Engineer s Report Drainage District #93 Main Tile Improvements Wright County, Iowa MEC Figure 1: Wright County Drainage District #93

Transcription

1 April 30, 2015 Board of Supervisors Wright County Courthouse 115 North Main Street Clarion, IA RE: Engineer s Report Drainage District #93 Main Tile Improvements Wright County, Iowa MEC Dear Board Members: INTRODUCTION Wright County hired McClure Engineering (MEC) to investigate potential improvements to the main drain tile of Drainage District 93. This report was initiated by a landowner s request to improve drainage and details the potential options for remediation of the tile. The project area is shown in Figure 1. The Drainage District boundary is shown in red, the main tile location in blue. Figure 1: Wright County Drainage District #93

2 BACKGROUND District #93 Main Drain begins in the NE ¼ of the SW ¼ of Section 12, Lincoln Township. The tile outlets into the main open ditch of District #5 on the east side of Sycamore Avenue in the SE ¼ of the NW ¼ of Section 19, Blaine Township. MEC gathered tile infrastructure data using existing drawings and Iowa Department of Natural Resources (DNR) GIS data which can be found at There is approximately 12,300 feet (2.31 miles) of tile in DD93, which drains into a surface ditch in Section 19. DD93 includes 1, acres of farmland, with the main tile serving approximately 1, of those acres. A reclassification of the tile was performed in April of Original tile profile data was based on profiles provided by Wright County. The existing capacity calculations were based on the documented pipe size and drainage areas calculated from Iowa Department of Natural Resources GIS data. Table 1 summarizes the existing capacity. The main tile in DD93 operates at a 1/4 to 2/3 inch drainage coefficient. The Iowa Drainage Guide recommends a tile drainage coefficient of 1/2. TABLE 1 EXISTING MAIN DRAIN 12,296-11, % /2 11,100-7,100 16" 0.72% /3 7,100-4,700 22" 0.21% /4 4,700-3,900 30" 0.19% 1, /4 3, " 0.08% 1, /4 Figure 2 illustrates the existing ground profile, design tile flowline, and top-ofpipe for the design tile in Option 3, which is the worst case scenario in terms of available cover. Figure 3 illustrates the proposed lateral 1 existing ground profile, design tile flowline, and top-of-pipe for the design tile in Option 6, which is the worst case scenario in terms of available cover.

3 Figure Existing Ground Elevation Top of New Tile Elevation New Tile Flowline Elevation

4 Figure Existing Ground Elevation Top of Tile Elevation New Tile Flowline Elevation IMPROVEMENT OPTIONS The following improvement options were analyzed: Option 1. Replace Existing Tile Starting at 22 Tile 1/2 Drainage Coefficient This option replaces 7,100 feet of tile beginning with the 22 tile in Section 13, south of the existing railroad, and ending at the open ditch in Section 19. The existing tile in Section 12 and 13, north of the railroad provides a 1/2 drainage coefficient, but the remaining tile south of the railroad does not. This restricts the flow of the upstream tile north of the railroad. By increasing the downstream tile size, capacity of the system and improved drainage will be achieved, providing a

5 1/2 drainage coefficient for the entire main. A cost estimate for Option 1 can be found in Table 2. TABLE 2: OPTION 1 SUMMARY 7,100-4,700 30" 0.21% /2 4,700-3, % 1, /2 3, % 1, /2 Total Estimated Cost = $480, Average Cost per acre = $ Option 2. Replace Existing Tile ¾ Drainage Coefficient Option 2 proposes to replace the existing tile both north and south of the railroad, to provide a 3/4" drainage coefficient. A breakdown of the replacement tile can be found in the Table 3. The cost estimate associated with this option is included with this report. TABLE 3 OPTION 2 DESIGN SUMMARY 12,376-11, % /4" 11,100-9,200 18" 0.72% /4" 9,200-7, % /4" 7,100-4,700 42" 0.19% 1, /4" 4,700-3,900 42" 0.19% 1, /4" 3, " 0.08% 1, /4" Total Estimated Cost = $910, Average Cost per acre = $ Option 3. Replace Existing Tile 1 Drainage Coefficient Option 3 proposes to replace the existing tile, similar to Option 2, to provide a 1" drainage coefficient. A breakdown of the replacement tile can be found in the Table 4. The cost estimate associated with this option is included with this report.

6 TABLE 4 OPTION 3 DESIGN SUMMARY 12,376-11, % " 11,100-9,200 18" 0.72% " 9,200-7, % " 7,100-4,700 42" 0.19% 1, " 4,700-3,900 42" 0.19% 1, " 3, " 0.08% 1, " Total Estimated Cost = $934, Average Cost per acre = $ Option 4. Tile Replacement-North Side of Railroad 1/2 Drainage Coefficient This option replaces 7,400 feet of tile beginning at the open ditch in Section 19, and terminating approximately 100 feet north of the railroad in Section 13, providing a 1/2 drainage coefficient for the entire main. A summary and cost estimate for Option 4 can be found in Table 5. TABLE 5: OPTION 4 SUMMARY 7,400-4,700 30" 0.21% /2 4,700-3, % 1, /2 3, % 1, /2 Total Estimated Cost = $495, Average Cost per acre = $ Option 5. Tile Replacement-North Side of Railroad 3/4 Drainage Coefficient This option is identical to Option 4, but provides a 3/4 drainage coefficient. A summary and cost estimate for Option 5 can be found in Table 6. TABLE 6 OPTION 5 DESIGN SUMMARY 7,400-4,700 42" 0.19% 1, /4" 4,700-3,900 42" 0.19% 1, /4" 3, " 0.08% 1, /4" Total Estimated Cost = $689, Average Cost per acre = $509.21

7 Option 6. Tile Replacement-North Side of Railroad 1 Drainage Coefficient This option is identical to Option 4, but provides a 1 drainage coefficient. A summary and cost estimate for Option 6 can be found in Table 7. TABLE 7 OPTION 6 DESIGN SUMMARY 7,400-4,700 42" 0.19% 1, " 4,700-3,900 42" 0.19% 1, " 3, " 0.08% 1, " Total Estimated Cost = $689, Average Cost per acre = $ Option 7 Tile Replacement-North Side of C48 1/2 Drainage Coefficient This option replaces 8,600 feet of tile beginning at the open ditch in Section 19, and terminating approximately 100 feet north of the County Road C-48 in Section 12, providing a 1/2 drainage coefficient for the entire main. A summary and cost estimate for Option 7 can be found in Table 8. TABLE 8: OPTION 7 SUMMARY ,400 18" 0.72% /2 7,400-4,700 30" 0.21% /2 4,700-3, % 1, /2 3, % 1, /2 Total Estimated Cost = $497, Average Cost per acre = $ Option 8. Tile Replacement-North Side of C48 3/4 Drainage Coefficient This option is identical to Option 7, but provides a 3/4 drainage coefficient. A summary and cost estimate for Option 5 can be found in Table 9.

8 TABLE 9 OPTION 8 DESIGN SUMMARY 8,900-7, % /4" 7,400-4,700 42" 0.19% 1, /4" 4,700-3,900 42" 0.19% 1, /4" 3, " 0.08% 1, /4" Total Estimated Cost = $691, Average Cost per acre = $ Option 9. Tile Replacement-North Side of C48 1 Drainage Coefficient This option is identical to Option 7, but provides a 1 drainage coefficient. A summary and cost estimate for Option 9 can be found in Table 10. TABLE 10 OPTION 9 DESIGN SUMMARY , % " 7,100-4,700 42" 0.19% 1, " 4,700-3,900 42" 0.19% 1, " 3, " 0.08% 1, " Total Estimated Cost = $797, Average Cost per acre = $ WETLANDS Improvement projects have the potential to affect wetlands and farmed-wetlands. It is up to the individual landowner to notify the Board of Supervisors if the project will disturb any wetlands that could result in the need for mitigation to avoid jeopardizing any producers FSA program eligibility. Landowners need to present this information at or before the public hearing, or no later than prior to approval of an improvement project. ADMINISTRATION Because the cost of repairs exceeds $50,000 a public hearing will be necessary and notice given as provided in Section para 1.c. If the project is approved, a public bid letting will be required. After reviewing this report a public hearing date should be set.

9

10 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 1 - DD93 Main Tile Replacement,1/2 Drainage Coefficient item description quantity unit unit cost extenstion 1 30" RCP 2400 lf $38.16 $91, " RCP 800 lf $42.24 $33, " RCP 3900 lf $57.25 $223, Field Tile Connections 35 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock 355 tn $23.25 $8, Crush and Bury Existing Tile 7100 lf $1.00 $7, DD 93 Subtotal $374, Total Construction $374, % Contingency $37, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $36, Estimated Total Project $480, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing Sycamore Ave (Secondary Roads Expense): $6, Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, /1/2015

11 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 2- DD93 Main Drain Replacement, 3/4" Drainage Coefficient item description quantity unit unit cost extenstion 1 18" RCP 3176 lf $25.44 $80, " RCP 2100 lf $46.74 $98, " RCP 3200 lf $57.25 $183, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 61 ea $ $12, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $14, Crush and Bury Existing Tile lf $1.00 $12, DD 93 Subtotal $741, Total Construction $741, % Contingency $74, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $63, Estimated Total Project $910, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing Sycamore Ave (Secondary Roads Expense): $6, Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Trenched Road Crossing County Road 48 (Secondary Roads Expense): $6, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

12 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 3- DD93 Main Drain Replacement, 1" Drainage Coefficient item description quantity unit unit cost extenstion 1 18" RCP 3176 lf $25.44 $80, " RCP 5300 lf $57.25 $303, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 61 ea $ $12, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $14, Crush and Bury Existing Tile lf $1.00 $12, DD 93 Subtotal $763, Total Construction $763, % Contingency $76, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $63, Estimated Total Project $934, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing Sycamore Ave (Secondary Roads Expense): $6, Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Trenched Road Crossing County Road 48 (Secondary Roads Expense): $6, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

13 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 4 - Tile Replacement-North Side of Railroad 1/2 Drainage Coefficient item description quantity unit unit cost extenstion 1 30" RCP 2700 lf $38.16 $103, " RCP 800 lf $42.24 $33, " RCP 3900 lf $57.25 $223, Field Tile Connections 37 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock 370 tn $23.25 $8, Crush and Bury Existing Tile 7400 lf $1.00 $7, DD 93 Subtotal $387, Total Construction $387, % Contingency $38, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $38, Estimated Total Project $495, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

14 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 5 - Tile Replacement-North Side of Railroad 3/4 Drainage Coefficient item description quantity unit unit cost extenstion 1 42" RCP 3500 lf $57.25 $200, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 37 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $8, Crush and Bury Existing Tile 7400 lf $1.00 $7, DD 93 Subtotal $563, Total Construction $563, % Contingency $56, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $38, Estimated Total Project $689, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

15 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 6 - Tile Replacement-North Side of Railroad 1 Drainage Coefficient item description quantity unit unit cost extenstion 1 42" RCP 3500 lf $57.25 $200, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 37 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $8, Crush and Bury Existing Tile 7400 lf $1.00 $7, DD 93 Subtotal $563, Total Construction $563, % Contingency $56, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $38, Estimated Total Project $689, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

16 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 7 - Tile Replacement-North Side of C-48 1/2 Drainage Coefficient item description quantity unit unit cost extenstion 1 18" RCP 1500 lf $25.44 $38, " RCP 2700 lf $38.16 $103, " RCP 800 lf $42.24 $33, " RCP 3900 lf $57.25 $223, Field Tile Connections 37 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock 370 tn $23.25 $8, Crush and Bury Existing Tile 8900 lf $1.00 $8, DD 93 Subtotal $388, Total Construction $388, % Contingency $38, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $38, Estimated Total Project $497, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below C-48 (County Road Expense): $10, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

17 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 8 - Tile Replacement-North Side of C-48 3/4 Drainage Coefficient item description quantity unit unit cost extenstion 1 36" RCP 1500 lf $46.74 $70, " RCP 3500 lf $57.25 $200, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 37 ea $ $7, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $8, Crush and Bury Existing Tile 8900 lf $1.00 $8, DD 93 Subtotal $565, Total Construction $565, % Contingency $56, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $38, Estimated Total Project $691, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below C-48 (County Road Expense): $10, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015

18 Engineer's Estimate of Probable Cost DD93 Main Tile Replacement Options Option 6 - Tile Replacement-North Side of Railroad 1 Drainage Coefficient item description quantity unit unit cost extenstion 1 42" RCP 5000 lf $57.25 $286, " RCP 3900 lf $85.89 $334, " CMP Tile Outlet 20 lf $70.00 $1, Field Tile Connections 44 ea $ $8, Locate Existing Tile 16 hr $ $3, Trench Stabilization Rock tn $23.25 $10, Crush and Bury Existing Tile 8900 lf $1.00 $8, DD 93 Subtotal $654, Total Construction $654, % Contingency $65, Survey, Records Review, Report, & Hearings $10, Survey, Plans, Specifications, Bidding Phase & Contract Documents $10, Construction Staking, Construction Review & Administration $10, Legal Notices, Miscellaneous $1, ROW Damages ($2,250/ac) $45, Estimated Total Project $797, Average Assessment DD93: $ETP/ acres = $ Trenched Road Crossing 245th Street (Secondary Roads Expense): $6, Bored Crossing Below C-48 (County Road Expense): $10, Bored Crossing Below Railroad (Railroad Expense): $25, /1/2015