Second: To find the cost of 15–inch pipe at a depth of 9.0 feet, enter the diagram at a diameter of 15 inches and continue down until the intersection with a depth of trench at 9 feet is found. Now go diagonally parallel to lines running from left to right upwards to the intersection with the diagonal line running from left to right downwards corresponding to the factor of 11 found above. The vertical line passing through this point shows the cost to be 67 cents per foot.
COST OF SEWER CONSTRUCTION AT ATLANTIC, IOWA
Material: Clay, not difficult to spade and requiring little or no bracing and practically no pumping. All hand work except backfill which was done by team and scraper. Depth of trench averaged 8.2 feet; width 30 inches. Diameter of pipe 10 inches.
───────────────────────────────────────────────────────────┬─────┬───── Item │Wage,│Cost, │Cents│Cents │ per │ per │Hour │Foot. ───────────────────────────────────────────────────────────┼─────┼───── Pipe. │ │0.20 Hauling team and driver. │ 30│ .003 Hauling. Man helping. │ 17│ .001 Cement and sand. │ │ .006 Pipe layers. │ 22│ .014 Pipe layer’s helper. │ 17│ .014 Trenching. Top men. │ 17│ .027 Trenching. Bottom men. │ 17│ .130 Trenching. Scaffold men. │ 17│ .002 Trenching. Bracing men. │ 17│ .002 Backfilling. Shovel. │ 17│ .010 Backfilling. Team and scraper. │ 30│ .008 Backfilling. Man and scraper. │ 17│ .005 Water boy. │ 10│ .006 Foreman. │ 30│ .022 ───────────────────────────────────────────────────────────┼─────┼───── Total. │ │ .450 ───────────────────────────────────────────────────────────┴─────┴─────
The construction of sewerage works may be paid for by the issue of municipal bonds, by special assessment, by funds available from the general taxes, or by private enterprise.
=10. Bond Issues.=—A municipal bond is a promise by the municipality to pay the face value of the bond to the holder at a certain specified time, with interest at a stipulated rate during the interim. The security on the bond is the taxable property in the municipality. The legal restrictions thrown around municipal bond issues, the value of the taxable property in the municipality, all of which may be used as security for municipal bonds, and the fact that a municipality can be sued in case of default, make municipal bonds desirable and provide a good market for their sale. The funds available from a municipal bond issue are limited by the amount that the legal limit is in excess of the outstanding issues. The legal limit varies in different states from about 5 to 15 per cent of the assessed value of the property in the municipality. In some cases the amount available from municipal bonds has been increased by forming a municipality within a municipality such as a sanitary district, a park district, a drainage district, etc., which comprises a large portion or all of an existing municipal corporation. This case is well illustrated in some parts of the City of Chicago where the municipal taxing powers are shared by the City government, the Sanitary District, and Park Commissioners. The right to create a new municipal corporation must be granted by the state legislature. Knowledge of fixed bonds, serial bonds, life of bonds, sinking funds, etc. is an important part of an engineer’s education.[14]