Hydro 3

Question 1

What are the two general types of slug test?

Answer 1

Rising head tests and falling head test

Question 2

What type(s) of slug test work well in a confined aquifer?

Answer 2

Both rising head and falling head test work well in a confined aquifer

Question 3

What type(s) of slug test work well in an unconfined aquifer?

Answer 3

Rising head test are good but falling head test are not accurate?

Question 4

Why are falling head test in an unconfined aquifer not accurate?

Answer 4

It overestimates K because water flows into unsaturated zones

Question 5

When would you use Hvorslev’s Method?

Answer 5

Would use in an unconfined aquifer, partially penetrating well

Question 6

What is the relationship between screen length and well radius for Hvorslev Method?

Answer 6

Screen length is greater than 8 times the well radius

Question 7

When can Brown & Rice Method be used?

Answer 7

Confined or unconfined, fully or partially penetrating

Question 8

Effective Radius

Answer 8

Radius from which water in aquifer flows to the well.

Question 9

In steady flow for a confined aquifer, how does the hydraulic gradient behave?

Answer 9

The gradient of the water table is not constant, it increases in the direction of flow

Question 10

When is equilibrium achieved?

Answer 10

When the cone of depression has reached a source and the recharge rate equals the pumping rate.

Question 11

Steady State Conditions

Answer 11

Recharge rate equals pumpage.

Question 12

In steady state flow, what is constant with time?

Answer 12

The head is constant with time

Question 13

Unsteady Flow

Answer 13

Flow in which the head changes with time.

Question 14

When a well is in a completely confined aquifer, where does the water come from?

Answer 14

The elastic or specific storage of an aquifer.

Question 15

For a confined aquifer, what values of storativity are typically observed?

Answer 15

Typically 0.005 or less

Question 16

When may a water table divide be present?

Answer 16

When an aquifer is subject to infiltration.

Question 17

What represents discharge per unit width?

Answer 17

qx’

Question 18

What does (w) represent in equations for steady state flow unconfined aquifer.

Answer 18

The recharge rate. The net addition or loss of water, most commonly due to ET. Th

Question 19

If w represents ET, what kind of value will it have?

Answer 19

A negative value.

Question 20

What is qx’ at a water table divide?

Answer 20

0

Question 21

What assumptions are made when studying transient effects in an unconfined aquifer?

Answer 21

The aquifer is confined top and bottom, there is no source of recharge to the aquifer, the water is compressible and water is released instantaneously from the aquifer as the head is lowered, the well is pumped at a constant rate.

Question 22

What happens to the cone of depression in steady state conditions?

Answer 22

The cone of depression stays constant

Question 23

What happens to the cone of depression in transient conditions?

Answer 23

The cone of depression keeps growing

Question 24

When would the Theis equation be used?

Answer 24

Unsteady flow with information about the aquifer

Question 25

Theis equation (format 1)

Answer 25

h1-h=(Q/4piT)int(from u to infinity) (e^(-a)/a)da, where U=r^2S/(4Tt)

Question 26

Theis Equation (format 2)

Answer 26

h1-h=(Q/(4piT))W(u)

Question 27

Thiem equation Confined

Answer 27

T=Q/(2pi(h2-h1))ln(r2/r1)

Question 28

Thiem equation Unconfined

Answer 28

K=Q/(pi(b2^2-b1^2))ln(r2/r1)

Question 29

When can you use Thiems solution to predict drawdown in a well itself?

Answer 29

If pumping is 100% effective

Question 30

What are the assumptions using Nueman's Method?

Answer 30

* Aquifer is unconfined, * non-steady state, * dados zone doesn't influence drawdown, * Water initially pumped comes from instantaneous release of water from elastic storage, * eventually water comes storage due to gravity drainage of aquifer pores, * Drawdown is negligible compared to sat. thickness, * The aquifer may be - but doesn't have to be - anisotropic with radial hydraulic conductivity different than horizontal conductivity

Question 31

What methods can be used for leaky confining aquifers

Answer 31

Walton Method, Hantush Inflection Method, Hantush/Walton Method

Question 32

Overdampened

Answer 32

Water recovers to the initial static level in a smooth manner

Question 33

Underdampened

Answer 33

Water socialites about the static water level with magnitude of oscillation decreasing with time.

Question 34

When is under dampening most likely to occur?

Answer 34

In screens wells that have a long water column and wells that are screened in a highly transmissive layer.

Question 35

What defines Le in high k?

Answer 35

The screen

Question 36

What defined Le in low K?

Answer 36

The filter pack

Question 37

What kind of materials are slugs made of?

Answer 37

Teflon, steel, or PVC