Questions for Voyage 6

Real-time Questions

Instructions: Choose the phrase that best answers each question.

1. Examine Figure 1A (8-9 August) and Figure 1B (1-2 August). Which statement best describes the tidal levels (number of feet above MLLW and number of feet
below MLLW) in the two figures?

A. The lowest tidal level was on 8-9 August and the highest tidal level was on 1-2 August.

B. The highest tidal level was on 8-9 August and the lowest tidal level was on 1-2 August.

C. The highest and lowest tidal levels were both on 8-9 August.

D. The highest and lowest tidal levels were both on 1-2 August.

2. Examine Figure 2. The depth range in San Francisco Bay is 0-100 meters. In Figure 2, depths of 0-5 meters are shown in greenish-blue colors; depths of 5-70 meters are shown in progressively deeper shades of blue; and depths of 70-100 meters are shown in magenta (purple color). Land above water is shown in black. Which part of the Bay is deepest?

A. Golden Gate (entrance to the Bay from the ocean in the Central Bay block)

B. San Pablo Bay (north of the Central Bay block)

C. Suisun Bay (east of San Pablo Bay)

D. South SF Bay (south of the Central Bay block)

3. Examine Figure 3A. At 9:36 on August 5, the tide was rising. Look at the orange/green line (predicted and actual sea levels). The water elevation at 9:36 was about

A. 0 feet

B. 2 feet

C. 4 feet

D. 6 feet

4. Examine Figure 3B. At 9:00 on August 5, the tide was rising and currents were moving water from the ocean into the Bay. Which statement best describes the variation in current speed within the Bay?

A. The currents move faster in deeper water.

B. The currents move faster in shallow water.

C. There is no correlation between depth and current speed.

5. Compare Figures 3B and 4B, the current maps generated for rising and falling parts of the tidal cycle on August 5. Based on these maps, tidal currents inside the Bay on August 5 were strongest (longest arrows) during

A. the rising tide (flood current shown in Figure 3B).

B. the falling tide (ebb current shown on Figure 4B).

Lag-time Questions

Instructions: Write short answers for the following questions. Answers will be graded credit / no credit. Results will be available several days after the exercise due date.

1. Examine Figures 1A and 1B. What is the maximum tidal range (that is, the difference in elevation between the highest and lowest tidal levels of the day) in Figure 1A?
[Note that when the elevation is below 0 you must add the elevation below 0 to the elevation above 0.] What is the maximum tidal range in Figure 1B?

2. Examine Figure 2. Describe the depth variations in San Francisco Bay. Where are the areas of greatest depth and the areas of least depth?

3. Examine Figure 3B. Describe the direction and speed of the current during the flooding part of the tidal cycle. How does the direction and speed change as the current
flows progessively further into the Bay?

4. Examine Figures 3A and 4A. What do you think happened to the direction and speed of the tidal current at the Golden Gate just before noon, between the times of Figure 3A and 4A?

5. Answer the following questions based on your journey to the SFPORTS real-time site. What is the day and time? What is the elevation of the tide? Is the tide rising (flooding current), falling (ebbing current), or slack (no current)?

NOTE: if you cannot access the SFPORTS web site, go to the tidal charts in today's newspaper or to the first web site listed in the voyage credits, where you can get tidal information for any location.

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