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Sensitivity analysis of hydraulic conductivity and Manning's n parameters lead to new method to scale effective hydraulic conductivity across model resolutions
Author(s) -
M. Foster Lauren,
M. Maxwell Reed
Publication year - 2018
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.13327
Subject(s) - hydraulic conductivity , discretization , sensitivity (control systems) , environmental science , hydrology (agriculture) , conductivity , infiltration (hvac) , scale (ratio) , hydrological modelling , soil science , parametric statistics , hydrogeology , streamflow , subsurface flow , drainage basin , geology , meteorology , mathematics , geotechnical engineering , statistics , groundwater , soil water , climatology , physics , geography , mathematical analysis , cartography , quantum mechanics , electronic engineering , engineering
Hydrological modelling is an important tool for research, policy, and management, but uncertainty remains about parameters transferability from field observations made at small scale to models at the catchment scale and larger. This uncertainty compels the need to develop parameter relationships that are translatable across scale. In this study, we compare the changes to modelled processes as resolution is coarsened from 100‐m to 1‐km in a topographically complex, 255‐km 2 Colorado River headwater catchment. We conducted a sensitivity analysis for hydraulic conductivity ( K ) and Manning's n parameters across four orders of magnitude. Results showed that K acts as a moderator between surface and subsurface contributions to streamflow, whereas n moderates the duration of high intensity, infiltration‐excess flow. The parametric sensitivity analysis informed development of a new method to scale effective hydraulic conductivity across modelling resolutions in order to compensate for the loss of topographic gradients as resolution is coarsened. A similar mathematical relationship between n and lateral resolution changes was not found, possibly because n is also sensitive to time discretization. This research provides an approach to translate hydraulic conductivity parameters from a calibrated coarse model to higher resolutions where the number of simulations are limited by computational demand.