Groundwater flow paths Flashcards
What is an equipotential?
equipotential is an imaginary line (usually drawn on a cross-section or plan view) where all points have the same flow potential (hydraulic head), you move up or down one of the lines the pressure head and elevation head will increase and decrease proportionally to give you the same hydralic head.
Water will cross equipotential lines at what angle?
right angles
If the equipotential lines are tightly packed what does that mean for the hydraulic gradient? How will water flow?
The hydraulic gradient will be very steep and water flow will be faster
Under what conditions can we reliably draw streamlines between equipotentials?
if the aquifer is isotropic and homogeneous
What does it mean for the aquifer to be homogenous?
If hydraulic conductivity (K) is the same at all points, the medium is homogenous
What does it mean for the aquifer to be isotropic?
If hydraulic conductivity (K) is the same in all directions, the medium is isotropic
What are discharge areas?
Valleys, groundwater comes out of here
What are recharge areas?
Hills, groundwater gets filled through here
What does a fast flow path look like?
the flow path is short
What does a slow flow path look like?
the flow path is long
What are the three scales of groundwater systems?
can be local, intermediate, or regional
How do you determine the age of groundwater?
Use protium, deuterium, and tritium (showed up in bomb testing so useful for dating less than 60 years old groundwater)to date groundwater, can also use 14C, in atmosphere 14C made goes into groundwater, as groundwater goes undergound the 14 C begins to decay and you can use it for dating groundwater up to 50,000 years. Can also use CFCs which can dissolve in groundwater and can be used to measure.
What is baseflow versus event flow?
Baseflow is a consistent contributon to the river that groundwater can contribute to, event flow is when there’s a big rain event causing the fast flow pathway water to be pushed up (through changing equipotential lines) and causes the groundwater to contribute to surface water.
Lakes, rivers, and wetlands are typically situated where?
At groundwater discharge points
Is groundwater flow 3d or 2d?
3d
