The term bed load or bedload describes particles in a flowing fluid (usually water) that are transported along the bed. Bed load is complementary to suspended load and wash load.
Bed load moves by rolling, sliding, and/or saltating (hopping).
Generally, bed load downstream will be smaller and more rounded than bed load upstream (a process known as downstream fining). This is due in part to attrition and abrasion which results from the stones colliding with each other and against the river channel, thus removing the rough texture (rounding) and reducing the size of the particles. However, selective transport of sediments also plays a role in relation to downstream fining: smaller-than average particles are more easily entrained than larger-than average particles, since the shear stress required to entrain a grain is linearly proportional to the diameter of the grain. However, the degree of size selectivity is restricted by the hiding effect described by Parker and Klingeman (1982), wherein larger particles protrude from the bed whereas small particles are shielded and hidden by larger particles, with the result that nearly all grain sizes become entrained at nearly the same shear stress.
Famous quotes containing the words bed and/or load:
“Romeo. I dreamt a dream tonight.
Mercutio. And so did I.
Romeo. Well, what was yours?
Mercutio. That dreamers often lie.
Romeo. In bed asleep, while they do dream things true.
Mercutio. O then I see Queen Mab hath been with you.
She is the fairies’ midwife, and she comes
In shape no bigger than an agate stone
On the forefinger of an alderman,
Drawn with a team of little atomi
Over men’s noses as they lie asleep.”
—William Shakespeare (1564–1616)
“‘Tis all men’s office to speak patience
To those that wring under the load of sorrow,
But no man’s virtue nor sufficiency
To be so moral when he shall endure
The like himself.”
—William Shakespeare (1564–1616)