Oct 26 Lecture: Groundwater and Water Quality Flashcards
subsurface subsidence=
the sinking of the ground
- may result from excessive loss of groundwater
compaction=
the compression of aquifer material faced with loss of water results in a decrease in permeability and porosity
- this material cannot recharge to the same extent
in coastal regions, excessive withdrawal can lead to a ___ ___ into the fresh waters of an aquifer
saltwater intrusion
fresh water is ___ dense than salt water, so they stay ____
less
unmixed
what are 2 methods to artificially enhance recharge?
- build recharge basins (retention ponds)
- any way of slowing down runoff (which increases surface water infiltration)
groundwater may ___ large volumes of soluble rock
- what does this cause?
dissolve
collapse of subsurface rock= sinkholes
- caverns may also be enlarged
karst=
a type of landform associated with many sinkholes in soluble bedrock (like limestone, dolomite, or gypsum)
stalactites =
formations in caves formed by water dripping, then evaporating and leaving behind these icicle-shaped formations (they hang from the ceiling of a cave)
if you suck water out from areas with a coal aquifer, the water will have little ___ and high ___
- why is this?
low oxygen, high iron
coal uses the oxygen, the water reacts with the air to produce iron in the water
TDS=
total dissolved solids
- the sum of dissolved solids in the water
hard water contains
why?
substantial amounts of calcium and magnesium
- due to dissolution of carbonate rocks in an aquifer
hard water reacts poorly with ___ and can leave behind ___ ___ in plumbing/ appliances
soaps
mineral deposits
adverse effects of calcium carbonate (from limestone) in concentrations over the TDS limit?
likely no adverse effects
adverse effects of uranium above TDS limit?
can concentrate in human tissue and cause issues- should be limited to concentrations lower than the TDS criteria
