Hydropedology and Surface/Subsurface Runoff Processes

Abstract

The role of soils has long been recognized as critical to rainfall–runoff processes in watersheds. Hydropedology is an emerging interdisciplinary field that integrates pedology, hydrology, geomorphology, and other related bio‐ and geosciences to study interactive pedologic and hydrologic processes and the landscape–soil–hydrology relationships across space and time. This article presents an overview of hydropedology's contributions to the understanding and modeling of surface/subsurface runoff processes, especially the diagnosis of soil features that can help answer “why‐type” questions in watershed hydrology and the ubiquitous nature of preferential flow and its networks. We highlight two bottlenecks for advancing watershed hydrology and hydropedology: a conceptual bottleneck of modeling subsurface preferential flow networks and a technological bottleneck of nondestructively mapping or imaging subsurface architecture. Quantification of “soil architecture” at various scales and the identification of “hydropedologic functional units” in different landscapes offer promising potentials to advance hydrologic modeling. We present the information of linking surface/subsurface runoff processes to pedologic understanding at three scales of microscopic (macropores and aggregates), mesoscopic (horizons and pedons), and macroscopic (hillslopes and catchments) levels. Various examples from the literature are synthesized to illustrate the key points. Further research needs are suggested in the end.

Groundwater recharge in Pleistocene sediments overlying basalt aquifers in the Palouse Basin, USA: modeling of distributed recharge potential and identification of water pathways

“…This counter balance between ET, P, and percolation implies that close agreement between simulated and observed streamflow does not mean the model accurately predicts percolation. Given the detailed studies of SMR at smaller watersheds near PC watershed discussed in the preceding, which showed very good to excellent agreement with distributed observations of perched water tables (Brooks et al 2007;Lin et al 2008), it is unlikely, however, that the relative distribution of simulated percolation is misrepresented by the model. Hence, the distribution of simulated percolation taking into account soil thickness and underlying restrictive soil layers is useful for identifying regions having a relatively high potential for recharge to the Wanapum basalt aquifer formation.…”

Earth's Critical Zone and hydropedology: concepts, characteristics, and advances

“…Interfaces between soil horizons with different textures or structures also often trigger preferential flow, and thus can impact the scaling of flow, transport, and reaction processes. Such interfaces are also important in defining at what depth a soil profile will begin to saturate and at what time of a year, giving rise to various runoff patterns in catchments (Lin et al, 2008b).…”

“…Catenae in different climatic and physiographic regions may exhibit markedly different relationships between soil and hydrologic properties (e.g., Schaetzl and Anderson, 2005;Lin et al, 2006b;Wilcox et al, 2007;Lin et al, 2008b). Drainage condition, water table depth, and fluxes of water, solutes, and sediments typically differ in soils along a catena (Fig.…”

“…Soil macro-and micro-morphology have long been used to infer soil moisture regimes, hydraulic and biogeochemical properties, and landscape processes (Lilly and Lin, 2004;Lin et al, 2008b). In particular, water-dominated pedogenesis leads to so-called soil hydromorphology (Figs.…”

“…-New ways of characterizing and mapping soils could be improved by linking to hydrology, such as delineating hydropedologic functional units as soil-landscape units with similar pedologic and hydrologic functions (Lin et al, 2008b);…”