Hydrogeology and hydrogeochemistry of the Chaudière River watershed aquifers, Québec, Canada

Figures & data

Figure 1. (a) Chaudière River watershed with a digital elevation model as background. The Appalachian Piedmont extends northward and the Appalachian Uplands southward from the marine limit. Locations of major municipalities are indicated with white circles; surface water bodies are shown (the same applies for the following figure parts). (b) Simplified tectonostratigraphic units (modified from Slivitzky and St-Julien 1987). (c) Simplified Quaternary geology (modified from Caron 2012). (d) Regional potentiometric surface. Black dots indicate measured groundwater levels.

Figure 2. Statistical analysis of hydraulic conductivity values. The box extends from the lower (Q_25%) to upper quartile (Q_75%) with a median line; whiskers extend to the most extreme values within a range equal to 1.5 × (Q_75% – Q_25%); numbers in parentheses indicate the total number of data points per bedrock unit.

Table 1. Hydrogeologic properties of soil units used in recharge simulations.

Soil type	Total porosity (%)	Hydraulic conductivity (m/s)
Organic	0.9	3×10^−5
Sands	0.32	1×10^−4
Clays	0.45	1×10^−9
Gravels	0.40	3×10^−3
Reworked till	0.45	1×10^−4
Shallow till	0.45	1×10^−4
Till	0.45	1~3×10^−8

Figure 3. Spatial distribution of the annual recharge rate predicted with the Hydrologic Evaluation of Landfill Performance (HELP) model, together with the locations of gauging and weather stations.

Table 2. Statistical information on chemical analyses of 155 groundwater samples collected in bedrock and surficial wells.

Parameter	Retained drinking	Bedrock wells (n = 123)				Surface wells (n = 32)
	water criterion	min	max	median	# of exc.	min	max	median	# of exc.
Temperature (°C)	15^(1)	7.2	12.1	8.5	0	7.9	15.5	10.55	1
pH	6.5–8.5^(3)	5.78	9.59	7.52	19	5.9	7.91	6.57	14
Specific conductance (μS/cm)	-	0.2	1656	244.1	0	31.3	515	140.2	0
Dissolved oxygen (mg/L)	-	0	13.1	1.305	0	0.2	10.69	5.66	0
Ca (mg/L)	-	0.08	160	51	0	5.3	100	23.5	0
Mg (mg/L)	-	0.02	19	6.5	0	0.84	20	2.5	0
Na (mg/L)	200^(1)	1.3	290	9.8	1	0.79	70	3.1	0
K (mg/L)	-	0.18	16	0.72	0	0.16	18	0.595	0
Total alkalinity (mg CaCO3/L)	-	14	330	136.25	0	12	290	55.5	0
Cl (mg/L)	250^(1)	0.21	415	7.1	2	0.335	180	4.55	0
SO4 (mg/L)	500^(1)	1.8	95	18	0	0.6	76	10	0
Hardness (mg CaCO3/L)	200^(1)	0	445	152	33	17	295	80	5
Total dissolved solids – TDS (mg/L)	500^(1)	43	1210	288	14	31	563	137	1
Total cyanides (mg/L)	0.2^(3)	0.004	0.004	0.004	0	0.004	0.004	0.004	0
DIC (mg C/L)	-	11	89	34	0	6.6	70	17	0
DOC (mg C/L)	-	0.2	7.1	0.74	0	0.2	23	0.885	0
F (mg/L)	1.5^(3)	0.03	1.9	0.015	2	0.03	0.19	0.015	0
S (mg/L)	0.05^(1)	0.02	2.9	0.01	10	0.02	0.4	0.01	2
NH4^+ (mg N/L)	-	0.01	1.8	0.03	0	0.01	3.4	0.01	0
NO2-NO3 (mg N/L)	10^(3)	0.02	14	0.055	1	0.02	4.2	0.45	0
Total N (mg N/L)	-	0.02	13	0.29	0	0.12	7.4	0.92	0
Total inorganic P (mg/L)	-	0.03	0.4	0.015	0	0.03	0.03	0.015	0
P (mg/L)	-	0,002	0,38	0,0054	0	0,002	0,12	0,003	0
Al (μg/L)	100^(2)	0.2	22	3.5	0	0.55	150	4.1	1
Ag (μg/L)	-	0.001	0.006	0.001	0	0.001	0.03	0.001	0
As (μg/L)	10^(3)	0.03	14	0.48	3	0.05	2.1	0.17	0
B (μg/L)	5000^(3)	1.7	590	9.1	0	1.2	200	4.85	0
Ba (μg/L)	1000^(3)	0.054	860	53	0	1.5	3600	13.55	1
Be (μg/L)	-	0.004	0.12	0.002	0	0.004	0.2	0.002	0
Br (μg/L)	-	3.5	300	14	0	0.5	130	7.6	0
Cd (μg/L)	5^(3)	0.004	0.3	0.006	0	0.004	0.096	0.007	0
Cr (μg/L)	50^(3)	0.04	0.4	0.02	0	0.04	1.7	0.0795	0
Co (μg/L)	-	0.007	2.5	0.088	0	0.017	3.2	0.0495	0
Cu (μg/L)	1000^(3)	0.05	68	0.78	0	0.12	150	5.85	0
Fe (μg/L)	300^(1)	0.05	16000	16	15	0.05	32000	3.25	3
I (μg/L)	-	0.5	82	1.8	0	0.5	20	0.635	0
Li (μg/L)	-	0.18	130	4.4	0	0.06	30	1.04	0
Mn (μg/L)	50^(1)	0.027	2300	88	69	0.038	1200	1.28	5
Hg (μg/L)	1^(3)	0.01	0.18	0.005	0	0.01	0.12	0.005	0
Mo (μg/L)	-	0.021	16	0.62	0	0.014	1.1	0.0885	0
Ni (μg/L)	-	0.02	24	0.38	0	0.09	9.9	0.59	0
Pd (μg/L)	-	0.005	0.023	0.0025	0	0.005	0.0096	0.0025	0
Pt (μg/L)	-	0.006	0.003	0.003	0	0.006	0.003	0.003	0
Pb (μg/L)	10^(3)	0.03	1.2	0.054	0	0.03	1.2	0.19	0
Sb (μg/L)	6^(3)	0.004	8.6	0.027	1	0.004	0.097	0.0185	0
Se (μg/L)	10^(3)	0.3	2.6	0.15	0	0.3	1.5	0.15	0
Si (mg/L)	-	2.7	9	5.6	0	0.003	8	4.3	0
Sn (μg/L)	-	0.01	0.046	0.005	0	0.01	0.042	0.005	0
Sr (μg/L)	-	1.1	4300	470	0	32	2600	165	0
Tl (μg/L)	-	0.005	0.068	0.0025	0	0.005	0.035	0.0025	0
U (μg/L)	20^(3)	0.0047	8.2	0.56	0	0.003	1.5	0.0595	0
V (μg/L)	-	0.01	2.2	0.029	0	0.01	6.5	0.0395	0
Zn (μg/L)	5^(1)	0.7	1300	2.7	0	0.7	110	3.7	0
Total coliforms (UFC/100mL)	10^(3)	0	160	4	52	0	160	45	23
E. coli (UFC/100mL)	0^(3)	0	37	0	11	0	80	0	6

⁽¹⁾ Health Canada Aesthetic criteria;

⁽²⁾ Health Canada Operational guidance values;

⁽³⁾ MDDEFP; Non-regulated parameters are indicated with “-”; TDS and hardness are computed values; parameters in exceedence are indicated in bold.

Figure 4. Water types in bedrock (n = 113) and surficial (n = 31) wells. Water samples from surficial wells are indicated with a black dot in the center. Ion concentrations are scaled to the observed total dissolved solids (TDS).

Figure 5. Spatial distribution of groundwater types, location of geochemical cross-section along with groundwater samples used for isotope analyses (indicated with numbers from 1 to 10), and location of precipitation gauges. Water samples from surficial wells are indicated with a black dot in the center. Numbers in parentheses indicate number of samples per water type (bedrock well, surficial well).

Figure 6. Relationship between bromine (Br) and chlorine (Cl) concentrations.

Figure 7. Isotopic signatures of the monthly precipitation water samples collected from the two stations [P1 at ~500 m above sea level (asl) and P2 at ~70 m asl] and 10 water samples from bedrock wells (indicated in Figure 8). Straight lines indicate published meteoric water lines at the regional scale.

Figure 8. (a) Conceptual groundwater flow model along a regional flowpath indicated with cross-section A–A’ in Figure 5. (b) Concentrations of major hydrochemical constituents. (c) Relationship between tritium and radiocarbon age. Linear regressions are given with bold lines.

Slivitzky, A., and P. St-Julien. 1987. Compilation de la région de l’Estrie-Beauce. Rapport MM 85-04. Ministère de l’Énergie et des Ressources du Québec, QC.

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Caron, O. 2012. Synthèse et modèle cartographique 3D des Dépôts Quaternaires pour les Bassins-Versants des Rivières Chaudière et Saint-François: Géochronologie, Sédimentologie et Paléogéographie Wisconsinienne du sud du Québec. PhD diss., Université du Québec à Montréal.

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