干旱区生态环境知识资源中心

A kinematic wave model of overland flow was used to calculate hydraulic roughness coefficients for earth covers and native hillslope surfaces at a waste burial site located in a cold-desert region of southeast Idaho. Manning n roughness coefficients were greater on earth cover plots planted to crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.] (a bunchgrass, average n = 0.076) than on those planted to streambank wheatgrass [Elymus lancelolatus (Scribner & J. G. Smith) Gould] (a sodgrass, average n = 0.030). Mound and intermound microtopography strongly influenced overland flow geometry on the bare native hillslope plots resulting in low apparent roughness values (average n = 0.013). Time-related changes in hydraulic roughness appeared to be caused by development of a rain-induced crust on exposed soil surfaces that reduced infiltration and increased plot smoothness.