16-24) The Highridge Water District needs an additional supply of water from Steep Creek. The engineer has selected two plans for comparison: Gravity plan: Divert water at a point 10 miles up Steep Creek and carry it through a pipeline by gravity. Pumping plan: Divert water at a point near the district and pump it through 2 miles of pipeline. The pumping plant can be built in two stages: half now and half 10 years later. Gravity Pumping Initial investment Investment in 10th year Operation, maintenance, $2,800,000 $1,400,000 0 200,000 25,000 10,000 replacements, per year Average annual power cost First 10 years Next 25 years 50,000 100,000 0 Use a 35-year analysis period and 5% interest. Salvage values can be ignored. Use the conventional benefit-cost ratio method to select the more economical plan. 16-24) The Highridge Water District needs an additional supply of water from Steep Creek. The engineer has selected two plans for comparison: Gravity plan: Divert water at a point 10 miles up Steep Creek and carry it through a pipeline by gravity. Pumping plan: Divert water at a point near the district and pump it through 2 miles of pipeline. The pumping plant can be built in two stages: half now and half 10 years later. Gravity Pumping Initial investment Investment in 10th year Operation, maintenance, $2,800,000 $1,400,000 0 200,000 25,000 10,000 replacements, per year Average annual power cost First 10 years Next 25 years 50,000 100,000 0 Use a 35-year analysis period and 5% interest. Salvage values can be ignored. Use the conventional benefit-cost ratio method to select the more economical plan