CHARACTERIZATION OF INTERTIDAL ZONE CREEK NETWORKS

    The objectives of this study are to quantify intertidal zone creek network properties, and to test for power law scaling in network properties by applying Hack’s Law to creek networks in North Inlet, South Carolina.  Hack’s Law, L=cAⁿ, is a power function relating stream length and drainage basin area in terrestrial systems, where L is the main stream length, c is the y-intercept, A is the drainage basin area, and n is the slope of the best-fit line.  In terrestrial systems, A is typically defined by topographic highs representing flow divides.  In the intertidal zone the corresponding network boundaries however are not easily defined because of the low relief and frequent tidal inundation of network divides.  Consequently, we modified Hack’s A from basin area to individual marsh island area.  A typical terrestrial relationship for Hack’s Law is L=1.4A^0.5-0.7.  Evaluating Hack’s Law using basin area and island area at North Inlet gives L=3.29A^0.77 and L=8.42A^0.89, respectively.  The exponent n suggests that tidal channel networks tend toward elongation more than terrestrial networks.  The y-intercept c shows that a creek length of ~3.3 units is sustained by a basin area of 1.0 square unit.  An island area of 1.0 square unit supports a creek length of ~8.4 units.  This implies that island length and width may constrain the development of intertidal zone creek networks.  While this study indicates that a power law relationship does exist in intertidal zone creek network systems, the question of whether to use drainage area or island area for applying Hack’s Law to marsh creek networks is unresolved.