Spatial controls on groundwater response dynamics in a snowmelt-dominated montane catchment

Abstract

Abstract. The role of spatial variability in water inputs on runoff dynamics has generally not received as much research attention as topography and soils; however, the influence of topography and forest cover on snow surface energy exchanges can result in asynchronous snowmelt throughout a catchment, complicating the space–time patterns of runoff generation. This study investigates temporal variation in the relative importance of spatial controls on the occurrence, duration, and timing of shallow groundwater response, utilizing a highly distributed monitoring network in a snowmelt-dominated montane catchment in western Canada. The study findings indicate that deep-soil hydraulic conductivity is a first-order control on the spatial distribution of sites that generate shallow groundwater response versus sites that experience only deep percolation. Upslope contributing area and slope gradient are first-order controls on the duration of groundwater response during peak-flow, recession-flow, and low-flow periods. Shallow runoff response areas expand and contract throughout these periods and follow the general spatial patterns of topographic convergence. However, spatial controls on the timing, intensity, and quantity of snowmelt and controls on vertical versus lateral flux partitioning in the soil overwhelm the influence of topographic convergence on runoff patterns during early spring freshet periods. The study findings suggest that various topographic indices and topography-based rainfall runoff models would not likely be good predictors of runoff patterns in snowmelt-dominated montane catchments during early phases of the spring freshet, but would increase in importance as the freshet and post-freshet periods proceed.

Does hillslope trenching enhance groundwater recharge and baseflow in the Peruvian Andes?

“…Differentiating between the impact of the trenching location and the flat terrain is difficult because of the overlap in these terrain characteristics. This is consistent with Smith, Moore, Weiler, and Jost (), who found that the spatial distribution of inputs, in their case snow melt, is an important control on stream response.…”

Spatial organization of groundwater dynamics and streamflow response from different hydropedological units in a montane catchment

“…However, the correlation decreased during rainfall events, becoming weakest in the largest events. This is consistent with the effects of rainfall input, limited storage and surface flow redistribution overwhelming the normal topographic controls (Smith et al, 2014). This is somewhat different to recent work by Rinderer et al (2014) who found in a pre-alpine catchment dominated by subsurface storm flow that correlations were strongest when GW levels were high and changed slowly, e.g.…”

“…However, the correlation decreased during rainfall events, becoming weakest in the largest events. This is consistent with the effects of rainfall input, limited storage and surface flow redistribution overwhelming the normal topographic controls (Smith et al ., ). This is somewhat different to recent work by Rinderer et al .…”

Groundwater similarity across a watershed derived from time‐warped and flow‐corrected time series

“…However, for a better understanding of runoff generation processes and runoff source area dynamics, the groundwater response during events is more relevant than during the recession or baseflow periods. To avoid the bias toward low flows, it is useful to apply the Flow‐corrected Time Transformation [ Rodhe et al ., ; Smith et al ., ]. In our case this involved stretching the time axis of the specific discharge time series, measured at the catchment outlet, proportional to the specific discharge during periods with above‐average specific discharge, and shrinking the time axis for all periods with below‐average specific discharge (Figure b).…”