AIM

1
Recharge to a Fractured Bedrock Aquifer ? Tay
River Watershed, Perth, ON Claire A. Milloy
Kent S. Novakowski Department of Civil
Engineering, Queens University, Kingston, ON
FIELD SITE METHODS
RESULTS CONCLUSIONS
INTRODUCTION

• Site characterization developed from
• bedrock and overburden geological maps
• air percussion drilling of four, six inch
  boreholes
• pumping straddle packer slug testing
• GPS topographic survey
• borehole camera survey
• sustained hydraulic head measurements

• Fractured bedrock aquifers are typically
  characterized, studied and managed with the
  scientific knowledge and modeling tools developed
  for porous media flow and transport.
• Water supply issues and concern for contaminant
  transport have encouraged
• the need to develop the expertise and tools to
  address regional scale fracture-specific bedrock
  flow and transport and surface water to
  groundwater interactions
• Recharge to crystalline bedrock groundwater
  systems is currently considered to be governed by
• Local , intermediate and regional surface and
  bedrock topography
• Surface water body interactions
• Distribution of hydraulic conductivities as per
  fracture orientation, densities, connectivity and
  effective permeability
• Lateral and vertical distribution of overburden
• Land use classification etc.

Rita
Katrina
Individual rainfall events
Tay River
Katrina
Rita
Regional response?
Figure 1 Well completion details
transmissivities from hydraulic testing
Figure 2 Field site schematic well locations
local hydraulic gradient
AIM
Rita
Katrina

• A test site has been developed adjacent to the
  Tay River in a small hay field south-west of
  Perth, ON
• Aim
• To characterize the local groundwater flow system
• Qualify and quantify infiltrating precipitation
  to discrete fracture zones as a means of
  assessing recharge
• Establish a comprehensive data set for
  calibration of a surface to groundwater model
  HydroSphere (University of Waterloo and Laval)
• Component of Tay River Pilot Project
• Aims to develop scientific understanding and the
  tools necessary for complete regional assessments
  of fractured bedrock watersheds for the health
  and sustainability of the potable water supply

• Horizontal field gradient changes over summer
  with natural regional water table decline in
  response to the maintained water levels near Tay
  River
• rapid changes in vertical and horizontal (field
  scale) hydraulic gradient during rainfall events
• Extreme response to intense rainfall events in
  shallow bedrock fracture zones air entrapment
  exaggerating water level rise?
• Discharging at local shallow sinks?
• Immediate but dampened response in deeper bedrock
  zones
• a regional response?

• Recharge to discrete fracture zones estimated
  from.
• continuous hydraulic head measurements
• dedicated pressure transducers installed at each
  hydraulically discrete fracture zone
• rainfall and ongoing meteorological data
  collection
• eight inch tipping bucket rain gauge
• weather station with onboard data-logging
  capabilities
• six inch tipping bucket rain gauge
• affixed sensors
• relative humidity, barometric pressure,
  temperature and wind