191. A Model of Rill Erosion by Snowmelt

Measurements of rill flow profiles, water discharges, sediment concentration, temperature of water, soil and air were conducted during spring snowmelt events on an experimental station located 100 km south of Moscow, Russia. The results indicate that: (a) the rill profiles have, as a rule, a triangular form; (b) the sidewall slope of a rill is close to the natural slope for non-frozen soils and depends on the water discharge; and (c) in general, the thawing of the soil surface occurs faster than the soil particle detachment. As the knowledge of frozen soil erosion mechanics is limited, a number of assumptions have to be made for the model design. In detail, the Snow Melt Erosion Model (SMEM) includes the Chezy-Manning's equation, the Goncharov's equation to calculate bottom flow velocity, the Mirtskhulava's equation for estimation of soil particle detachment and the Kuznetsov's equation for critical bottom flow velocity. The model is tested with 7 years of data from two runoff plots located in the Central-Chenozem Zone of Russia (soil type is chernozem).