STREET GRADES. The fixing of street grades is one of the most important functions of municipal engineering, since the grade system of the streets is the foundation of all municipal engi neering matters. The grades should be established before the sewer system is planned; and if they are established before the property is improved. the problem is comparatively simple, since they may be laid chiefly with reference to obtaining desirable gradients for the street within proper limits of cost. But when buildings have been erected, sidewalks constructed, and trees planted, it is frequently extremely difficult to secure grades which will harmonize the various and conflicting interests.
Drainage.The streets are the natural drainage channels of the city; the lots must drain into them, and the house must drain into the sewers placed in the streets. When no storm water sewers are to be constructed, the grades become very im portant, since the streets must provide for the surface drainage of the city, and particular consideration must be given to relative grades and gutter capacities in order to prevent the excessive concentration of storm water at the lower levels and to provide for its proper distribution and disposal.
light, and only a little, as to the proper method of answering this question. Apparently engineers are inclined to overestimate the disadvantage to traffic of a slight grade. Practical experience has demonstrated that there is not much difference in effect upon the cost of transportation between level roads and those having grades of 2 or 3 per cent unless such grades are very long or have an unusually smooth and well-kept surface, Effect upon Abutting Property.The private interests of the property holder should be carefully considered; although it is frequently impossible to establish proper grades without injury to the adjoining property. The general question is how far private interests should be sacrificed to the general good. It is better that the city or the other residents on the street should pay the owner damages than that lasting detriment should be done to the appear ance of the street or to the traffic.
General Appearance. Some attention should be paid to the appearance of a longitudinal view of the pavement. It is de sirable that the longitudinal grade be not changed so frequently as to give the street a wavy appearance. Further, the transverse grades at street intersections and on side hills should be so arranged as not to produce a confused appearance in looking along the street. The grades of the streets, both longitudinal and transverse, have a material effect upon the general appearance and beauty of the city.