groundwater and karst key terms

groundwater

freshwater that is stored underground

aquifer

storage system for groundwater

porous

has a lot of pore space and ability to hold water 

permeable 

water can move through easily 

hydraulic conductivity

measures porosity, permeability, and properties of fluid to determine if a source is good for water storage/transport 

potable water

water that is safe to drink

vadose/unsaturated zone

zone where pore space is filled with mostly air and some water

saturated zone

zone where pore space is completely filled with water 

water table

line that divides the saturated and unsaturated zones 

confining layer 

layer that prevents water from moving in/out of aquifers 

aquiclude

type of confined aquifer, water cannot get in/out

aquitard

type of confined aquifer, water can get in slowly

potentiometric surface

area where water rises when a well is drilled in due to high pressure, don’t have to pump water 

springs 

areas where groundwater intersects the surface 

artesian/flowing wells

a well where water rises to the surface without pumping 

gaining stream

streams where the water table intersects with the stream bed 

losing stream

streams where the water table is below the stream bed

hydrograph

charts that show changes in the water table over time 

darcy’s law

equation that describes the flow of liquid through a porous medium

drawdown

water table lowering from groundwater extraction

cone of depression

area where water table lowers surrounding a groundwater extraction site 

recharge 

rate at which groundwater is replenished 

discharge

rate at which groundwater is extracted

groundwater mining

over-extraction of groundwater 

pore pressure

pressure that comes from the weight of overlying water, keeps aquifers stable

subsidence

land surface down-warping due to rapid groundwater removal

point source pollution

pollution that has one defined source

non-point source pollution

pollution that doesn’t have a defined source or has multiple sources 

superfund site

water area that has federal support to clean up

remediation

making polluted groundwater suitable for human use again

karst 

system of above and below ground features that are produced by bedrock being dissolved by water/acid

limestone

type of rock that makes up karst systems due to high solubility 

disappearing streams

streams that “disappear” under a wall of rock and turn into an underground karst system 

calcite

mineral that makes up limestone, easily dissolved

tufa

calcite/water deposit that forms in lakes/streams

travertine

calcite/water deposit that forms in hot springs/caves

cave

a natural cavity, recess, or chamber formed beneath the surface by dissolved bedrock

speleothem

structure in caves made of mineral deposits from water reacting with calcite 

stalacties

speleothems that hang on the celing

stalagmites

speleothems that grow up from the floor

sinkhole

funnel/bowl shaped depression that comes from the dissolution of underlying bedrock/sediment 

soda straw

the thin starting of speleothems

column

speleothems that connect from floor to ceiling 

dissolution

the dissolving of something

underground streams

streams that flow underground through karst systems 

cave spring

area where underground streams emerge