Sensitivity analysis of hydraulic conductivity and Manning's n parameters lead to new method to scale effective hydraulic conductivity across model resolutions

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 tha...

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Bibliographic Details
Published in:Hydrological processes 2019-01, Vol.33 (3), p.332-349
Main Authors: Foster, Lauren M, Maxwell, Reed M
Format: Article
Language:English
Subjects:
Catchment area
Catchment scale
Computer applications
Computer simulation
Duration
Headwater catchments
Headwaters
Hydraulic conductivity
Hydraulics
Hydrologic models
Hydrology
Infiltration
integrated modelling
Manning's n
Mathematical models
Methods
Modelling
parameter estimation
Parameter sensitivity
Parameter uncertainty
Parameters
Policies
Resolution
Rivers
scaling
Sensitivity analysis
Stream discharge
Stream flow
Uncertainty
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Summary: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‐km2 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.
ISSN:0885-6087
1099-1085
DOI:10.1002/hyp.13327