The Role of Hydrologic Alteration and Riparian Vegetation Dynamics in Channel Evolution along the Lower Minnesota River

Lenhart, Christian; Titov, M.; Ulrich, J.; Nieber, John L.; Suppes, Britta

doi:10.13031/2013.42686

Cited by 21 publications

(18 citation statements)

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“…The model is developed for alluvial channels, which self-adjust their width, depth, and slope in response to the magnitude and frequency of geomorphically effective flows, changes in sediment supply and caliber relative to sediment transport capacity, and the efficiency of riparian vegetation to stabilize channel banks and floodplains within different climatic settings [Lane, 1955;Wolman and Gerson, 1978;Wolman and Miller, 1960;Yu and Wolman, 1987;Lenhart et al, 2013].…”

Section: Modelmentioning

confidence: 99%

“…However, the rivers are incising through semi to wellconsolidated glacio-fluvial sediments and maintain continuous and relatively thick active layers of alluvium on the bed. Rapid erosion of stream banks and bluffs from channel adjustment within these two systems as a result of the recent shift in hydrology has led to an increase in sediment supplied downstream, which in turn has resulted in significant channel adjustment, floodplain aggradation, and water quality impairment Water Resources Research 10.1002/2016WR020277 on the main stem Minnesota River and further points downstream Markus, 2011;Lenhart et al, 2013].…”

Section: Empirical Analysis Of Hydrologic and Geomorphic Change In MImentioning

confidence: 99%

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Changes in floodplain inundation under nonstationary hydrology for an adjustable, alluvial river channel

Call

Belmont

Schmidt

et al. 2017

Water Resources Research

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Predicting the frequency and aerial extent of flooding in river valleys is essential for infrastructure design, environmental management, and risk assessment. Conventional flood prediction relies on assumptions of stationary flood distributions and static channel geometries. However, nonstationary flow regimes are increasingly observed and changes in flow and/or sediment supply are known to alter the geometry and flood conveyance of alluvial channels. Systematic changes in flows and/or channel geometry may amplify or attenuate the frequency and/or extent of flood inundation in unexpected ways. We present a stochastic, reduced complexity model to investigate such dynamics. The model routes a series of annual peak discharges through a simplified reach‐averaged channel‐floodplain cross section. Channel width, depth, and slope are permitted to adjust annually by a user‐specified fraction toward equilibrium geometries predicted based on each year's peak discharge and sediment supply. Modeled channel adjustments are compared with empirical observations for two rivers in Minnesota, USA that have experienced multiple large floods over the past 6 years. The model is then run using six hypothetical scenarios simulating nonstationary flow regimes with temporal adjustments in the mean and/or variance of the governing peak‐flow distributions. Each scenario is run repeatedly while varying parameters that control the amount of fractional adjustment that channel geometries can make annually. Results indicate that the intra‐annual mean horizontal width of floodplain inundation primarily depends on the governing peak‐flow distribution's coefficient of variation, but the intra‐annual frequency of floodplain inundation (i.e., the fraction of modeled years with inundation) primarily depends on the amount of channel adjustment permitted annually.

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Section: Modelmentioning

confidence: 99%

Section: Empirical Analysis Of Hydrologic and Geomorphic Change In MImentioning

confidence: 99%

Changes in floodplain inundation under nonstationary hydrology for an adjustable, alluvial river channel

Call

Belmont

Schmidt

et al. 2017

Water Resources Research

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“…Lauer et al (2017) have reported that the Minnesota River and its major tributaries have been subject to widening at an average rate of 0.62% yr À1 (relative to the average width between 2000 and 2009) since the 1930s. Similarly, Lenhart et al (2013) reported that rapid widening of the main stem of the Minnesota River began later than 1966, which is after an extreme flood event of 1965 (Strub, 1965;Novotny and Stefan, 2007). Some studies have suggested that the major source of sediment has shifted from upland to near-channel, primarily due to this rapid channel widening (Belmont et al, 2011;Schottler et al, 2014).…”

Section: Methodsmentioning

confidence: 98%

“…An assessment of the impact of hydrological regime shift on bankfull channel change is another potential application of the model, because of its use of the flow duration curve. Many previous studies have reported or studied changes in the bankfull geometry of meandering streams triggered by increased stream flow (Bradley and Smith, 1984;Simon, 1989;Simon and Rinaldi, 2000;Phillips et al, 2005;Lenhart et al, 2013;Lauer et al, 2017). Moreover, the effectiveness of moderately high flows with higher recurrence (rather than extreme flows) on morphological work has been recognized in classical studies (e.g., Wolman and Miller, 1960;Benson and Thomas, 1966).…”

Section: Introductionmentioning

confidence: 99%

Adjustment of self‐formed bankfull channel geometry of meandering rivers: modelling study

Naito

Parker

2020

Earth Surf Processes Landf

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We consider the evolution of the hydraulic geometry of sand-bed meandering rivers. We study the difference between the timescale of longitudinal river profile adjustment and that of channel width and depth adjustment. We also study the effect of hydrological regime alteration on the evolution of bankfull channel geometry. To achieve this, a previously developed model for the spatiotemporal co-evolution of bankfull channel characteristics, including bankfull discharge, bankfull width, bankfull depth and down-channel bed slope, is used. In our modelling framework, flow variability is considered in terms of a specified flow duration curve. Taking advantage of this unique feature, we identify the flow range responsible for long-term bankfull channel change within the specified flow duration curve. That is, the relative importance of extremely high short-duration flows compared to moderately high longer duration flows is examined. The Minnesota River, MN, USA, an actively meandering sand-bed stream, is selected for a case study. The longitudinal profile of the study reach has been in adjustment toward equilibrium since the end of the last glaciation, while its bankfull cross-section is rapidly widening due to hydrological regime change in the last several decades. We use the model to demonstrate that the timescale for longitudinal channel profile adjustment is much greater than the timescale for cross-sectional profile adjustment due to a lateral channel shift. We also show that hydrological regime shift is responsible for the recent rapid widening of the Minnesota River. Our analysis suggests that increases in the 5-25% exceedance flows play a more significant role in recent bankfull channel enlargement of the Minnesota River than increase in either the 0.1% exceedance flow or the 90% exceedance flow.

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“…The MRB drains approximately 43,400 km 2 of south-central Minnesota, South Dakota, and Iowa, USA ( Figure 1). The Minnesota River itself is disproportionately small (~100 m wide; Lauer et al, 2017) compared to its wide valley (up to 2 km wide; Lenhart et al, 2013) carved by outflows from glacial Lake Agassiz near the end of the last glaciation (Clayton & Moran, 1982;Matsch, 1983). Incision on the mainstem Minnesota River created knickpoints that have propagated upstream on all major tributaries, leading to deeply incised lower tributary valleys in an otherwise relatively flat postglacial landscape (Belmont, 2011;Gran et al, 2009Gran et al, , 2013.…”

Section: Mrb Environmental Observatorymentioning

confidence: 99%

The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin

Gran

Dolph

Baker

et al. 2019

Water Resources Research

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Observatory‐scale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundation‐funded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed Landscapes‐Critical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in south‐central Minnesota, USA, a 43,400‐km2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change, allowing for transdisciplinary research into the complex cascade of environmental changes that occur due to hydrology and land use alterations from intensive agricultural management and climate change. Data sets collected include water chemistry and biogeochemical data, geochemical fingerprinting of major sediment sources, high‐resolution monitoring of river bluff erosion, and repeat channel cross‐sectional and bathymetry data following major floods. The data collection efforts led to development of a series of integrative reduced complexity models that provide deeper insight into how water, sediment, and nutrients route and transform through a large channel network and respond to change. These models represent the culmination of efforts to integrate interdisciplinary data sets and science to gain new insights into watershed‐scale processes in order to advance management and decision making. The purpose of this paper is to present a synthesis of the data sets and models, disseminate them to the community for further research, and identify mechanisms used to expand the temporal and spatial extent of short‐term observatory‐scale data collection efforts.

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The Role of Hydrologic Alteration and Riparian Vegetation Dynamics in Channel Evolution along the Lower Minnesota River

Cited by 21 publications

References 0 publications

Changes in floodplain inundation under nonstationary hydrology for an adjustable, alluvial river channel

Changes in floodplain inundation under nonstationary hydrology for an adjustable, alluvial river channel

Adjustment of self‐formed bankfull channel geometry of meandering rivers: modelling study

The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin

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