ANALYTICAL MODEL OF SPIT EVOLUTION AT INLETS

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examined from the perspective of process-based modeling. Hydrodynamic

and morphologic processes controlling spit evolution are first identified and

classified according to major spit parameter and time scale. An analytical

model of spit evolution is then presented that describes cause and effect

between selected spit parameters and the acting processes, focusing on spit

elongation and its rate of change. Predictions and trends from the model are

examined by reference to measurements of spit growth in Corpus Christi

Bay, Texas, and to spits generated in a movable-bed physical model. It is

concluded that considerable progress can be made in quantifying spit

dynamics at inlets.

INTRODUCTION

Spits are organized surface-piercing accumulations of sediment that grow by

transport directed from a landmass or sediment source toward a water body. Spits

can form at the ocean and bay sides of inlets and are of interest both for

understanding inlet morphodynamics and for managing navigation channels and

inlets. Inlet closure through spit development has implications for water quality, as

well as for commercial and recreational navigation. Submerged shoals that grow

from larger landmasses, such as shoals that form around the ends of jetties or the

bypass bars that extend toward the shore from ebb-tidal shoals, can be considered

subaqueous spits governed by similar processes.

1) U.S. Army Engineer Waterways Experiment Station, Coastal and Hydraulics Laboratory,

3909 Halls Ferry Road, Vicksburg, MS 39180 USA. n.kraus@cerc.wes.army.mil

Kraus