An investigation of groundwater and surface water interactions near a small stream in Prince Edward Island
University of New Brunswick
The province of Prince Edward Island (PEI) currently has a moratorium on the installation of high-capacity irrigation water supply wells, mainly due to concerns over potential interactions with nearby streams. The focus of this research was to conduct an investigation near a small stream in Maple Plains, PEI, and to assess the potential for the site to be used for stream depletion related research. The objectives were to determine whether the stream was gaining or losing, to establish the natural hydraulic gradients, and to characterize the overburden materials. Stream discharge measurements made in September 2016 indicated that the stream was neither gaining nor losing water. Water elevation data from five drive-point piezometers, two groundwater monitoring wells, an unused residential well, and the stream, revealed that there was an unsaturated zone between the stream and aquifer. The identification of this unsaturated zone only proves that the stream was not directly connected to the underlying aquifer, and does not prove disconnection. The groundwater elevation data also provide evidence that groundwater naturally flows in the same direction as the stream. Soil samples collected during monitoring well installation showed that there is roughly 3 m of a sand phase till overlying the fractured sandstone aquifer. The hydraulic conductivity of the till appears to decrease with depth. This is also supported by the presence of a perched groundwater system that develops during periods of increased infiltration.