Channel morphology of the ephemeral streams in Southeast Arizona is influenced by both lateral and vertical channel changes occurring during major floods. The recent floods in the area have caused a variety of erosion hazards including bank erosion, channel migration, bed degradation. and excessive scour at bridge abutments and piers. The floods of 1983 and 1993 were comparable in terms of peak discharge and duration, but the estimated total damage during the 1993 flood was much lower (about 14%), because of extensive soil cement bank protection constructed along the major rivers after the 1983 flood. The performance of the soil cement bank and bed stabilization during the 1993 flood (protected banks were generally unaffected by flood flows) thus demonstrates the effectiveness of soil cement as the materials for erosion protection measures in ephemeral streams. Advantages of soil cement protection are its ease of construction. low cost, use of in-place soil and environmental attractiveness because of its natural appearance. A new approach for protection against bank erosion and channel migration, using flexible spurs consisting of a series of pile-supported permeable panels of synthetic nets, is described.
展开▼
