Effects of Surface Microtopography on Hydrologic Connectivity

Land surface is generally not smooth. The existence of puddles breaks the continuity of various hydrologic features/properties. The spatial connectivity of topographic surfaces has significant influence on a series of hydrologic and geomorphologic processes and results in localized and independent hydrologic mass balance. This study centers on examining the effects of surface microtopography on hydrologic connectivity. An instantaneous-profile laser scanner is utilized to acquire highresolution DEMs of surfaces with varying microtopographic characteristics. A puddle delineation software package is used to delineate the surfaces and quantify the relationships of puddles. Particularly, both structural and functional hydrologic connectivity properties are examined. In addition, the effects of DEM resolutions on hydrologic connectivity are investigated. It is found that the approach of spatial mapping of the connected areas is capable of describing the spatial complexity of connectivity of topographic surfaces. The surfaces of different microtopographic features have unique changing patterns of normalized discharge, which provides promising information to better understand the related hydrologic processes.