FLOOD06421

• County: Statewide
• Basin: Statewide
• Title: Highways in the River Environment
• Date: 2/1/1990
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Velocitv-Weiqhted Sediment Concentration - The dry weight of sediment
discharged through a cross section during unit time.

Vertical (full-heiqhtl Abutment - An abutment, usually with wingwalls, that has
no fill slope on its streamward side.

Wanderinq Channel - A channel exhibiting a more or less non-systematic
process of channel shifting" erosion, and deposition, with no definite meanders or
braided pattern.

Wanderinq Thalweq - A thalweg whose position in the channel shifts during
floods and typically serves as an inset channel that transmits all or most of the
streamflow at normal or lower stages.

Watershed - See draina'3e basin.

Waterway Openinq Width (area) - Width (area) of bridge opening at (below) a
specified stage, measured normal to principal direction of flow.

Wave Attack - Impact of waves on a stream bank.

Wave Period - Time period between arrivals of successive wave crests at a
point.

Wave Run-Up - Height. to which water rises above still-water level when waves
meet such things as a beach or wall.

Weephole - A hole in an impermeable wall or revetment to relieve the neutral
stress or porewater pressure.

Windrow Revetment - A row of stone (called a windrow) placed on top of the
bank landward of an eroding stream bank. As erosion continues the windrow is
eventually undercut, launching the stone downslope, thus armoring the bank face.

Wind Set-Down - Corresponding f<lll in level at the windward side.

Wind Set-Up - Rise in level at th~ leeward side of a body of water, due to wind
stresses on the surface.

Wire Mesh - Wire woven to form a mesh, the openings of which are of suitable
size and shape to enclose rock or broken concrete, or to be used on fence-like spurs
and retards.

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