Advances in Canadian forest hydrology, 1995-1998

Abstract:Two Precambrian Shield zero-order catchments were monitored from January 2003 to July 2004 to characterize their hydrological and biogeochemical characteristics prior to a forest management experiment. Hydrometric observations were used to examine temporal trends in hillslope-wetland connectivity and the hillslope runoff processes that control wetland event response. The hillslope groundwater flux from the longer transect (E1) was continuous throughout the study period. Groundwater fluxes from a shorter and steeper hillslope (E0) were intermittent during the study period. Large depression storage elements (termed micro-basins) located on the upper hillslope of the E1 catchment appeared to be at least partly responsible for the observed rapid wetland runoff responses. These micro-basins were hydrologically connected to a downslope wetland by a subsurface channel of glacial cobbles that functioned as a macropore channel during episodic runoff events. The runoff response from the hilltop micro-basins is controlled by antecedent water table position and water is quickly piped to the wetland fringe through the cobble channel during high water table conditions. During periods of low water table position, seepage along the bedrock-soil interface from the hilltop micro-basin and other hillslopes maintained hillslope-wetland connectivity. The micro-basins create a dynamic variable source-area runoff system where the contributing area expands downslope during episodic runoff events. The micro-basins occupied 30% of the E1 catchment and are a common feature on the Precambrian Shield.

Section: Introductionmentioning

confidence: 99%

Hillslope hydrology and wetland response of two small zero‐order boreal catchments on the Precambrian Shield

Frisbee¹,

Allan²,

Thomasson³

et al. 2007

“…Buttle et al . () concluded that soil thickness exerted a strong control on the type and relative importance of various runoff processes on the Precambrian Shield. Water inputted to the slope surface of thin soil reached the bedrock as preferential flow through soil macropores and runoff appeared to occur as subsurface stormflow; conversely, areas of thicker soil supplied runoff to the riparian zone largely as groundwater flow.…”

Section: Introductionmentioning

confidence: 96%

Linking soil thickness and plot‐scale hydrological processes on the sloping lands in the Three Gorges Area of China: a hydropedological approach

Cai

et al. 2011

Abstract:The emerging interdisciplinary field of hydropedology promotes synergistic integration of pedology and hydrology to enhance the holistic study of soil-water interactions across space and time. Our study illustrated this integration, exemplifying from plotscale hydrological processes investigations on the sloping lands with different soil thickness in the Three Gorges Area of China. Our aims were to deal with (i) the watershed scale soil thickness survey, soil profiles description and hydrological processes inferential analysis for the plots with typical soil thickness from the pedological perspective, and (ii) the identification of dominant hydrological processes of these plots based on hydrological monitoring under simulated rainfall (designed as 60 mm h À1 ) from the hydrological perspective. The main results can be summarised as follows: (i) soil thickness of the sloping lands exhibited a wide range of variability along hillslopes. Thin soils reflected weaker pedogenesis degrees and less intense human intervention as compared with thick soils. (ii) Deep percolation and subsurface flow were the dominant processes in thin soils, whereas in thick soils, surface flow, deep percolation and storage were the dominant processes. (iii) Regarding to the surface flow, the 23-cm plot was mainly in the form of saturated overland flow, whereas the other plots were Horton overland flow. As to the subsurface flow, both 23-and 31-cm plots mainly took the form of preferential flow, the 59-and 76-cm plots mainly in the form of matrix flow regardless of soil horizon and the 45-cm plot displayed mainly the matrix flow in the A horizon and mainly the preferential flow in the AC horizon. Our study suggested that, relative to its parent disciplines of both pedology and hydrology, hydropedology improved synergies between pedology and hydrology in the plot-scale hydrological processes investigations.

“…Timber harvesting may directly alter ecosystem hydrology by lowering canopy interception and decreasing evapotranspiration (Buttle, Creed, & Pomeroy, ). The resulting increase in available water can increase surface flow and groundwater recharge and decrease soil‐moisture storage potential.…”

Section: Introductionmentioning

confidence: 99%

Hydrologic impact of aspen harvesting within the subhumid Boreal Plains of Alberta

Thompson

Devito

Mendoza

2018

This study examined the hydrological impact of harvesting aspen (Populus tremuloides) within the subhumid Boreal Plains of Alberta, Canada, following clear‐cutting of two stands in successive winters within a small catchment situated in glacial moraine. Impacts were evaluated using a combination of observational data collected from within the harvested catchment and an adjacent reference catchment and numerical simulations conducted with HydroGeoSphere. Sensitivity simulations evaluated the influence of post‐harvest evapotranspiration rates and variability in atmospheric conditions on the range of hydrologic response. Study results indicate that aspen harvesting had limited impact on groundwater levels and streamflows within these hydrologic systems because of the subhumid climate with low frequency of large storms, large soil‐moisture storage capacity of heterogeneous glacial materials, and high evapotranspiration rates of regenerating aspen. Despite an estimated increase in hillslope groundwater levels of up to 3 m, pond and peatland water levels increased by less than 0.3 m and were accompanied by increased streamflows of less than 10 mm. However, predicted increases in groundwater levels and streamflows were sensitive to regenerating aspen evapotranspiration rates, which can be enhanced by appropriate harvesting techniques but may be reduced by climate change. These results are consistent with previous results from within the Boreal Plains but differ from aspen harvesting studies conducted in other settings where appreciable increases in streamflows have been reported. This disparity highlights the need to consider the integrated response of the hydrologic system when evaluating impacts from disturbance and making comparisons between settings.