Lab 10; E-OC103 \"Exploring the Deep\" Coastal Erosion You have just won the lot
ID: 295816 • Letter: L
Question
Lab 10; E-OC103 "Exploring the Deep" Coastal Erosion You have just won the lottery (or perhaps were chosen in the 1st round of the NBA draft), and are going to use some of your windfall to build yourself a dream house on the Oregon Coast. The property you have chosen sits on top of a cliff with a spectacular view of the ocean. You would like to build your mansion as close to the cliff edge as possible, but erosion of the sea cliff is such that the cliff edge is retreating from the sea at an average rate of 25 cm/yr. In accordance with your building permit, the outermost wall of your house must be at least 20 feet (6.1 m) from the cliff edge, and since you want the best possible view, you build it exactly at the 20-foot mak. 1. What is the average retreat rate of the cliff in inches/year? 2. At the average retreat rate, how long until the cliff face retreats to the wall of your house (at which time you will probably want to move out)? (2 pts.) (2 pts.) 3. Assume that you can find special "erosion insurance" that costs $1800/yr for a house within 8 m of a sea cliff, but costs $4800/yr for a house within 2 m of a sea cliff. How long until erosion reduces your original 6.1 m setback to only 2 m and your insurance rate goes up? ts 4. A consulting engineer you hired tells you that you can delay by 10 years the retreat of the sea cliff to the 2 m mark from your house if you install riprap and other erosion control features at the base of the cliff. How much in extra insurance payments would you save during that 10-year delay? 5. Installing the erosion control features in the previous question will cost $20,000, but will cause increased erosion to your next-door neighbor's property, and it will cost you $8000 in legal fees to defend yourself from your neighbor's lawsuit. Is the insurance savings more than the cost of the erosion control features and the legal fees combined? (2 pts.) 6. In your opinion, is the total cost of the erosion control, including installation, legal fees, and bad blood with your neighbor, worth it because of the additional time it will give you before you have to abandon your house? Conversely, what would you do if the tables were turned, and your neighbor installed an erosion control system that caused increased erosion to your property? (2 pts.) To answer the following 3 questions, read the article published in 2000 in the FEMA News (Federal Emergency Management Agency) on coastal erosion (available as a PDF under the Lab 10 heading in Week 10 Course Documents) 7. Approximately what proportion of structures within 500 feet of the U.S. coastlines and Great Lake:s shorelines will fall victim to erosion by the year 2060? 8. What is the average annual cost of coastal erosion to U.S. homeowners?__(3 pts.) 9. True or false: The National Flood Insurance Program (NFIP) covers erosion damage that occurs during floods, but does not cover damage from gradual erosion. tsExplanation / Answer
1. 25 cm = 9.84 inches as per the conversion factor: 1 cm = 0.3937 inch
Thus, the average retreat rate of the cliff in inches per year = 9.84 inches/year
2. Given that the outermost wall is at a 20-foot or 240-inch mark, the cliff will retreat to the wall in
240 / 9.84 = 24.3 years.
3. It is already calculated in Q.1) that the cliff is retreating at a rate of 0.24 m per year. Erosion will shift the cliff by 4.1 meters (6.1 m- 2 m) and bring the house within 2 m of the cliff in
4.1 / 0.24 = 17 years.
After 17 years, the insurance cost would go up from $1800 to $4800 per year.
4. There would be an extra cost of $3000 per year ($4800 - $1800) towards insurance if the erosion is not delayed by 10 years using riprap installation. A 10-year delay would mean a saving of 3000 x 10 = $30,000
5. Cost of erosional features and legal fees = $20,000 + $8,000 = $28,000 which is less than the $30,000
So, the answer is yes, the insurance savings is more than the cost of erosional features and legal fees combined.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.