Simulation of alluvial fan deposition by a random walk model

The results of this study suggest that a, digital model based on a random walk may be used to simulate alluvial fan deposition. The model is in three dimensions, is dynamic in time and space, and employs two independent stochastic events: an uplift of the mountain basin contributing sediments and a storm large enough to result in fan deposition. A random walk, each step governed by the gradient and momentum of flow, determines the pattern of deposition. Results of the simulation are printed as geologic maps and sections. The general form of the simulated deposits is that of an alluvial fan, the pattern of simulated flows resembles that of real flows, and fan facies show a concentration of debris flows near the apex and a particle size decrease in water flow deposits downfan. The model could aid in the development of data collection systems, the estimation of aquifer parameters in undeveloped areas, better interpretation of aquifer tests, and improvement in the accuracy of test‐hole correlations.