EAS 201: Lecture 14
February 6, 2019
• Lecture notes borrowed from Karlis Muehlenbachs’ slides February 6, 2019.
• Flood Characteristics:
o Stage – the height of the river/body of water (volume).
▪ Flood Stage – when stream exceeds bank height.
o Crest – the maximum stage that is reached.
o Upstream Flood – occurs in smaller, localized upper part of basin.
o Downstream Flood – larger, lower part of drainage basin.
o Flash Flood – is a type of upstream flood from a rapid rise of stream stage.
o Image taken from Karlis Muehlenbachs’ slides
February 6, 2019 →
o Canada example – “Ice Jam” (ice creates a sort
of dam, potential for sudden increase in river
levels both above/below ice jam).
• Hydrographs – measure amount of water/stage of
river as a function of time.
• Water Table – area at upper level of zone of
o Where pores & fractures of ground are
saturated w/ water.
• Springs – where water table intersects surface, usually
bounded below by aquicludes/aquitards.
o Aquitard: an impermeable layer under ground that water will accumulate above.
o Aquiclude: solid, impermeable area underlying/overlying an aquifer.
• Porosity – portion of void space in a given material where fluid(s) can be stored.
• Permeability – measures how readily a fluid will pass through a material.
o Igneous, metamorphic, and chemical sedimentary rocks have low permeability &
porosity (crystals are tightly interlocked).
o Clastic sediments have higher porosity & permeability.
▪ Sandstones are very porous; clay & mud rich rocks are not porous or
• Aquifer Geometry: