces have formed in all global regions and are commonly studied to understand how rivers have responded to the combined effects of changes in external controls including climate, tectonics, and sea level (Merritts et al., 1994;Macklin et al., 2002;Bridgland and Westaway, 2008) and in internal controls, such as catchment morphology (Coulthard et al., 2005) and reach-specific conditions (Houben, 2003).Terraces are generally identified in the landscape using a range of techniques including soil properties (see reviews in Birkeland, 1990;Huggett, 1998), topographic data (Pazzaglia and Gardner, 1993;Jones et al., 2007), aerial and satellite imagery (Litchfield and Berryman, 2005), with correlations further aided by sedimentology and dating (Stokes et al., 2012). The use of soil characteristics to classify terrace...

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“…As stated in the model description, CAESAR has successfully simulated landscape evolution in a range of environments Macklin, 2001, 2003;Coulthard et al, 2012a;Hancock et al, 2011;Welsh et al, 2009), but it is important to question whether the non-linear response of the model is simply a model by-product or a representation of actual basin dynamics? CAESAR has a long history of modelling the non-linear reaction of catchments from 1998 through to 2010 Coulthard et al, 1998Coulthard et al, , 2005Van De Wiel and Coulthard, 2010) and given that similar non-linear dynamics have been well documented in fluvial systems (Cudden and Hoey, 2003;Gomez and Phillips, 1999;Hooke, 2003;Stølum, 1998), we consider the simulation of non-linear sediment dynamics in CAESAR genuine. In addition, CAESAR is certainly not the only model to show non-linear sediment responses.…”

Section: Discussionmentioning

confidence: 99%

“…Their simulations showed that changes in discharge input and sediment storage (reflected in increased valley floor gradients) led to spikes in sediment associated with increased water inputs. Coulthard et al (2005) calculated individual sediment budgets for reaches of a medium sized drainage basin from basin simulations carried out over a 9000 yr period. Their research showed that during wetter periods (increased rainfall magnitudes) there was a dramatic increase in sediment yields and this was largely sourced from the lower, valley floor sections of the catchment.…”

Section: Introductionmentioning

confidence: 99%

Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

Coulthard

Wiel

2013

Earth Surf. Dynam.

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Abstract. Sediment yields from river basins are typically considered to be controlled by tectonic and climatic drivers. However, climate and tectonics can operate simultaneously and the impact of autogenic processes scrambling or shredding these inputs can make it hard to unpick the role of these drivers from the sedimentary record. Thus an understanding of the relative dominance of climate, tectonics or other processes in the output of sediment from a basin is vital. Here, we use a numerical landscape evolution model (CAESAR) to specifically examine the relative impact of climate change, tectonic uplift (instantaneous and gradual) and basin morphology on sediment yield. Unexpectedly, this shows how the sediment signal from significant rates of uplift (10 m instant or 25 mm a −1 ) may be lost due to internal storage effects within even a small basin. However, the signal from modest increases in rainfall magnitude (10-20 %) can be seen in increases in sediment yield. In addition, in larger basins, tectonic inputs can be significantly diluted by regular delivery from non-uplifted parts of the basin.

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Modelling differential catchment response to environmental change

Cited by 138 publications

References 32 publications

Interactions between sediment delivery, channel change, climate change and flood risk in a temperate upland environment

Interactions between sediment delivery, channel change, climate change and flood risk in a temperate upland environment

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

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