Shifting Hydrological Processes in a Canadian Agroforested Catchment due to a Warmer and Wetter Climate

Abstract

This study examines the hydrological sensitivity of an agroforested catchment to changes in temperature and precipitation. A physically based hydrological model was created using the Cold Regions Hydrological Modelling platform to simulate the hydrological processes over 23 years in the Acadie River Catchment in southern Québec. The observed air temperature and precipitation were perturbed linearly based on existing climate change projections, with warming of up to 8 • C and an increase in total precipitation up to 20%. The results show that warming causes a decrease in blowing snow transport and sublimation losses from blowing snow, canopy-intercepted snowfall and the snowpack. Decreasing blowing snow transport leads to reduced spatial variability in peak snow water equivalent (SWE) and a more synchronized snow cover depletion across the catchment. A 20% increase in precipitation is not sufficient to counteract the decline in annual peak SWE caused by a 1 • C warming. On the other hand, peak spring streamflow increases by 7% and occurs 20 days earlier with a 1 • C warming and a 20% increase in precipitation. However, when warming exceeds 1.5 • C, the catchment becomes more rainfall dominated and the peak flow and its timing follows the rainfall rather than snowmelt regime. Results from this study can be used for sustainable farming development and planning in regions with hydroclimatic characteristics similar to the Acadie River Catchment, where climate change may have a significant impact on the dominating hydrological processes.Water 2020, 12, 739 2 of 29 controlled by snow processes that are expected to be particularly sensitive to climate change [7][8][9][10][11][12][13][14]. Changes to snow accumulation and melt are expected to modify the timing, duration and magnitude of streamflow in the mid-latitudes of the Northern Hemisphere [15], which could redefine flooding risks as well as hydrological services, such as water supply from snowmelt runoff. The interactions between snow and vegetation play a significant role in snow accumulation [16,17], which can influence runoff volumes and timing. Snowfall intercepted by vegetation can increase sublimation losses, depending on tree species, canopy structure as well as atmospheric conditions [18,19]. Once on the ground, snow can be redistributed by wind, particularly in open and wind-exposed environments, which increases sublimation losses from blowing snow [20,21]. Snow is typically transported from sparsely vegetated and exposed terrains to densely vegetated areas and/or topographic depressions [22,23].The traditional approach to assess climate change impact on hydrology is a "top-down" approach, where one or several hydrological models are forced by climate change scenarios from Global Circulation Models (GCMs) [24]. The spatially coarse outputs of GCMs (approximately 150-300 km) are downscaled to represent local climate conditions required by hydrological models, using either statistical or dynamical downscaling approaches [25]. Statistical downscaling relies on...

Topographic and vegetation controls of the spatial distribution of snow depth in agro-forested environments by UAV-lidar

“…However, if canals and forest edge snow depths are discarded, agro-forested snow depth maps illustrate somewhat similar phenomena to Aygün et al (2020), where snow depths in the exposed field appear to be slightly lower than those in the forest. Clusters of high snow depth values in the central area of the Saint-Maurice field in Fig.…”

“…The main objective of this paper is to study the small-scale spatial variability of snow depth by UAV-lidar and investigate the terrain and vegetation controls on this snow depth heterogeneity in an agro-forested and a boreal landscape. The study sites are based in southern Québec, Canada, where forests intertwined with mosaics of open agricultural fields in low-lying lands (agro-forested landscapes) play a significant role in altering the spatial distribution of the snow cover (Aygün et al, 2020).…”

Mass balance modelling and climate sensitivity of Saskatchewan Glacier, western Canada

“…a -1 within a single scenario. This illustrates the usefulness of scenario-free response surfaces to assess glacier mass balance sensitivity to climate as a background to evolving climate projections (Aygün et al, 2020;Prudhomme et al, 2010). Nontheless, given the current ensemble climate scenarios the (static) mass balance could decrease by -0.5 to -2.0 m w.e a -1 by the mid-century, and by -0.5 to -4 m w.e a -1 by the end of the century, relative to baseline conditions (Ba = -0.68 m w.e.…”

“…The DEBAM model was run 81 times for every combination of ΔTa and ΔP perturbation imposed on the Ta and P records over the 30-year reference period 1981-2010. Changes in mass balance for each sensitivity run were plotted as response surfaces, which provide a simple way to assess climate sensitivity across a range of possible climate change scenarios (e.g Aygün et al, 2020;Prudhomme et al, 2010)…”

Sensitivities of Hydrological Processes to Climate Changes in a Central Asian Glacierized Basin

“…The increment ranges of temperature and precipitation in basins that are of interest were informed from projections of assembles of climate models (Rasouli et al, 2014). Advantages of using the incremental climate scenarios include to test how specific hydrological processes are sensitive to changes of temperature and precipitation (Aygün et al, 2020), and to reveal to what extent the effects of temperature changes on specific hydrological characteristics can be compensated by the effects of precipitation changes. This method is suitable to the investigation of hydrological responses to climate changes in small basins (Rasouli et al, 2015).…”