Table 2. Parameters controlling spit geometry and evolution, and the associated process (from Kraus 1999)

Table 2. Parameters controlling spit geometry and evolution, and the associated

processes (from Kraus 1999)

Spit

Long Term1

Parameter

Short Term

Sediment supply; geologic

Longshore transport rate; proximity to

controls; breaching (bayward

inlet channel; strength of channel

or seaward); cyclic &

Length

intermittent forcing

current

Longshore transport rate; grain size;

proximity to inlet channel; beach slope

and depth-contour gradients parallel to

Elongation

Cyclic and intermittent

forcing2

spit

speed

Run-up elevation; tidal range; depth-

Width

contour gradients perpendicular to spit

(see Overwash fans below)

Dunes and other blocking

features; depth of receiving

bay or lagoon

Overwash fans

Storm surge; frequency of storms

Elev. above

Aeolian transport; relative

mean sea level

Run up; tidal range

sea-level change; tsunami

Depth of

Wave height and period; tidal range;

closure

grain size

Extreme storms; elapsed time

Tendency to

Proximity to channel; channel current;

recurve

wave focusing; extreme storms

Cyclic and intermittent forcing

1. Long-term processes encompass those of short-term processes in same category.

2. Cyclic and intermittent forcing arises from seasonal and annual changes in wind and

waves, arrival of storms and weather fronts, annual and inter-annual change in water

level, etc.