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Sediment creep is ubiquitous and precedes Sediment creep is ubiquitous and precedes failure (e.g. landslides) in most landscapes. Accurate modeling of sediment creep is therefore crucial for predicting both the long-term (>10 000 years) evolution of landscapes and the short-term (minute to centuries) evolution of landscapes and infrastructures. Current sediment creep transport laws used in landscape modeling are determined empirically over geological time scales and are diffusion-like (Roering et al,2001); yet the mechanics of sediment creep on all time scales remain poorly understood. As a result, creep models used in civil engineering, materials science, and geomorphology are largely disconnected in time scales, goals, and approaches. In particular, excess porous flow from rain infiltration is currently not a governing parameter of any creep model, while large rain events are known to trigger landscape failures.</br>Houssais et al. (2021) showed experimentally for the first time, that porous flow can be a leading cause of creep, and ultimately the failure (avalanching) of sediment piles, for flow strength (or pore pressure) far lower than classically admitted. Building on the results from Houssais et al., we propose a new equation for sediment creep consistent with the general formalism of the mechanical creep of disordered materials. In our equation, the creep sediment flux is a function of: topographic slope (similar to the equation from Roering et al.), porous flow intensity, grains and fluid properties, and, importantly, time. </br></br>We present here the first results of landscape dynamics from the implementation of our new sediment creep function in landlab, for the case of idealized berms (or coastal natural dams), before they breach. The long-term goal of this effort is to compare the model to our topographic and hydrogeologic observations of berms (pre-)breaching on the coast of Monterey County, CA, that occur each winter, as large rain episodes hit the land. This specific case is a good way to test our model validity over time scales from 1 minute to 1 month. In our presentation, we will show preliminary results of the berms creep (pre-breaching) dynamics, using over-simplified equations for the groundwater flow. In the future, we intend to develop a Landlab component of our new creep function, which could be used with Groundwaterdupuitpercolator, a landlab component recently developed to model groundwater flow while modeling landscape dynamics (Litwin et al., 2020, 2022).</br>In the end, once this model is validated, it will allow us to model sediment creep at all time and rate scales, and better predict chances of, and monitor, sedimentary failures, such as breaching and landslides. Our new model for sediment creep fundamentally addresses our needs for better understanding and forecasting landscape response to changing climate patterns. </br></br>Houssais, M., C. Maldarelli, and J. F. Morris, “Athermal sediment creep triggered by porous flow,” Physical Review Fluids, vol. 6, no. 1, p. L012301, 2021.</br></br>Litwin, D. G., G. E. Tucker, K. R. Barnhart, and C. J. Harman, “Groundwaterdupuitpercolator: A landlab component for groundwater flow,” Journal of Open Source Software, vol. 5, no. 46, p. 1935, 2020.</br></br>Litwin, D. G., G. E. Tucker, K. R. Barnhart, and C. J. Harman, “Groundwater affects the geomorphic and hydrologic properties of coevolved landscapes,” Journal of Geophysical Research: Earth Surface, vol. 127, no. 1, p. e2021JF006239, 2022.</br></br>Roering, J. J., J. W. Kirchner, L. S. Sklar, and W. E. Dietrich, “Hillslope evolution by nonlinear creep and landsliding: An experimental study,” Geology, vol.liding: An experimental study,” Geology, vol.  
Using a new fundamental equation of sediment creep to model coastal breaching and landsliding  +
Worcester  +
United States  +, Germany  +  and France  +
Mara  +, David  +  and Olivier  +
Naval Postgraduate School  +, GeoForschungsZentrum  +  and Institut de Physique du Globe de Paris  +
Orescanin  +, Litwin  +  and Devauchelle  +
Monterey  +, Potsdam  +  and Paris  +
mhoussais@clarku.edu  +
Physics, Clark University  +
2) Vegetation as ecogeomorphic features  +
3) Parameterizing human dynamics in geomorphic models: learning from coastal barrier evolution models  +
3) New features and basic usage of the GeoClaw software for depth-averaged flow  +
Massachusetts  +
United States  +
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13:33:56, 26 February 2024  +
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15:03:49, 26 February 2024  +
{{{OtherCountry}}}  +
California  +
Terrestrial Working Group  +, Coastal Working Group  +, Hydrology Focus Research Group  +, Critical Zone Focus Research Group  +  and Ecosystem Dynamics Focus Research Group  +