Overtopping is one of the major causes of dam and levee earthen embankment failures. The mechanism of breach caused by overtopping erosion is a complicated process but commonly modelled as either head-cut starting from the toe of the embankment slope progressing upward, or as surface erosion starting from the embankment crest. The two mechanisms are modelled for cohesive and non-cohesive soils, respectively. However, the distinction between the two types of soils from the erodibility aspect is not well established. In this paper, overtopping erosion of different soil mixes is addressed through sediments transport models. The paper presents results from small scale breach experiments on a levee section constructed from four compacted soil mixes of clayey and silty sand with and without fine gravel. Simulation of the small scale tests was performed using two dimensional shallow water (2DSW) hydrodynamic model and a sediment transport library (SEDLIB). The experiment results indicate that for silty sand mixes, erosion start at the crest and progresses downward, while erosion for the clayey sand mixes starts close to the toe and progresses upward. The presence of pea gravel size particles in the mixes slows down the erosion process and time to breach as they do not erode at the same rate as the finer particles. 2DSW-SEDLIB simulation results are presented and compared to the experimental results.

In this paper, watercraft and ship simulation is summarized, and the way that it can be extended through realistic physics is explored. A hydrodynamic, data-driven, immersive watercraft simulation experience is also introduced, using the Unreal Engine to visualize a Landing Craft Utility (LCU) operation and interaction with near-shore waves in virtual reality (VR). The VR application provides navigation scientists with a better understanding of how coastal waves impact landing operations and channel design. FUNWAVE data generated on the supercomputing resources at the U.S. Army Corps of Engineers (USACE) Engineering Research and Development Center (ERDC) are employed, and using these data, a graphical representation of the domain is created, including the vessel model and a customizable VR bridge to control the vessel within the virtual environment. Several dimension reduction methods are being devised to ensure that the FUNWAVE data can inform the model but keep the application running in real time at an acceptable frame rate for the VR headset. By importing millions of data points output from the FUNWAVE version 3.4 software into Unreal Engine, virtual vessels can be affected by physics-driven data.

Gravity driven flows such as debris, pyroclastic, avalanche, landslides etc. pose a great threat to life and property. In recent years rainfall combined with prior fire events have resulted in the generation of debris flows in the United States and elsewhere, landslides and mud flows are common occurrences in several regions of  the world where monsoon rains cause soils to saturate, slump and then flow. In some regions these flows take the form of sand, boulders or other cohesionless material generated flows, and avalanches. These flows exhibit non-Newtonian flow characteristics, and provide a challenging engineering problem. These problems arise in the prediction of these flows as well as devising engineering solutions to alleviate danger these pose to the public. Since the advent of numerical modelling, engineers and scientists have used shallow-water equation based mathematical equations to simulate Newtonian flows. In the recent past researchers have attempted to use modifications to the stress terms in the shallow-water equations to account for non-Newtonian behaviour. However these modifications, in general, rely on just one or two of the non-Newtonian formulations to mathematically represent and then numerically simulate non-Newtonian flows. The non-Newtonian behaviour of flows is dynamic, and can change non-Newtonian states depending upon a variety of properties. These properties are inherent to the flows and depend upon the formative process, composition, as well as grain sizes of the debris. Therefore, the requirement is that of a mathematical and numerical description that accounts for these changing states. The Engineer Research and Development Centre (ERDC) of the U.S. Army Corps of Engineers (USACE) has developed a library of debris processes, DebrisLib. This, model agnostic, debris processes library can be linked to any shallow-water based hydrodynamic driver to enable the simulation of debris flows, and the changing non-Newtonian state of the debris flow. This presentation will demonstrate the mathematical development, and incorporation of DebrisLib into the USACE finite element and adaptive meshing software Adaptive Hydraulics (AdH). The implementation will be demonstrated using application to flume tests, avalanches as well as landslides.

The tidal energy resource in the San Francisco Bay (USA) is investigated using of high-resolution numerical modelling and spatial analysis. The system is analyzed for tidal energy potential under various conditions including low, mean, average and high freshwater inflows. The study approached the problem using high resolution numerical modeling that followed a robust moel validation effort and demonstrated the applicability of numerical modelling for identifying the most appropriate areas for tidal stream energy conversion. Future work will incorporate the effects of tidal energy converters on the circulation regime within the san Francisco Bay Estuary and the quantification of ecological impacts.

In coastal and estuarine environments, runoff from the inland merges with ocean waters. During tropical storms or heavy rainfall events, the comb |

Habitat structures such as the Interception Rearing Complexes (IRC) are intended to aid endangered species such as the larval pallid sturgeon by increasing the movement of larval sturgeon out of the main river channel and into the channel margin through the construction or modification of river training structures. The studied IRC are designed to create fish pathways that access the lower velocities and generally shallower depths in the channel margin where juvenile sturgeon have a chance to mature in areas with critical food resources. A Two-Dimensional (2D) Adaptive Hydraulics/Sediment Library (AdH/SEDLIB) depth-averaged, shallow-water, finite element model has been created to study the potential effects that the construction of an IRC may have on other factors, such as long-term bed morphology, navigation, velocity distribution, water surface elevations, and potential flood risk. The model simulates a stretch of river under consideration for the construction of IRC structures. First, the model was set up with pre-existing riverbed and structure geometry. The model was validated for a period between 2017-2020. After calibration, the model was run with the implementation of the proposed IRC structure geometry and compared to system behavior without IRC construction. The validated model was used to evaluate the effects of the proposed IRC on other river processes, by performing simulations both with and without the implementation of the IRC and analyzing inter-model comparisons. The presentation will focus on the details of the modeling system including numerics, application and analysis of results.