Rudd Creek Mud Flow Simulation, Utah
The alluvial fan of Rudd Creek, near Farmington, Utah, experienced devastating mudflows in May 1983 (USACE, 1988). RiverFlow2D MD Mud and Debris Flow Module was used to replicate the event. The extent of the deposit computed by RiverFlow2D compared well with the observed affected area. The surveyed volume of the sediment deposit was 62,200 m3 and the total volume computed from the model calculated depths was 64,199 m3. According to the observations, the maximum depths occurred near the alluvial fan apex and was near 3.7 m, while the RiverFlow2D computed maximum depth ranges from 3.5 to 3.9 m at the fan apex. Mudflow velocities predicted by the model ranged from 0.3 to 1.2 m/s on the fan which agrees well with the velocities of 0.6-1.2 m/s estimated from eyewitness accounts (USACE, 1988). Close to the fan apex, the observed velocities were less than 3 m/s while the maximum calculated velocities were around 2.6 m/s.