aquifers Flashcards
what are aquifers
natural underground water stores
how do aquifers form
long time
water infiltrates porous rock and fills pore spaces
what happens if overused
collapse ground
turn saline as seawater can infiltrate rocks
where is ogallala aquifer
north america
across 8 states including colorado, texas, kansas etc
beneath great plains
what is the ogallala aquifer
shallow water table aquifer
surrounded by sand silt clay gravel
why aquifer in those rocks
porous
water can infiltrate
eroded material from The Rocky Mountains and rainfall produced this aquifer
what is ogalla rock type
sedimentary
sandstone, gravel, quartz
what is happening to ogallala
reducing in size
some places already gone
in 50 years expected 70% depleted
1940 water level fell 100ft due to introduction large scale irrigation
why is this happening to ogallala
large demand for irrigation water due to recurring drought
95% of use of this aquifer for irrigation
farmers pumping out faster than restored by precipitation (essentially non renewable)
+ golf course irrigation
why is it bad what is happening to ogallala
supplies water to 1/5 US agricultural harvest
could cause ground collapse
could become saline
where are the major aquifers and what type
africa
middle east
australia
fossil aquifers (old and not been replenished)
what happened to many aquifers
exploited for unsustainable irrigation
become saline
