Earth Science

Assignment #4, Name _________________________

(40 points) Due Monday October 5

Water and the making of sedimentary rock

1. Argue: Why is surface water both a creator and destroyer of sedimentary rock? Give both sides of the argument . 2 points





2. Distinguish between soil moisture and groundwater. What divides the two? 2 points







3. In city #1, the tombstones are all readable back to the year 1880. In city #2, the same types of tombstones are only readable back to 1940; the older ones are blurred out. Why might that be? (2 pts)








4. To measure the porosity, we start with 200 ml of water and after we saturated the soil sample, we had 120 ml left. The total volume of saturated soil is measured to be 200 ml. What is the porosity? (2 pts)








Assignment #4, page 2 Name _________________________


5. PG County Soil Inspector 6 points

You are investigating soil samples to understand water quality in PG County.

Your measurements are given below. Answer the following:

a. What might you conclude about the Largo 2 soil sample?





b. Which might be gravel? Why?





c. Which has the highest permeability? Which has the 2nd highest? What is the major difference between these two- what might that suggest about the composition of the soil (refer to class notes)?




Unknown soil Porosity Water flow time for 200 ml of water Water retention
Largo 1 20% 10 minutes 30 ml
Largo 2 15% 2 hours 35 ml
Waldorf 50% 10 seconds 5 ml
Mitchelville 45% 25 seconds 20 ml


Assignment #4, page 3 Name _________________________


2. Watershed practice 6 points

Below is a map of the area near Tranquility Pond (the blue). Use it to complete the following.

a. Outline on the map below the complete Serenity Stream watershed


b. Label the head (H) and mouth (M) of Serenity Stream

c. With a colored pencil (just make the line thick), color the tributaries of Harmony Creek

d. With a dashed line, mark the drainage divide between the Harmony Creek

and Serenity Stream watersheds.



















Assignment #4, page 4 Name _________________________


3. Home Research: Follow the Water! (12 points + 2 for extra credit)

Overall Objective: Describe where your home lies in the Chesapeake Bay Watershed and the path that water takes from your home to the Bay. To fulfill this objective, answer the 3 following questions (use a separate piece or pieces of paper- think of this as a mini-report)

1. As a first step, what is your main watershed (i.e. which main river basin do you live in). It will probably be either the Potomac or Patuxent. Which?


2. Where are you in this watershed? Which sub-watershed? For example, PGCC is in the Western Branch sub-watershed of the Patuxent.



3. How does water from your immediate residential area get into the sub-watershed? What creeks does it follow? What tributaries of the sub-watershed? You will need to look for storm drainages and creeks like we will in class. Some may be not named- that’s OK, provided you document your efforts to try and find them. And for some of you it will be easier or harder than others; I will take this into account in grading.


For full credit, you need to include a map of your local area with key streams/tributaries labeled to show your local watershed. Otherwise I won’t know how you got your answers. If I don’t understand your explanation, you will lose credit.


There are many Internet resources which can help, but there is no one best answer- you will have to do some research. You will certainly need Google Maps to locate your place of residence. Zooming in and out will give you both your immediate neighborhood and the larger area. See what streams and rivers are labeled. This can often get you most of the way.

Try googling sites such as the Chesapeake Bay Foundation, ( or just google “Chesapeake Bay Watershed” or “Prince George’s County Watershed”. Or google specific river names like “Anacostia” or “Potomac” or “Patuxent” and see what maps come up. Or look at Wikipedia entries for specific rivers.

In class, we will go over the PGCC watershed as an example.


EXTRA CREDIT: 2 points. Include a photograph of a stream in your sub-watershed which illustrates either erosion or deposition. Must be specific and clear as to where this is and what is occurring in the photograph. A vague photo of a pretty stream will not do.

Assignment #4, page 5 Name _________________________


4. Organizations that deal with your local watershed (8 points)

a. Investigate local organizations (either government or university-related or private) that deal with your local watershed (somewhere in the Chesapeake Bay Watershed). Easiest way to start is to Google

“Chesapeake Bay conservation organizations”

b. Pick one organization and write a paragraph on their goals and methods. You must cite the web site you used! Why did you pick this group?

c. Discuss a project they are currently involved in. (another paragraph). Examples could be either science-related, political action related, or social outreach related or a combination. You must say which category or categories this project belongs to! What are the challenges they face?

Note: the expectation is that you will have two well-thought-out paragraphs- keep the total less than 1 page! (I won’t read more!)

How do I grade writing?

¼ grammar: subject-verb-object: coherent sentences; spelling/typos?

¼ organization of paragraph: intro sentence describes what you will discuss, concluding sentence provides some sort of summary or assessment.

¼ content: Are you using your own words, or copying a web page

¼ explanation: can I understand what you are saying? Are you giving examples to help your explanation?


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