Alternative plans are being considered for an irrigation canal between a natural freshwater reservoir and an agricultural region in Balochistan. One of the plans is for the canal to pass through mountains via tunnels and also to cross a series of ravines and will necessitate the construction of structures to carry the water over those land features. This alternative will involve lining the canal. The other plan involves an unlined but longer canal that will not involve any tunneling or bridges. On the basis of the cost and performance attributes itemized in Table, determine which plan is more economically feasible. Use a 5% discount rate.
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Table 20.4 Data for Exercise 13
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Plan A
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Plan B
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Distance
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3.5
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12
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Total excavation needed (mils,ft𝟑)
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0.5
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0.1
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Bridge construction cost ($M)
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1
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0
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Tunnel construction cost ($M)
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0.8
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0
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Annual maintenance of bridge and tunnels ($M)
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0.2
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0
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Lining cost ($M)
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2
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0
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Annual cost of channel maintenance
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0.15
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1
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Annual loss of water due to percolation (mils, ft𝟑)
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0.05
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1.5
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Service life (yr)
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20
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5
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