Calculation of the rate of erosion in soils and cohesive sediments

The new method for calculating erosion in soils and cohesive (aggregated) s ediments is suggested. It is based on the determination of the probability of soil aggregate detachment from the flow bed upon the stochastic excess o f driving forces over resistance forces. This method permitted us to calcul ate the erosion intensity in cohesive sediments using the parameters of the distribution curves of flow velocity, cohesion and consolidation of sedime nts, and the size of detached aggregates. The nonexponential theoretical re lationships between the erosion intensity and the near-bed flow velocity we re obtained, which disproved the universal character of the widespread expo nential empirical relationships. Upon the small flow velocities, the insign ificant variation in the properties of the eroded sediment changed the eros ion rate considerably; the stochastic variability of erosion agents in spac e and time upon the high flow velocities insignificantly affected the rate of flow bed erosion.