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Table 2.- Construction cost opinion
<br />Item
<br />Quantity
<br />unit
<br />Unit cost
<br />(dollars)
<br />Estimated cost
<br />(dollars)
<br />In- channel recharge facilities
<br />Inflatable dam
<br />200 LF'
<br />2,850
<br />570,000
<br />Fuse plugs
<br />450 LF
<br />78
<br />35,000
<br />Concrete piers
<br />2 each
<br />20,000
<br />40,000
<br />Spur basin excavation
<br />10,500 CY2
<br />2
<br />32,000
<br />Demonstration bank protection
<br />800 LF
<br />75
<br />60,000
<br />In- channel subtotal
<br />737,000
<br />Off - channel recharge facilities
<br />Alamo Wash diversion structure
<br />1 LS3
<br />30,000
<br />30,000
<br />Diversion pipeline
<br />1.025 LF
<br />144
<br />150,000
<br />Outlet structure
<br />LS
<br />20,000
<br />20,000
<br />West County basin
<br />47,500 CY
<br />2
<br />95,000
<br />Off - channel subtotal
<br />295,000
<br />Recreation facilities
<br />Alamo Wash bridge
<br />1 each
<br />40,000
<br />40,000
<br />Restroom /wetland
<br />1 LS
<br />20,000
<br />20,000
<br />Interpretive centers
<br />3 each
<br />1,000
<br />3,000
<br />Pavilion
<br />1 each
<br />30,000
<br />30,000
<br />Parking
<br />1 each
<br />100,000
<br />100,000
<br />River Park (south bank)4
<br />1 LS
<br />700,000
<br />700,000
<br />River Park (north bank)
<br />1 mile
<br />200,000
<br />200,000
<br />Recreation facilities subtotal
<br />1,093,000
<br />Project subtotal
<br />2,125,000
<br />Contingency (15 percent)
<br />320,000
<br />Engineering (15 percent)
<br />370,000
<br />Total
<br />2,815,000
<br />' Linear feet.
<br />2 Cubic yards.
<br />3 Lump sum.
<br />a Includes vegetation enhancement.
<br />increased the cost of the structure by roughly $400,000. The special foundational
<br />requirements of rubber dams or other in- channel diversion structures must be taken
<br />into consideration, as these can exceed the cost of the diversion structure itself.
<br />Economic Feasibility
<br />The Rillito Recharge Project would recharge an average of 3,500 acre -feet of stormwater
<br />per year. The construction cost for the recharge facilities was estimated to be
<br />$1,364,820, including contingency and engineering (CHZMHill, 1992, table 2). If the
<br />project were financed over a 20 -year period at 7.0 percent interest, annual capitalized
<br />costs would be $130,000 for the recharge facilities. Thus, the cost to recharge 3,500 acre -
<br />feet per year would be roughly $37 per acre -foot, excluding operation and maintenance.
<br />Program Summary Report Part 111 - Demonstration Project Summary Reports 15
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