EM 1110-2-1100 (Change 1)
31 Jul 03
FLUVIAL
Of or pertaining to rivers; produced by the action of a river or stream (e.g., fluvial sediment).
FLUSHING TIME
The time required to replace all the water in an ESTUARY, HARBOR, etc., by action of current and tide.
FOAM LINE
(1) The front of a wave as it advances shoreward, after it has broken. (2) Lines of foam such as those which move
around the head of a RIP.
FOLLOWING WIND
Generally, the same as a tailwind; in wave forecasting, wind blowing in the direction of ocean-wave advance.
FOREDUNE
The front DUNE immediately behind the backshore.
FORERUNNER
Low, long-period ocean SWELL which commonly precedes the main swell from a distant storm, especially a
tropical cyclone.
FORESHORE
The part of the shore, lying between the crest of the seaward berm (or upper limit of wave wash at high tide) and the
ordinary low-water mark, that is ordinarily traversed by the uprush and backrush of the waves as the tides rise and fall. See
BEACH FACE. (See Figure A-1)
FORE REEF
The seaward side of a REEF (usually coral); in places a steep slope covered with reef talus.
FORWARD SPEED (hurricane)
Rate of movement (propagation) of the hurricane eye in meters per second, knots, or miles per hour.
FREEBOARD
At a given time, the vertical distance between the water level and the top of the structure. On a ship, the distance
from the waterline to main deck or gunwale.
FRINGING ISLANDS
A series of islands that fringe, or mask, a mainland coast often known as BARRIER ISLANDS. The waters
landward of such islands are sometimes treated as high seas enclaves or as inland waters.
FRINGING REEF
A coral REEF attached directly to an insular or continental shore. There may be a shallow channel or lagoon
between the reef and the adjacent mainland.
FRONT OF THE FETCH
In wave forecasting, the end of the generating area toward which the wind is blowing.
FROUDE NUMBER
The dimensionless ratio of the inertial force to the force of gravity for a given fluid flow. It may be given as Fr = V
/Lg where V is a characteristic velocity, L is a characteristic length, and g the acceleration of gravity - or as the square
root of this number.
FULLY-DEVELOPED SEA
The waves that form when wind blows for a sufficient period of time across the open ocean. The waves of a fully
developed sea have the maximum height possible for a given wind speed, FETCH and duration of wind.
A-32
Appendix A Glossary of Coastal Terminology
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