Boss Point Formation fractured bedrock aquifer

Hydrogeological Context

Version	Metadata
	f64ad8c6-548f-4f2a-927d-a28f36a47c67

Project
Carboniferous Basin

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Boss Point Formation fractured bedrock aquifer unit description

Update:2014-02-04

Physiography
In ascending order, the geological groups are: basement complex and Horton, Windsor, Mabou Groups, and Boss Point Formation. The internal stratigraphy of these units is complex and often laterally discontinuous. The Boss Point formation is mainly composed of sandstone, siltstone and mudstone. It is covered with a sandy matrix till unit. This till feature involves high hydraulic conductivity, suggesting a good percolation of surface water. Considering that the hydrogeological unit also has a good hydraulic conductivity, the recharge rates of the Boss Point formation are the most important in the region. The unit also shows one of the most important aquifer potential of the area. Groundwater flows in the rock through fractures and interconnected pores between grains. Since the fractures have a much higher permeability than the surrounding matrix, the water flows essentially in the fractures. Groundwater flow mainly follows the surface topography. Considering the weak protection provided by the till, the aquifer is vulnerable to contamination from surface. The groundwater quality is good, but the area near the Petitcodiac River has some local problems of fluoride, iron, manganese and pH.
Hydrogeological region	Maritime Bassin
Hydrogeological context
Relief	The average altitude of the Boss Point formation is 50-100 m. The edge of the Northumberland Strait and Bay of Fundy are lower altitudes (0-50 m). They increase near Caledonian mountains to reach 300-350 m. This area includes many moderate slopes (10-15%), while in others the slopes are less present. The terrain is relatively flat.
Area	1034.00 km2
Lithology
Description	In ascending order, the geological groups are: basement complex and Horton, Windsor, Mabou Groups, and Boss Point Formation. The internal stratigraphy of these units is complex and often laterally discontinuous. The Horton Group consists of a sequence of sedimentary and volcanic rocks that is overlain by the marine limestone and evaporates strata of the Windsor Group. The marine beds are overlain by thick assemblages of continental origin, which correspond to the Riversdale-Mabou group and Boss Point formation. This formation is mainly composed of sandstone, siltstone and mudstone. The sedimentary rocks are covered by a till unit which extends over the entire area. Some colluvium and rock outcrops are also found in Boss Point formation.
Source
Aquifer
Aquifers	List of aquifers Boss Point rock aquifer

Unit properties

Bedrock aquifer media


Typical value:	porous - fractured
Description	Groundwater circulates within the rock through fractures and interconnected pore spaces between the individual grains. Since fractures have a much higher permeability than the matrix around them, groundwater flows predominantly through fractures.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Confinement

Typical value:	semi confined - unconfined
Description	The system can be considered semi-confined, but confined and unconfined conditions can be found, mainly depending on the till layer composition. Considering the till unit is sandy, the confinement is less important for this hydrogeological unit than for the others.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Surficial sediment thickness

Description	In New Brunswick, the till thickness varies between 0-20 m. The average thickness is 8 m for New Brunswick and Nova Scotia.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Well depth
35 m Range: [0 to 94.5] m
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Groundwater depth
4.8 m Range: [0 to 40.8] m
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Surficial unit hydraulic conductivity
0.0000013 m/s
Description	Boss Point is one of the formations exhibiting the largest hydraulic conductivity values.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Bedrock hydraulic conductivity
Range: [1e-06 to 5e-05] m/s
Description	The hydraulic conductivity is above 1E-6 m/s and below 5E-5 m/s
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Regional precipitation
1108 mm/y Range: [983 to 1376] mm/y
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Regional evapotranspiration
Range: [345 to 440] mm/y
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Regional recharge
310 mm/y
Description	Boss point is the most important recharge area of the region.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Hydrogeological unit potential

Typical value:	Good or variable potential
Description	The aquifer potential is variable. The unit is one of the main aquifer in the area.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Aquifer vulnerability

Typical value:	High
Description	Boss Point formation is one of the most vulnerable in the region due to sandy composition of the till causing less protection.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin

Groundwater Quality

Description	Groundwater quality is good. The area near Petitcodiac River shows some local problems of fluoride, iron, manganese and pH.
Source	Hydrogeological Atlas of South-Central Area of the Maritimes Carboniferous Basin