Post on 25-Feb-2016
description
Gaining vs. losing streams
Source: U.S.G.S.
Source: U.S.G.S.
Effects of pumping on GW - surface water interaction
Schematic showing basic elements of an unconfined aquifer system
Source: U.S.G.S.
Example of a perched water table and its relationship to the regional unconfined aquifer system
Layered aquifer system(s), showing confined aquifer beneath an unconfined aquifer. Note the artesian conditions in the valley.
Aquifer in fractured volcanic rocks (Kona, HI)
Source: U.S.G.S. National Groundwater Atlas
Regional aquifers in the Mid-Atlantic U.S.
Source: U.S.G.S. National Groundwater Atlas
Fractured limestone and metamorphic rock
Unconsolidated sediments & sedimentary rock
Locations of major sandstone aquifers in the U.S.
Source: U.S.G.S.
Example showing porosity (note that for illustration purposes, the sand grains are shown to be unrealistically far apart)
Types of porosity
Example showing porosity in a thin section of sandstone
Hydrostatic Head: An Example...
Which way does the groundwater flow?
10 m
3 m
0 m
What is the head at each point?
10 m
A
B
C
Pressure head = 7 mElevation Head = 3 mTotal Head = 10 m
3 m
0 m
What is the head at each point?
10 m
A
B
C
Pressure head = ?? mElevation Head = ?? mTotal Head = ?? m 3 m
0 m
What is the head at each point?
10 m
A
B
C
Pressure head = 0 mElevation Head = 10 mTotal Head = 10 m
3 m
0 m