ADDRESSING CONCEPTUAL AND TECHNOLOGICAL BOTTLENECKS TO ADVANCE SUBSURFACE HYDROLOGY

  • Lin, Hangsheng (PI)

Project: Research project

Project Details

Description

Preferential flow and its network have become a frontier in subsurface hydrology. Preferential flow (PF) is a generic term that refers to the process whereby water (and materials carried by water) moves by preferred pathways in an accelerated speed through a fraction of a porous medium, thus bypassing a portion of the matrix. Non-uniform flow is another term commonly used interchangeably with PF. Over the past decades, a variety of PFs have been reported in the literature, including flows caused by macropores or pipes or fractures, soil structure, interfacial layers (especially restrictive layers within or underneath soil profiles), instability of wetting front, water repellency, topography gradient, biological activities, and land use disturbance. Despite significant progress made in the past decades, our ability to determine and predict preferential flow patterns, velocities, and pathways in the subsurface across space and time remains limited. All PFs are fundamentally important as they influence runoff, erosion, water quality, nutrient cycling, biogeochemical processes, ecological functions, gas emission, and contaminant fate in the environment. The value of PFs to ecosystem services has been estimated to be some $304 billion per year globally. Despite the importance and the long recognition of PF in soils, a theory of PF is still lacking, and a firm inclusion of PF in hydrologic models remains a challenge. This is in part due to the lack of a theoretical underpinning for PF occurrence, plus the classical perception that PF is the exception rather than the rule (we call this the conceptual bottleneck). Another reason is the difficulty in observing or monitoring PF in situ and in imaging PF-related subsurface heterogeneity across scalesespecially nondestructively, continuously, and with high enough spatial-temporal resolutions (we call this the technological bottleneck). These two bottlenecks result in the neglect or inadequate treatment of PF in many existing models. This project addresses a fundamental soil hydrological process across various land uses that will have significant impacts on our understanding and practices in watershed management, land use, stormwater management, flooding or drought protection, nutrient cycling, contaminant prevention, and wastewater recycling.

StatusFinished
Effective start/end date7/1/126/30/16

Funding

  • National Institute of Food and Agriculture

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