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How Important Is Connectivity for Surface Water Fluxes? A Generalized Expression for Flow Through Heterogeneous Landscapes
Author(s) -
Larsen Laurel G.,
Ma Jie,
Kaplan David
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075432
Subject(s) - percolation (cognitive psychology) , environmental science , wetland , flow (mathematics) , hydrology (agriculture) , channel (broadcasting) , vegetation (pathology) , fractal dimension , streams , water flow , surface water , geology , fractal , soil science , ecology , computer science , mathematics , geotechnical engineering , biology , geometry , medicine , computer network , neuroscience , environmental engineering , mathematical analysis , pathology
How important is hydrologic connectivity for surface water fluxes through heterogeneous floodplains, deltas, and wetlands? While significant for management, this question remains poorly addressed. Here we adopt spatial resistance averaging, based on channel and patch configuration metrics quantifiable from aerial imagery, to produce an upscaled rate law for discharge. Our model suggests that patch coverage largely controls discharge sensitivity, with smaller effects from channel connectivity and vegetation patch fractal dimension. However, connectivity and patch configuration become increasingly important near the percolation threshold and at low water levels. These effects can establish positive feedbacks responsible for substantial flow change in evolving landscapes (14–36%, in our Everglades case study). Connectivity also interacts with other drivers; flow through poorly connected hydroscapes is less resilient to perturbations in other drivers. Finally, we found that flow through heterogeneous patches is alone sufficient to produce non‐Manning flow–depth relationships commonly observed in wetlands but previously attributed to depth‐varying roughness.