Long-term trends in groundwater recharge and discharge in a fractured bedrock aquifer – past and future conditions

Figures & data

Figure 1. (a) Location of the study area (Covey Hill Natural Laboratory). The Hemmingford (HMG) weather station is shown on the inset map; (b) regional cross-section. Note that the delineated “watershed limits” correspond to the gauging station watersheds. The Système d'information hydrogéologique (SIH) wells are not represented in this figure. Modified with permission from Levinson et al. (2014b).

Table 1. RCM runs used for this study (see Mearns et al. 2012 for model acronym details).

RCM	GCM	Member	Domain	Emissions scenario
CRCM4.2.3	CGCM3	5	AMNO	A2
CRCM4.2.3	CGCM3	2	AMNO	A2
CRCM4.2.3	ECHAM5	1	AMNO	A2
CRCM4.2.3	ECHAM5	2	AMNO	A2
CRCM4.2.3	Arpège UnifS2	–	AMNO	A1B
CRCM4.2.0	CGCM3	4	AMNO	A2
HRM3	HADCM3	–	QC	A2
CRCM	CCSM	–	N. Amer.	A2
ECP2	GFDL	–	N. Amer.	A2
RCM3	CGCM3	–	N. Amer.	A2

Notes:

RCM, Regional Climate Model; GCM, General Circulation Model; CRCM, Canadian Regional Climate Model version; CGCM3, Coupled Global Climate Model version 3; ECHAM5, Max Planck Institute for Meteorology Global Climate Model version 5; AMNO, North America; Arpège UnifS2, France National Centre for Meteorological Research Global Circulation Model; HRM3, Hadley Center Regional Model version 3; HADCM3, Hadley Center Coupled Model version 3; QC, Quebec; CCSM, Community System Climate Model; N. Amer., North America; ECP2, Experimental Climate Prediction Center Regional Spectral Model; GFDL, Geophysical Fluid Dynamics Laboratory; RCM3, Regional Climate Model version 3.

Figure 2. The groundwater model domain with recharge and hydraulic conductivity zones (from Levison et al. 2014b). Recharge zone 1 covers the area of the peatland.

Figure 3. Comparison of Poirier et al. (2014) data with measured data from the Hemmingford (HMG) weather station from 1961 to 2010: (a) monthly temperature, and (b) monthly precipitation. Error bars represent minimum and maximum monthly values over the 1961–2010 period. CEHQ = Centre d'expertise hydrique du Québec.

Figure 4. Annual vertical inflow (VI), evapotranspiration (PET), net precipitation (P_net), P_net 10-year moving average and temperature (T) from 1900 to 2010.

Figure 5. Annual recharge from 1900 to 2010 compared to (a) average simulated hydraulic heads for the study area, (b) average simulated spring flow and (c) average simulated baseflows for the Allen River, the Outardes River and the Schulman stream.

Table 2. Long-term trends for calculated recharge and for simulated heads, spring flows and river/stream baseflows.

	Trends 1900–2010
	1900–1965	1966–2010
Recharge (m)	↓^*
	↓^*	null
Heads (m)	↓^*
	↓^*	↑
Spring flow (m^3/s)	↓^*
	↓^*	↑
Baseflow – Allen River (m^3/s)	↓^*
	↓^*	↑
Baseflow – Outardes River (m^3/s)	↓^*
	↓^*	↑
Baseflow – Schulman stream (m^3/s)	↓^*
	↓^*	↑

^* Statistically significant results.

Table 3. Groundwater flow simulations with climate change scenarios. Future projections for calculated recharge and for simulated heads, spring flows and river/stream baseflows.

	Climate scenario
	REF	FUT
Average annual recharge (mm)	128	136^*
Average heads for the entire study domain (m)	176.5	177.3^*
Average spring flow (m^3/s)	0.0011	0.0013^*
Average baseflow – Allen River (m^3/s)	0.094	0.103^*
Average baseflow – Outardes River (m^3/s)	0.074	0.083^*
Average baseflow – Schulman Stream (m^3/s)	0.014	0.016^*

Notes:

REF, reference period; FUT, future period.

^* Statistically significant results for the ensemble mean.

Figure 6. Comparison with climate change conditions for: (a) recharge, (b) average hydraulic heads, (c) total spring outflows, (d) baseflows to the Allen River, (e) baseflows to the Outardes River and (f) baseflows to the Schulman stream. The significant differences (Wilcoxon–Mann–Whitney test; α = 0.05) between the reference and future periods are marked with *. OBSERVED is the simulation using the observed climate data, ENS MEAN is the ensemble mean, REF is the reference period and FUT is the future period. The 1st, 25th 50th 75th and 99th percentiles are plotted.

Levison, J., M. Larocque, V. Fournier, S. Gagné, S. Pellerin, and M. A. Ouellet. 2014b. Dynamics of a headwater system and peatland under current conditions and with climate change. Hydrological Processes 28: 4808–4822.

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