Characterization of a Regional Aquifer System in the Maritimes Basin, Eastern Canada

Abstract

A regional hydrogeological study was carried out in the Maritimes provinces, in one of the main aquifer systems in Canada. The study area covers a land surface of 10,500 km 2 , of which 9,400 km 2 is over Carboniferous and younger rocks. The sedimentary fractured bedrock is composed of a sequence of discontinuous strata of highly variable hydraulic properties, and is overlain by a thin layer of glacial till (mostly 4 to 8 m). Depending on areas, 46 to 100% of the population relies on groundwater for water supply. Almost all residential wells are shallow (28 m on average) open holes that are cased only through the surficial sediments. This paper describes a regional hydrogeological investigation based on targeted fieldwork, the integration of a wide variety of existing multisource datasets and groundwater flow numerical modelling. The aim of this paper is to present the current state of understanding of the aquifer system in a representative area of the Maritimes Basin, along with the methodology used to characterize and analyze its distinct behaviour at the regional, local and point scales. This regional hydrogeological system contains confined and unconfined zones, and its aquifer lenticular strata extend only a few kilometers. Preferential groundwater recharge occurs where sandy tills are present. The estimated mean annual recharge rate to the bedrock aquifers ranges between 130 and 165 mm/year. Several geological formations of this Basin provide good aquifers, with hydraulic conductivity in the range of 5×10 −6 to 10 −4 m/s. Based on numerical flow modelling, faults were interpreted to play a key role in the regional flow. Pumping test results revealed that the aquifers can locally be very heterogeneous and anisotropic, but behave similarly to porous media. Work performed at the local scale indicated that most water-producing fractures generally have a sub-horizontal dip along a north-east (45°) strike.

Controls on Nitrate Loading and Implications for BMPs Under Intensive Potato Production Systems in Prince Edward Island, Canada

“…The bedrock is intensely to very intensely fractured (Figure B) and vertical fractures are present in addition to the dominant bedding (horizontal) fractures. Previous studies in PEI show that the aquifer is strongly anisotropic (Lajtai and Stringer ; Francis ; Rivard et al ), with the north‐eastern trending of the dominant sub‐horizontal fractures imparting a quasi horizontal two‐dimensional flow, with a preferential component along the trend.…”

“…In the aquifer, laboratory measurements of matrix hydraulic conductivity on cores from Harrington Farm averaged 10 −7 m/s, a value typical for PEI sandstone bedrock (Carr ; Francis ). In contrast, bulk hydraulic conductivity obtained through pumping tests ranged from 10 −6 to 10 −4 m/s (Carr ; Lapcevic and Novakowski ; Rivard et al ). This indicates that the flow in the aquifer is controlled primarily by the fractures rather than the matrix.…”

“…Based on several studies involving stream hydrograph separation, water table level fluctuations, water balance, and numerical modeling (e.g., Francis ; Rivard et al ; Danielescu et al ), groundwater recharge was estimated in the range of 300 to 500 mm. This is consistent with the expectation that recharge in PEI represents 30 to 40% of annual precipitation (Jiang et al ; PEI DELJ ).…”

Submarine groundwater discharge (SGWD): an unseen yet potentially important coastal phenomenon in Canada

“…9 Hydraulic head map of the bedrock aquifers of Maritimes Basin, Eastern Canada. Arrows indicate general groundwater flow directions (Rivard et al 2008) Canada ( Fig. 9) are cited Rivard et al (2008); but overall, it appears from the lack of available references in the literature that saltwater intrusion is not currently a widespread issue in Canada.…”

Application of GWQI to Assess Effect of Land Use Change on Groundwater Quality in Lower Shiwaliks of Punjab: Remote Sensing and GIS Based Approach

“…Soltan (1999) used WQI to indicate the quality of groundwater from ten wells located near the Dakhla Oasis in the Western Egypt. Many studies (Kim 2009;Babiker et al 2007;Rivard et al 2008) have been done on a regional scale with respect to groundwater quality and quantity. Remote sensing, because of its spatial and temporal coverage capabilities (Andreae 2002), has been important tool for studying Land Use Land Cover (LULC) changes (Anderson et al 1976;Rasch 1994;Green et al 1994;Kam 1995;Carlson and Azofeifa 1999;Luque 2000;Maselk et al 2000;Yang and Lo 2002;Guerschman et al 2003;Rogana and Chen 2004;Zsuzsanna et al 2005).…”