Browsing by Author "Paola, Chris"
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Item Bifurcation Experiments: Timeseries, Images, Topographic Scans, St. Anthony Falls Laboratory, 2016-2017(2019-05-17) Salter, Gerard L; Voller, Vaughan; Paola, Chris; salte040@umn.edu; Salter, Gerard LWe ran a set of five experiments at the St. Anthony Falls Laboratory in Minneapolis, Minnesota to study how the dynamics of a bifurcation are affected by the downstream boundary (deposition vs. bypass). These data accompany our publication in Earth Surface Dynamics.Item Delta Basin-2 Tidal Experiments (2016-2017)(2018-04-24) Lentsch, Nathan; Finotello, Alvise; Paola, Chris; lents045@d.umn.edu; Lentsch, Nathan; Saint Anthony Falls Laboratory - Sediment Transport GroupThese experiments were conducted in St. Anthony Fall Laboratory (SAFL) Delta Basin. This is a fixed based basin (5 m wide x 5 m long x 0.5 m deep) that is fed sediment and water from an input source to create model deltas. Sea-level adjustment via relative sea-level rise and tidal cycles is available in this facility and was in fact used for these experiments. This facility is able to collect data via an overhead DSLR camera (which made the time-lapse videos themselves) and a digital line scan camera capable of making digital elevation models with sub-millimeter accuracy.Item Delta Basin-2 Wave Experiments (2018-2019)(2019-11-12) Rodgers, Nicholas J; Paola, Chris; rodge231@umn.edu; Rodgers, Nicholas J; Saint Anthony Falls Laboratory - Sediment Transport GroupThese experiments were conducted in St. Anthony Fall Laboratory (SAFL) Delta Basin. This is a fixed based basin (5 m wide x 5 m long x 0.5 m deep) that is fed sediment and water from an input source to create model deltas. Sea-level adjustment via relative sea-level rise is available in this facility and was used for these experiments along with a floating wave generator. This facility is able to collect data via an overhead DSLR camera (which made the time-lapse videos themselves) and a digital line scan camera capable of making digital elevation models with sub-millimeter accuracy.Item Dynamic Tailings Basin Study: Final Report(St. Anthony Falls Laboratory, 1996-01) Whipple, Kelin X.; Parker, Gary; Paola, Chris; Mohrig, DavidThe Hibbing Taconite Company operates an iron mine and mill in northern Minnesota, USA The tailings produced by the mine are disposed in a tailings basin. The point of feed is the upstream end of one of the sub-basins within the tailings pond, the West Area #1. The tailings deposit forms an aggrading alluvial fan within each sub-basin. Projections of tailings deposition rates within the West Area # 1 indicate an imminent over-filling at the upper end of the basin. This premature filling, which threatens to reduce the lifetime of the tailings pond below design expectations, is the result of slopes in the upper part of the deposit which are steeper than anticipated at the time of basin design. st. Anthony Falls Laboratory, University of Minnesota, under contract from Barr Engineering, has undertaken a combined field, experimental, and theoretical study of the dynamics of tailings-basin sedimentation, with a particular focus on the physical controls (i.e., water discharge, sediment load, and sediment size distribution) on upper fan slope. This study has provided the tools necessary to evaluate the relative effectiveness of several tailings management schemes intended to alleviate the problem. The tools were developed in two stages. In Stage 1, the analysis was restricted to West Area #1 due to the availability of specific data pertaining to that area. The results for Stage 1 were based on the assumption that all future tailings would be stored in West Area #1. The assumption was made for illustrative purposes only. The results of the calculation allow, however, for inferences concerning the performance of the entire pond. In Stage 2, a numerical model was developed to describe filling of the entire basin. The model allows for the testing of a variety of schemes for tailings management.Item Experimental Study of Delta Erosion Due to Dam Removal [2007](2024-05-23) Cantelli, Alessandro; Parker, Gary; Paola, Chris; safl@umn.edu; SAFL, SAFL; National Center for Earth-Surface Dynamics (NCED)Cantelli, A., Paola, C. and Parker, G., 2004, Experiments on upstream-migrating erosional narrowing and widening of an incisional channel caused by dam removal, Water Resources Research, 40, W03304, doi:10.1029/2003/WR002940 The present paper reports on a laboratory investigation of the erosion of a deltaic front induced by the removal of a dam. We built a laboratory model of a dam, and observed both the sedimentation in the reservoir due to the downstream propagation of a delta front and the erosion of the delta front during dam removal, including measurement of channel morphology and flow field. Based on an analysis of bank erosion two principal erosive trends were detected: during the initial stage of erosion the width of each section quickly decreased to a minimum value, after which the section widened. Undistorted Froude similitude is used to scale the results up to field dimensions.Item Investigating the Roles of Wind Speed and Sediment Supply on Continental Shelf Formation(2017-04) Harrington, Stephen; Paola, ChrisContinental shelves represent an environment in which it is unclear whether the geometry has been affected by modern wave and wind interactions, or are the relict results of fluvial processes that have been drowned by rising sea levels since the Last Glacial Maximum. There are some modern examples of constructional shelves forming, but the sediment composition is primarily silty and muddy, not sandy. However, stratigraphic records show that sand is a major component of the continental shelf. This unique project investigated the use of silica sand to create a shelf with a steady-state transport system which is driven by waves and currents.Item Modelling Stream Braiding Over a Range of Scales(New Zealand Hydrological Society, 2001-01) Paola, ChrisModelling of fully developed braiding using conventional PDE techniques has been hindered by the difficulty of solving a nonlinear system of equations on a complex, constantly deforming domain. Simplified cellular models can reproduce many of the main features of braiding but their parameters are difficult to constrain. These two approaches are examples respectively of reductionism and synthesism, two approaches to modelling complex systems whose relative merits are being debated across a range of fields. Future research should aim at a marriage of these approaches, and at developing models capable of handling the full range of natural river types from braided to meandering. Another important parallel goal is the development of models for the mean behaviour of braided river systems. The first goal is to predict mean slope, depth, velocity, etc. from total water and sediment fluxes, and grain-size distribution. One can average the shallow-water and sediment-flux equations in a manner analogous to Reynolds averaging. This produces viable models, but just as for turbulence, adds new parameters that must be measured or estimated from physical arguments. Application of such averaging techniques to modelling rivers is only just beginning.