I am psting this question in two parts........ cn someone answer for me. Costlin

Question

I am psting this question in two parts........ cn someone answer for me.

Costline application.

Many Hazard City residents have purchased second homes, cottages, or timeshares near the beach. The most popular locations for these purchases are along the ocean beachfront. Potential buyers must be cautious when purchasing properties close to a beach because shoreline erosion can be a significant problem. Therefore, the most prudent buyers seek professional advice before they commit to such an important purchase.

Shoreline erosion is a significant problem, and each year it destroys or damages millions of dollars' worth of property. However, those who are well informed about how erosion occurs are usually willing to research the history of a property and can generally determine if it is at risk. In an effort to minimize such risks for their clients, a Hazard City real estate office has asked you to assess a few properties and report on how they might be affected by shoreline erosion.

Assessment of shoreline property must begin with knowledge of the forces at work: When assessing shoreline-erosion risk, you must keep in mind that moving water will always carry as much sediment as its velocity will allow. The faster the water’s velocity, the more sediment (and larger sediment particles) it can carry. Longshore current occurs when waves approach a beach at an angle. The waves retreat perpendicular to the shoreline, and so sediment is transported along the shoreline. Shoreline protection devices such as groins, rip-rap, and breakwaters disrupt the longshore current’s ability to transport material.

To complete your work, you will use the links on the left, which will help you

·         Understand that shorelines are dynamic locations with erosion and deposition working to alter the landscape;

·         Have some knowledge of shoreline erosion, sediment budgets, and streambank erosion; and

·         Understand the principles that are used to determine if a shoreline property has an erosion hazard.

Part D - Breakwaters and beaches

Breakwaters are constructed to protect a portion of beach from wave action. Over time, how might breakwaters become obsolete (essentially, no londer be needed) for a section of beach?

Choose from part 1, 2, 3, 4.

1. Breakwaters could not become obsolete due to regular beach activity.

2. The sand could build up behind the breakwater so much that the beach connects with the breakwater.

3. The breakwaters could cause storms to slow down just over the protected beach and preferentially destroy any ships moored there.

4. So much erosion could eventually occur downcurrent from the breakwater that the protected beach would be exposed.

Part E - Rivers and beaches

The Clearwater River reaches the ocean just north of this beach. How might damming the Clearwater River affect beach dynamics?

Choose from part 1, 2, 3, 4.

1. Damming the river would decrease the amount of sediment reaching the beach and cause the beach to shrink.

2. Damming the river would have no effect on the beach, since rivers do not carry sediment.

3. Damming the river would have no effect on the beach, since beaches are formed due to wave action.

4. Damming the river would increase the amount of sediment reaching the beach and cause the beach to grow.

Part F - Picnicking at the river

You are taking your family for a picnic along Muskett River. As you are trying to determine where to picnic, your priority is to place your family on the side of the river where the water is moving the slowest. Where should you set up your picnic?

Choose from part 1, 2, 3, 4.

1. On the opposite side of the river from a point bar

2. Along a straight portion of the river

3. At a point bar

4. It doesn't matter; all the water moves at the same velocity.

Part G - Placing rip-rap in a river

Riprap can reduce the velocity (hence the energy and carrying capacity) of the water in the river. How might placing a rip-rap along a streambank affect the beach where the stream meets the ocean?

Choose from part 1, 2, 3, 4.

1. More deposition could occur, because the stream will preferentially drop its sediment at the rip-rap.

2. The rip-rap will cause the water to slow down when it reaches the ocean, causing more erosion at the beach.

3. More erosion could occur, because the stream is carrying less sediment for its velocity than it should.

4. Rip-rap along a stream will not affect the beach, because the two are not related.

Part H - Erosion rates

The Island Migration Case Study shows how Brown's Island in the Ohio River has migrated over time. The original map was published in 1954. The photo revision took place in 1983 and showed that the northern end of the island had eroded 5 feet (60 inches) over that time. At what rate was the northern end of Brown's Island eroding during that period?

Choose from part 1, 2, 3, 4.

1. approximately 5 feet/year

2. approximately 2.5 feet/year

3. approximately .5 inches/year

4. approximately 2 inches/year

Part I - Erosion of Brown’s Island

If Brown's Island were migrating at 1 foot/year, how long would it take to erode the entire length of the island?

Choose from part 1, 2, 3, 4.

1. almost 13,000 years

2. not more than 200 years

3. over 20,000 years

4. between 900 and 1000 years

Part J - Erosion of Clayton Point

At what rate did the northern side of Clayton Point (Site 2) erode between the two maps provided?

Choose from part 1, 2, 3, 4.

1. between 6 and 7 feet/year

2. over 20 feet/year

3. less than 5 feet/year

4. between 90 and 100 feet/year

1. Breakwaters could not become obsolete due to regular beach activity.

2. The sand could build up behind the breakwater so much that the beach connects with the breakwater.

3. The breakwaters could cause storms to slow down just over the protected beach and preferentially destroy any ships moored there.

4. So much erosion could eventually occur downcurrent from the breakwater that the protected beach would be exposed.

Explanation / Answer

Part D- 2. The sand could build up behind the breakwater so much that the beach connects with the breakwater.

Part E -1. Damming the river would decrease the amount of sediment reaching the beach and cause the beach to shrink.

Part F- 3. At a point bar

Part G - 3. More erosion could occur, because the stream is carrying less sediment for its velocity than it should.

Part H - 4. approximately 2 inches/year

Explanation

Total eroded =5 feet (60 inches)

1983-1954 =29

Erosion rate = 60/29 = 2.06inches/year

Part I - Information in the question is insufficient -To answer this question, length of Brown's Island is required, it is not given.

Part J- 1. between 6 and 7 feet/year

Explanation

Total Erosion is around 120 feet in 2003

2003 - 1988 = 15 years

Erosion rate =120 feet /15 years = 8 feet/yr.

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