Estimating deep recharge rates beneath an interlobate moraine using temperature logs.
The Sandilands area of southeastern Manitoba contains an interlobate moraine that is a major ground water recharge area. Underlying the highly permeable sediments of the moraine are up to 100 m of till and the subcrop of the Winnipeg Formation, which contains a major sandstone aquifer. Ground water flow within the till is examined using high-resolution temperature profiles and solutions to the differential equation for heat flow in porous media. These analyses indicate that recharge to the sandstone aquifer is occurring at a rate of approximately 2 x 10(-8) m/sec beneath the moraine, which is in agreement with recharge rates determined by conventional ground water hydraulics (10(-7) to 10(-10)(m/sec) and another study using multiple environmental tracers (1 x 10(-9) to 6 X 10(-9) m/sec). The use of temperature to determine ground water flux is not limited by half-lives as many environmental tracers are, and this allows for cost-effective estimation of recharge and discharge rates over longer periods.
D003362:Cost-Benefit Analysis; D004784:Environmental Monitoring / Q000191:economics / Q000379:methods*; D019015:Geologic Sediments; D055593:Geological Phenomena; D005844:Geology; D006207:Half-Life; D008350:Manitoba; D010539:Permeability; D013696:Temperature; D014872:Water Movements