Modeled impacts of predicted climate change on recharge and groundwater levels

Abstract

[1] A methodology is developed for linking climate models and groundwater models to investigate future impacts of climate change on groundwater resources. An unconfined aquifer, situated near Grand Forks in south central British Columbia, Canada, is used to test the methodology. Climate change scenarios from the Canadian Global Coupled Model 1 (CGCM1) model runs are downscaled to local conditions using Statistical Downscaling Model (SDSM), and the change factors are extracted and applied in LARS-WG stochastic weather generator and then input to the recharge model. The recharge model simulated the direct recharge to the aquifer from infiltration of precipitation and consisted of spatially distributed recharge zones, represented in the Hydrologic Evaluation of Landfill Performance (HELP) hydrologic model linked to a geographic information system (GIS). A three-dimensional transient groundwater flow model, implemented in MODFLOW, is then used to simulate four climate scenarios in 1-year runs (1961-1999 present, 2010-2039, 2040-2069, and 2070-2099) and compare groundwater levels to present. The effect of spatial distribution of recharge on groundwater levels, compared to that of a single uniform recharge zone, is much larger than that of temporal variation in recharge, compared to a mean annual recharge representation. The predicted future climate for the Grand Forks area from the downscaled CGCM1 model will result in more recharge to the unconfined aquifer from spring to the summer season. However, the overall effect of recharge on the water balance is small because of dominant river-aquifer interactions and river water recharge.

A watershed-scale study of climate change impacts on groundwater recharge (Annapolis Valley, Nova Scotia, Canada)

“…The potential effects of climate change on aquifer recharge have been studied with various models in different regions across Canada and for various periods, producing a wide range of results (e.g. Chen et al 2004, Scibek and Allen 2006, Jyrkama and Sykes 2007.…”

Linking Climate Change and Groundwater

“…The complexity of approaches for obtaining the climate data series appears to have increased in recent years, ranging from the use of global averages (Loaiciga et al 1996;Zektser and Loaiciga 1993) to the use of regional "bulk" projections (Allen et al 2004;Brouyere et al 2004;Vaccaro 1992;Yusoff et al 2002) to the direct application of downscaled climate data (Jyrkama and Sykes 2007;Scibek and Allen 2006b;Scibek et al 2007;Serrat-Capdevila et al 2007;Toews and Allen 2009) to the use of regional climate models (Rivard et al 2008;van Roosmalen et al 2007van Roosmalen et al , 2009). Some of the early efforts to assess potential hydrologic impacts were reviewed by Gleik (1986).…”

“…Thus, most studies develop watershed or smaller scale models, which are better constrained by available data and, thus, more easily calibrated. However, there remain challenges for coupling GCM predictions with hydrological models (Scibek and Allen 2006b;Toews and Allen 2009;Xu 1999), including issues discussed in the section Global Climate Projection.…”

Response of a fractured bedrock aquifer to recharge from heavy rainfall events

“…Moreover, most studies on the impacts of climate change on recharge have focused on changes in total annual or monthly precipitation (Appaih-Adjei, 2006;Scibek and Allen, 2006;Toews and Allen, 2009;Jyrkama and Sykes, 2007); few have considered how shifts in the frequency and magnitude of events could influence groundwater aquifers (Taylor et al, 2013b;Owor et al, 2009;Mileham et al, 2009). …”