Depression storage and infiltration effects on overland flow depth-velocity-friction at desert conditions: field plot results and model

Abstract

Abstract. Water infiltration and overland flow are relevant in considering water partition among plant life forms, the sustainability of vegetation and the design of sustainable hydrological models and management. In arid and semi-arid regions, these processes present characteristic trends imposed by the prevailing physical conditions of the upper soil as evolved under water-limited climate. A set of plot-scale field experiments at the semi-arid Patagonian Monte (Argentina) were performed in order to estimate the effect of depression storage areas and infiltration rates on depths, velocities and friction of overland flows. The micro-relief of undisturbed field plots was characterized at z-scale 1 mm through close-range stereo-photogrammetry and geo-statistical tools. The overland flow areas produced by controlled water inflows were video-recorded and the flow velocities were measured with image processing software. Antecedent and postinflow moisture were measured, and texture, bulk density and physical properties of the upper soil were estimated based on soil core analyses. Field data were used to calibrate a physically-based, mass balanced, time explicit model of infiltration and overland flows. Modelling results reproduced the time series of observed flow areas, velocities and infiltration depths. Estimates of hydrodynamic parameters of overland flow (Reynolds-Froude numbers) are informed. To our knowledge, the study here presented is novel in combining several aspects that previous studies do not address simultaneously: (1) overland flow and infiltration parameters were obtained in undisturbed field conditions; (2) field measurements of overland flow movement were coupled to a detailed analysis of soil microtopography at 1 mm depth scale; (3) the effect of depression storage areas in infiltration rates and depth-velocity friction of overland flows is addressed. Relevance of the results to other similar desert areas is justified by the accompanying biogeography analysis of similarity of the environment where this study was performed with other desert areas of the world.

A new modeling approach for simulating microtopography-dominated, discontinuous overland flow on infiltrating surfaces

“…It has been found that surface microtopography controls spatial and temporal variations of overland flow depth and velocity [47,27,18,19]. In addition, greater depths of water ponded in microtopographic depressions tend to increase infiltration [18,37] and unsaturated flow [30]. The spatial variability in surface microtopography also affects surface-subsurface exchange and runoff generation for riparian wetlands [20].…”

Assessing the performance of structure‐from‐motion photogrammetry and terrestrial LiDAR for reconstructing soil surface microtopography of naturally vegetated plots

“…In addition, soil microtopography is useful in describing other physical, hydrologic and biological processes. It was shown for example to control infiltration and runoff amounts (Romkens et al, 2001;Thompson et al, 2010) and plays a central role in ecohydrologic processes such as rainwater redistribution, seed displacement and plant competition (Rossi and Ares, 2012b).…”

Potential of time‐lapse photography for identifying saturation area dynamics on agricultural hillslopes

“…Based on these considerations, visual terrestrial imagery is appealing for monitoring saturation areas that provides complementary information to hydrograph measurements and thus helps better understand hydrological processes. Rossi and Ares () utilized digital camera imagery to capture the microtopographic effect on run‐off movement and depression storage without disturbing the experimental field, a common problem that may produce artefacts in the observed flow characteristics. Similarly, Orlandini et al () used camera imagery to evaluate the dominant classes of flow direction methods in terrain‐based flow direction predictions.…”