5. A flood control district is considering increasing the size of a channel to reduce flood damage to the surrounding area. The channel can currently contain the 10 year flood. The cost of enlarging the channel, the annual maintenance cost, the return period, T, and probability of occurrence, P, is given below. Assume that a flood causes S3,000,000 damage, and the districts MARR is 7%. Determine the economically best size of the channel. Use a life of 50 years, and solve by the annual worth method, and also by the benefit-cost ratio Alternative Cost Annual Maintenance Years $30,000 36,000 45,000 48,000 No Improvement 10 20 50 100 0.10 0.05 $1,000,000 0.02 1,600,000 0.02,500,000 5. A flood control district is considering increasing the size of a channel to reduce flood damage to the surrounding area. The channel can currently contain the 10 year flood. The cost of enlarging the channel, the annual maintenance cost, the return period, T, and probability of occurrence, P, is given below. Assume that a flood causes S3,000,000 damage, and the districts MARR is 7%. Determine the economically best size of the channel. Use a life of 50 years, and solve by the annual worth method, and also by the benefit-cost ratio Alternative Cost Annual Maintenance Years $30,000 36,000 45,000 48,000 No Improvement 10 20 50 100 0.10 0.05 $1,000,000 0.02 1,600,000 0.02,500,000