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City of Plymouth
WW.105 SEWER DESIGN
- DESCRIPTION
- All sanitary and storm sewers shall be placed according to the City of Plymouth Design Standards and Specifications, INDOT Specifications, and the requirements of ISDH and IDEM.
- DELIVERY AND HANDLING
- All materials must be new and not used, no main line gravity sewer conveying raw sewage shall be less than eight (8) inches (20 cm) in diameter.
- In general, sewers shall be sufficiently deep to prevent freezing. Oversizing of sewers will not be allowed to justify using flatter slopes.
- All sanitary sewers shall be designed and constructed to give mean velocities, when flowing full, of greater than two (2) feet per second (0.61 m/s), based on Kutter's formula using an "n" value of 0.013. The following are the minimum slopes which should be provided as required by the City of Plymouth; however, slopes greater than these are desirable:
|
Sanitary Sewer
Size (in.) |
City Req'd.
(ft/100ft) |
Max. Slope
(ft/100ft) |
| 4 |
1.20 |
10.8 |
| 6 |
0.63 |
6.5 |
| 8 |
0.45 |
4.5 |
| 10 |
0.33 |
3.4 |
| 12 |
0.27 |
2.7 |
| 15 |
0.20 |
2.0 |
| 18 |
0.17 |
1.6 |
| 21 |
0.15 |
1.3 |
| 24 |
0.13 |
1.1 |
| 30 |
0.11 |
0.8 |
| 36 |
0.10 |
0.6 |
- All storm sewers shall be designed and constructed to give mean velocities, when flowing full, of greater than two and one-half (2.5) feet per second (0.30 m/s), based on Kutter's formula using an "n" value of 0.013. The following are the minimum slopes which should be provided as required by the City of Plymouth; however, slopes greater than these are desirable:
|
Storm Sewer
Size (in.) |
City Req'd.
(ft/100ft) |
Max. Slope
(ft/100ft) |
| 4 |
2.6 |
10.8 |
| 6 |
1.45 |
6.5 |
| 8 |
0.90 |
4.5 |
| 10 |
0.65 |
3.4 |
| 12 |
0.53 |
2.7 |
| 15 |
0.39 |
2.0 |
| 18 |
0.30 |
1.6 |
| 24 |
0.22 |
1.1 |
| 30 |
0.18 |
0.8 |
| 36 |
0.15 |
0.6 |
For storm sewers, where velocities greater than ten (10) feet per second (3m/s) are attained, special provision shall be made to protect against displacement by erosion and shock, as applicable.
Sewers on 20% slope or greater shall be anchored securely with concrete anchors spaced as follows:
- Not over 36 feet (11 m) center to center on grades 20% and up to 35%
- Not over 24 feet (7.3 m) center to center on grades 35% and up to 50%
- Not over 16 feet (4.9 m) center to center on grades 50% and over.
- Sewers shall be laid at least ten (10) feet (3.0 m) horizontally from any existing or proposed water main. The distances shall be measured edge to edge.
- Sewers crossing water mains shall be laid to provide a minimum vertical distance of eighteen (18) inches (46cm) between the outside of the water main and the outside of the sewer. This shall be the case where the water main is either above or below the sewer. The crossing shall be arranged so that the joints will be equidistant and as far as possible from the water main. Where a water main crosses under a sewer, adequate structural support shall be provided for the sewer to prevent damage to the water main. Where water and sewer lines cross and it is impossible to obtain proper horizontal and vertical separation as stipulated above, the sewer shall be designed and installed equal to the water line, and shall be pressure tested to assure watertightness prior to backfilling.
- Laterals
- Minimum size for sanitary sewer laterals shall be four (4) inches in diameter.
- There shall be a minimum of one clean-out required for each sanitary sewer lateral with additional clean-outs every 100'.
- Approved grease traps are required at all establishments, except residential, that have food service.
- Approved sediment traps shall be used when required by the Sewer Superintendent.
- Connection of downspouts, sump pumps, and yard drains is strictly prohibited by local, state, and federal regulations and violations will be subject to penalties.
- The Contractor shall keep one (1) copy of all project specifications, plans, addenda, modifications, supplemental drawings, shop drawings, and change orders at the project site in good order and annotated to show all changes made during the construction process. In addition, the Contractor shall keep one set of "As-Built" Drawings for the Project. These "As-Built" Drawings shall show all final elevations, all final dimensions and tie downs for buried pipes, valves, fittings, structures, etc., all final dimensions and sizes for pipes and structures, and all other information as necessary to constitute "as-built" records. These documents shall be kept daily by the Contractor and routinely checked by the City Representative for completeness and accuracy based on the City Representative's daily records and notes. Upon completion of the project or beneficial occupancy, whichever comes first, these record "As-Built" Drawings together with any other annotated supplemental plans, drawing, sketches, etc. shall be delivered to the City Representative in the form of 3 (three) sets of plans and on disk in the City's current version of Auto-Cad, for his final review and approval. If approved, the documents will be delivered to the Owner within thirty (30) days of completion of the job. If disapproved, they will be returned to the Contractor for corrections, as necessary.
- The Contractor shall furnish three (3) sets of equipment manufacturer's operation and maintenance manuals for each item of mechanical and electrical equipment furnished.
- The Contractor shall provide the services of the manufacturer's representative(s) to supervise the start-up and instruct City personnel in the operation and maintenance of the equipment. The Contractor shall make adjustment of all automatic controls and safety devices, balance and adjust all air and water flow, make proper setting of all valves, and perform all other necessary operations to make the equipment, systems, and facilities fully operable and where required, be oiled and greased with all grease cups, oilers, etc., left filled.
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PLYMOUTH CODE
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2003 ELECTION RESULTS
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