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<br />NPIC RESERVOIR #4 REHABILITATION
<br />
<br />An earth dam with a maximum height of 23 feet and a total crest length of approximately 1400 feet
<br />impounds NPIC Reservoir # 4. At the decreed storage level of gage height 22 feet, the reservoir has a
<br />storage capacity of 1669 acre-feet, Currently the reservoir is under restriction to gage height 17 feet.
<br />As reported in the most current State Engineers Inspection Report, the downstream outlet structure is
<br />deteriorated both the upstream and downstream slopes of the dam are over steep, and there is seepage
<br />along the toe of the dam, The existing spillway. located at the left abutment, would spill along the toe
<br />of the dam in an overflow situation and cause erosion of th5 unprotected downstream slope and toe of
<br />the dam. Additional riprap is also needed on the left abutment,
<br />
<br />One of two options for the rehabilitation of the reservoir considered raising the crest of the dam
<br />approximately four feet to a gage height of 26 feet, move the spillway to the center of the dam, replace
<br />the existing outlet works and Parshall flume. install a new toe drain and riprap areas as required, This
<br />would enable NPIC to store water to the decreed level of 22 feet and provide four feet of freeboard,
<br />Raising the crest to this elevation would require an extension of the dam to the west for approximately
<br />1500 feet and to the north and west another 500 feet. The westward extension could be constructed on
<br />land owned by NPIC but the eastward extension would infringe upon neighboring property, The
<br />resulting high water line would be near, or onto private property, A cost estimate for this option is
<br />shown in Table 5.
<br />
<br />TABLE 5. COST ESTIMATE FOR NPIC #4 DAM REHABILITATION OPTION #1.
<br />
<br />ITEM DESCRIPTION QUANTITY UNITS UNIT PRICE AMOUNT
<br />I. MOBILIZATION, INSURANCE, BONDS 1.00 L.S, $24,000,00 $24,000.00
<br />2, STRIPPING AND REMOVING TREES 1.00 L.S. $10,000.00 $10,000.00
<br />3, DEWATERING 1.00 L.S. $10,000,00 $10,000,00
<br />4, GENERAL EARTH MOVING
<br /> a) Dam Borrow and Fill 28000,00 C,Y, $4,00 $112,000.00
<br /> b) Inlet Channel Excavation 3680.00 C.Y, $3,00 $11,040,00
<br /> c) Breach Excavation and Fill 3600,00 C.Y, $4,00 $14,400,00
<br />5. RIPRAP 6800.00 TON $25.00 $170,000.00
<br />6, RIPRAP BEDDING 2100.00 TON $18.00 $37.800,00
<br />7, TOE DRAIN 1200,00 L.F, $15,00 $18.000,00
<br />8. REPLACE OUTLET WORKS
<br /> a) Demolition and Removal 1.00 L.S, $4,000.00 $4.000.00
<br /> b) Inlet Structure With Gate 1.00 L.S, $20,000.00 $20,000.00
<br /> c) Outlet Tower With Gate 1.00 L.S. $36,600.00 $36.600.00
<br /> d) Outlet Headwall 1.00 L.S, $12,000.00 $12,000.00
<br /> e) 30" Concrete Pipe 150.00 L.F. $110,00 $16,500,00
<br />9, SPILLWAY 50,00 L.F. $150,00 $7,500,00
<br />10. PARSHALL FLUME 1.00 L.S, $15.000,00 $15,000.00
<br />11, SEEDING 1 L.S, $15,000,00 $15,000,00
<br />12. ENGINEERING AND CONTINGENCIES 1 L.S, $160,152,00 $160,152,00
<br />
<br />TOTAL $693,992.00
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<br />Page 12
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