Spring 2000   Quiz 1a

A wave with a period T=6.4 seconds, a deep water height Ho=1.3 m, and a deep water angle of attack ao=0° moves into water with depth D= 3.1 m.  You will do all calculations at this new depth and not deep water.

Quiz 1 b differed only in the numbers above.

(7) Calculate the speed and wavelength of the wave at this depth (not in deep water).

(2) Determine if the wave is deep, shallow or intermediate at this depth. (Method counts)

(2) What will be the height of the wave at this depth (not in deep water)?

(2) Will the have broken before it reaches this depth? (Method counts)

1a version:

Given:  T=  6.40 sec        Ho=  1.30 m   then at  d=  3.10 m

Lo= 1.56 * T^2=   63.90 m        Co= Lo/T = 1.56 * T =    9.98 m/sec

d / Lo =   0.0485

d/L       d/Lo      tanh    H/Ho(Ks)

Table values:  0.0925    0.0484    0.5240    1.0280

L=   33.51 m   &  C=    5.24 m/sec using L= d / (d/L) & C = L/T

L=   33.48 m   &  C=    5.23 m/sec using L = Lo * tanh & C=L/T

H= Ks * Ho =  1.34 m   (if no refraction)

H/d=    0.43

Breaks:  FALSE   (if H/D > 0.78)

1b version:

Given:  T=  7.10 sec        Ho=  1.40 m   then at  d=  3.90 m

Lo= 1.56 * T^2=   78.64 m        Co= Lo/T = 1.56 * T =   11.08 m/sec

d / Lo =   0.0496

d/L       d/Lo      tanh    H/Ho(Ks)

Table values:  0.0925    0.0484    0.5240    1.0280

L=   42.16 m   &  C=    5.94 m/sec using L= d / (d/L) & C = L/T

L=   41.21 m   &  C=    5.80 m/sec using L = Lo * tanh & C=L/T

H= Ks * Ho =  1.44 m   (if no refraction)

H/d=    0.37

Breaks:  FALSE   (if H/D > 0.78)

(3) What variables are included in the wave climate, and why are these particular variables important?

(4)  In the coastal classification scheme recommended by the textbook, what at the categories of coastline and what differentiates them?

Spring 2000   Quiz 2a

A wave with a period T=7.3 seconds, a deep water height Ho=1.6 m, and a deep water angle of attack ao=27° moves into water with depth D= 2.8 m.  You will do all calculations at this new depth and not deep water.

(5) Calculate the speed and wavelength of the wave at this depth (not in deep water).

(3) By how much will the wave have refracted when it reaches this depth?

(3) What will be the height of the wave at this depth (not in deep water)?

(3) What determines whether a beach will be composed on black volcanic sand rather than quartz?

(3) What are the three categories in a sediment budget, and give an important example in each category.

(3) How is the last ice age currently affecting sea level?  Are the changes isostatic or eustatic?

Spring 2000   Quiz 2b

A wave with a period T=7.6 seconds, a deep water height Ho=1.8 m, and a deep water angle of attack ao=31° moves into water with depth D= 4.2 m.  You will do all calculations at this new depth and not deep water.

(5) Calculate the speed and wavelength of the wave at this depth (not in deep water).

(3) By how much will the wave have refracted when it reaches this depth?

(3) What will be the height of the wave at this depth (not in deep water)?

(3) What determines whether a beach will be composed on white calcite rather than quartz?

(3) What are the three categories in a sediment budget, and give an important example in each category.

(3) How is the last ice age currently affecting sea level?  Are the changes isostatic or eustatic?

Quiz 2a

Given:  T=  7.30 sec        Ho=  1.60 m     &   Alpha-o=  27.0ø

then at  d=  2.80 m

Lo= 1.56 * T^2=   83.13 m        Co= Lo/T = 1.56 * T =   11.39 m/sec

d / Lo =   0.0337

d/L       d/Lo      tanh    H/Ho(Ks)

Table values:  0.0750    0.0329    0.4390    1.1050

L=   37.33 m   &  C=    5.11 m/sec using L= d / (d/L) & C = L/T

L=   36.50 m   &  C=    5.00 m/sec using L = Lo * tanh & C=L/T

H= Ks * Ho =  1.77 m   (if no refraction)

alpha1=   11.76  using alpha = arcsin( C / Co * sin(alphao))

alpha1=   11.50  using alpha = arcsin(tanh * sin(alphao))

Kr=    0.95 using Kr=sqrt(cos(alphao)/cos(alpha))

H =    1.69 m    using Ho*Kr*Ks

H/d=    0.60

Breaks:  FALSE   (if H/D > 0.78)

Quiz 2b

Given:  T=  7.60 sec        Ho=  1.80 m    &   Alpha-o=  31.0ø

then at  d=  4.20 m

Lo= 1.56 * T^2=   90.11 m        Co= Lo/T = 1.56 * T =   11.86 m/sec

d / Lo =   0.0466

d/L       d/Lo      tanh    H/Ho(Ks)

Table values:  0.0900    0.0461    0.5120    1.0370

L=   46.67 m   &  C=    6.14 m/sec using L= d / (d/L) & C = L/T

L=   46.13 m   &  C=    6.07 m/sec using L = Lo * tanh & C=L/T

H= Ks * Ho =  1.87 m   (if no refraction)

alpha1=   15.47  using alpha = arcsin( C / Co * sin(alphao))

alpha1=   15.29  using alpha = arcsin(tanh * sin(alphao))

Kr=    0.94 using Kr=sqrt(cos(alphao)/cos(alpha))

H =    1.76 m    using Ho*Kr*Ks

H/d=    0.42

Breaks:  FALSE   (if H/D > 0.78)

Spring 2000   Quiz 3a

(4) Briefly discuss three conditions that would lead to multiple bars:

(4) What are the key variables in the Longuet-Higgins equation, and how do they affect the calculated result?

(4) What is the relationship between wave size, sediment size, and beach slope?

(4) Sketch the general mathematical shape of most beach profiles, and highlight two key characteristics of your sketch.

(4) Define the following terms:

• Basal shear stress:
• Rip current:

Spring 2000   Quiz 3b

(4) Briefly discuss three conditions that would lead to the absence of bars:

(4) What are the key variables in the Longuet-Higgins equation, and how do they affect the calculated result?

(4) What is the relationship between wave size, sediment size, and beach slope?

(4) Where will rip currents be located--be specific.

(4) Define the following terms:

• Basal shear stress:
• Closure depth:

Spring 2000   Quiz 4a

Phi     =-log2(Dia mm/1mm)

logx(a) = logy(a)/ logy(x)

(Mean - Median) / Std Dev

Normal Distribution: 1 s from Mean at 16% and 84%

(2)  Convert 0.45 mm to Phi units

(2)  Convert -3.45 Phi to mm:

(3) Briefly discuss the range of options available in dealing with coastal erosion problems.

(3)  This is figure 9-2 of the text.  What does it show and why did the author include it?

(2) What is the name and scaling on the vertical axis on this graph?

(2) Why are the solid horizontal lines located where they are on this graph?

(4) What are the two parameters that define a log-normal distribution, and how does each affect a graph?

(2) Where does the largest sand plot on the horizontal axis?

(2) What is the name and scaling on the vertical axis on this graph?

(2) Why are the solid horizontal lines located where they are on this graph?

(4) What are the two parameters that define a log-normal distribution, and how does each affect a graph?

(2) When does the largest sand plot on the horizontal axis?