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let's try this again.
hydrology 2
a river's kinetic energy comes from its potential energy. the kinetic energy is used in overcoming friction, transporting load, and erosion. laminar flow occurs in viscous liquids, but turbulent flow occurs in water, so lots of energy is lost.
manning's equation states that a river's velocity increases with increasing gradient of channel and hydraulic radius (cross-sectional area over wetted perimeter), but decreases with increasing coefficient of roughness.
velocity affects a river's efficiency. doubling the velocity quadruples the kinetic energy it possesses. river competence (weight of load carried) varies with the sixth power of velocity, while river capacity (volume of load carried) varies with the third power of velocity. the hjulstrom curves show us that as a river's velocity drops, the heavier and larger materials are deposited first, and only at very low speeds can fine particles be deposited. this explains the formation of levees.
there are four erosion processes: abrasion, hydraulic action, attrition, solution. erosion leads to vertical downcutting, whose rate increases with river rejuvenation, lateral erosion, and headward erosion.
there are four transportation processes: traction, saltation, suspension, solution. bedload can become suspended load when river velocity is sufficiently high.
the hjulstrom curves consist of the competent velocity curve and the settling velocity curve. competent velocity is the minimum velocity required to erode a particle of a certain size. settling velocity is the minimum velocity required to transport a particle of a certain size.
features associated with river deposition are alluvial fans, levees, floodplains, and point bars.
three types of rivers: straight, meandering, braided.
things associated with meandering rivers: concave bank erosion, river cliffs, convex bank deposition, point bars, thalweg, helicoidal flow, ox-bow lakes, meander movements.
things associated with braided channels: markedly seasonal river regimes, incoherent banks, high width-depth ratio, anabranches, mid-channel bars, strong erosion during high discharge, great deposition during low discharge, steep channels.
drainage basin analysis involves strahler's method of stream order analysis, bifurcation ratio, and drainage density.
-fin
hydrology 2
a river's kinetic energy comes from its potential energy. the kinetic energy is used in overcoming friction, transporting load, and erosion. laminar flow occurs in viscous liquids, but turbulent flow occurs in water, so lots of energy is lost.
manning's equation states that a river's velocity increases with increasing gradient of channel and hydraulic radius (cross-sectional area over wetted perimeter), but decreases with increasing coefficient of roughness.
velocity affects a river's efficiency. doubling the velocity quadruples the kinetic energy it possesses. river competence (weight of load carried) varies with the sixth power of velocity, while river capacity (volume of load carried) varies with the third power of velocity. the hjulstrom curves show us that as a river's velocity drops, the heavier and larger materials are deposited first, and only at very low speeds can fine particles be deposited. this explains the formation of levees.
there are four erosion processes: abrasion, hydraulic action, attrition, solution. erosion leads to vertical downcutting, whose rate increases with river rejuvenation, lateral erosion, and headward erosion.
there are four transportation processes: traction, saltation, suspension, solution. bedload can become suspended load when river velocity is sufficiently high.
the hjulstrom curves consist of the competent velocity curve and the settling velocity curve. competent velocity is the minimum velocity required to erode a particle of a certain size. settling velocity is the minimum velocity required to transport a particle of a certain size.
features associated with river deposition are alluvial fans, levees, floodplains, and point bars.
three types of rivers: straight, meandering, braided.
things associated with meandering rivers: concave bank erosion, river cliffs, convex bank deposition, point bars, thalweg, helicoidal flow, ox-bow lakes, meander movements.
things associated with braided channels: markedly seasonal river regimes, incoherent banks, high width-depth ratio, anabranches, mid-channel bars, strong erosion during high discharge, great deposition during low discharge, steep channels.
drainage basin analysis involves strahler's method of stream order analysis, bifurcation ratio, and drainage density.
-fin
posted by ivan at 10:48 PM
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