Nautical Chart Analysis: SF Bay

Nautical Chart Analysis: SF Bay

Integrated Science 1Name:Period:

 Background

In order to best understand the science of the San Francisco Bay estuary, it is important to develop an accurate and detailed understanding of the physical (or abiotic) factors that operate in this ecosystem. The National Oceanic and Atmospheric Administration (a federal government agency) produces and regularly updates maps (nautical charts) for navigable waters under their jurisdiction. These charts provide a wealth of information on the physical factors of the bay that you will need to know and understand. Nautical charts are produced for marine navigation. They contain information on all navigational aids, such as buoys and beacons, lighthouses, radio and radar stations, shipping channels, restricted areas. Water depths are recorded as soundings, in meters, feet or fathoms. Near-shore depths are shown by contours and layered tints. In addition, physical features such as shorelines, shallows, reefs, submerged rocks, shipwrecks, kelp beds, ocean bottom sediments, are shown in detail.

 Procedure

You will work in teams to make a detailed analysis of one section of the SF Bay Estuary. The four sections of the bay to be studied are: South Bay, Entrance to SF Bay (Central Bay), San Pablo Bay, and Suisun Bay. After you have completed your work on one section of SF Bay you will share your data with other groups. Likewise, other groups will share their data with you.

 Data

A. Map Overview

1.Which of the four sections listed above are you studying?

2.Using the map scale on the map itself and a ruler, what is the scale of the map in nautical miles? (1 nautical mile = 1.852 Km = 1 minute of latitude)

* cm = 1 nautical mile

3.What are the latitude and longitude ranges defining your study area (in degrees and minutes. Remember that there are 60 minutes per degree)?

*latitude: distance in degrees and minutes either north or south of the equator

*longitude: the distance in degrees and minutes either east of west of the prime meridian

Latitude at the top part of your study area:  minutesN

At the bottom part of your study area:  minutesN

Longitude at the left part of your study area:  minutesW

At the right part of your study area:  minutesW

B. Bay Overview (shared data)

5.How wide is widest part of the bay in your study area (coastline to coastline in any straight-line direction)? Record in centimeters and convert to nautical miles. Use your answer to #2 and show your work.

______cm______nm

6.How narrow is the narrowest part of the bay in your study area (coastline to coastline in any straight-line direction)? Record in centimeters and convert to nautical miles. Show your work.

______cm______nm

7.What is the deepest point in your study area? *remember that deep = white on a nautical chart

How deep is it? (feet)

Where is it?

8.Where is the shallowest point in your study area? *remember that shallow = dark blue on a nautical chart

How deep is it? (feet)

Where is it?

9.What is the average depth of your area? (Randomly select ten depth-sounding points and find their average depth). show your work – listing all 10 data points – to include your deepest and most shallow points. Box your final answer.

10.How many rivers and creeks bring freshwater to your study area? List them.

*Summarize questions 5-10 in data table 1. Have one group member record data on overhead projector when complete.

Data Table 1

C. Bay and Surrounding Land Information

11.List two cities in your study area.

12.List three land points in your study area (hint: “point” or “pt” is in the name!)

13.List four islands located in your study area.

14.List three locations that a vessel with a 35-foot draft (goes 35 ft. into the water) could dock in your study area. (hint: the depth at the shoreline would be 36 feet or greater)

 Discussion and Conclusion – Answer in Complete Sentences!

1.Describe at least three natural processes that occur on a regular basis to change the shape and depth of the San

Francisco Bay.

2.Describe at least three possible human impacts in your study area.

3.Using the information in Data Table 1, of all of the study sites, where do you expect pollution to have a more lasting effect? Explain your answer.

Of all the study sites, where do you expect pollution to have the least lasting effect? Explain your answer.

4. Describe what would happen to the plants, animals, shape of the land, etc. if freshwater inflow to your study areawas reduced by 50%.

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Nautical Map Activity