Groundwater Flow to Wells Flashcards
water wells are used for extraction of water to fill ___, ____, ____, and ____ needs
domestic, industrial, municipal, and irrigation
an alternative way of collecting water through manual operation to move groundwater from the aquifer up to the surface
jetmatic pump
wells also function to ____ into the ground
inject fluids
example of how wells function to inject fluids
injection of hazardous material, provided that there is an impermeable layer
as means of groundwater management, wells sometimes use ______ at rates greater than natural recharge
artificially recharge aquifers
during well pumpage, ____ of the head in the aquifer around the well occurs
drawdown
during ____, there is increase in the head of the aquifer
injection
what is a drawdonw?
a change in the hydraulic head of an aquifer around a well due to pumping as part of an aquifer test or well test
is the change in the hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test
drawdown
a pumping cone, or ____, will form in the aquifer around a ______ as the water level _____
cone of depression
pumping well
declines
in _____, the head is constant with time, no cone of depression
steady state flow
in this flow regime, flow is in the horizontal radial direction
radial flow
direction of the flow in radial flow
horizontal radial direction
radial flow exist in the time period before the _____ has reached the _____ of the reservoir, also known as _____ period
pressure transient
boundaries
infinite-acting time period
t or f: radial flow is often observed following other flow regimes
T
emergence of radial flow in an infinite conductivity hydraulically fractured well
linear-fracture flow to radial flow
1 cubic feet is equal to how how many gal
7.48
how many minutes in 1 day
1440
discharge causes decline in the cone of depression, or ____
drawdown
recharge causes _____ of the cone of deppression
buildup
t or f: cone of depression declines as hydraulic head decreases during pumpage
T
t or f: even if the cones of depression of nearby wells are already intersecting, you can still extract groundwater
f (you can not)
the distance from the land surface (or the measuring point) to the water in the well under non-pumping (static) conditions
static water level
how is an aquifer test done?
done by constantly stimulating the aquifer through constant pumping and observing the aquifer’s “response” (drawdown) in observation wells
aquifer test is a common tool that hydrogeologist use to characterize a system of ____, _____, and ____
system of aquifers, aquitards, and flow system boundaries
is a particular type of aquifer test where water is quickly added or removed from a groundwater well, and the change in hydraulic head is monitored through time, to determine near well aquifer characteristics
Slug test
slug test is also known as
bail-down test
a cylinder that is heavier than the water, which causes displacement of water equal to its volume when dropped into the well
slug
explain the slug test
- a slug is dropped into a well which cause water in an equal volume of the slug to be displaced
- the water head rises, causing the flow to increase, and eventually water level slowly drops
- water level eventually reaches the head of the aquifer, the rate of dropping of water level decreases because of the decline in gradient
- water level reaches initial head, slug is taken out, water level becomes so low
- well is recharged again as water from the aquifer flows into the well again
initiated by rapidly lowering the water level in the control well and then taking measurements of the rising water level in the well, slug is withdrawn
rising-head test
rising-head test is also known as
slug-out test
is conducted by rapidly raising the water level in the control well and subsequently measuring the falling water level.
falling-head test
falling-head test is also known as
slug-in test
boundaries are considered to be either ____ or ____
recharge or barrier boundaries
is a region in which aquifer is replenished
recharge boundary
is an edge of the aquifer, where it terminates by either thinning, abutting a low permeability formation, or has been eroded away
barrier boundary
much of water sources in the philippines is dependent on
surface water
artificially recharge aquifers is the artificial injection of
surface water
one example of injection of fluids into the well
storing hazardous material, must have impermeable confining layer
an inverted cone is created in the head of the aquifer during
injection
how is water pumped up with oil and returned to the ground
- oil and water pumped up together into oil wells
- separators separate oil from water, sand, and other naturally occurring materials
- produced water with oil removed is injected back onto the geologic zone from which it oroginated
t or f: steady state flow still creates cone of depression
F (it doesn’t)
radial flow is created by _____ which results in _____ pressure
pumping out of water
negative
1 cubic feet is equal to how many cubic meter
0.028
1 gal is equal to how many cubic meter
0.0045
aquifer tests determine what
near surface aquifer characteristics
how many hours should a pumping test be conducted
24-48 hours
t or f : if the rate of the pumping test is constant, the aquifer is sustainable. if there is changes, it may not sustain
T
a slug test is a particular type of aquifer test where groundwater is being quickly _____ or ____
added or removed
two types of barrier boundary
bounded by stream on one side
bounded by an impermeable boundary on one side
what is perennial stream
have water all year round
what is intermittent stream
water is dependent on groundwater baseflow
what is ephemeral stream
water during/after precipitation
t or f: it is difficult to delineate boundary through ocular investigation
T
t or f: aquifer thickness should be very large compared to resultant drawdown near real well
T
delineating hydrogeologic boundaries needs ______ and _____ methods
geophysical and dating
