EESC07H3 Lecture Notes - Lecture 6: Oxbow Lake, Active Channel, Aquifer
13 Feb 2018
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Document Summary
Dowsing/water witching: using bent sticks to find water to put a well. This only works because they have preconceived knowledge about the hydrogeological environment (i. e. fracture patterns). This week: we are focusing on unlithified sediment (wind blown sediment, alluvial plains). These deposits have the potential to accumulate to great thicknesses (100s to 1000s of meters). K values are very variable, clays: 10-9 cm/s vs. gravels 10-1 cm/s. Due to their bedded character, they are strongly anisotropic (klateral > kvertical) sometimes by. Porosities tend to be high due to the lack of cementation. Secondary (i. e. through fractures) k/n (permeability/porosity) is a minor consideration. These sediments are deposited by flowing water. Hydrogeological conditions will depend on the energy of the sedimentary environment: high energy streams deposit coarse materials, low energy streams deposit finer grained materials. Braided river environments (steep gradients): fining upwards sequence, coarse material gets deposited first and then it fines upwards.
