SUBURBAN STREETS 191 



can be kept relatively high and dry. Roadways 

 are generally made crowning in the center, so that 

 water runs to the sides, but frequently the fall 

 lengthwise of the roadway is less than it should 

 be. City engineers are usually inclined to make 

 the grade along the length of a street as nearly 

 level as possible. Authorities who have given the 

 subject of roads considerable study recommend a 

 fall lengthwise of not less than one foot in one 

 hundred and twenty -five, nor more than six feet 

 in one hundred. Such grades are not always fea- 

 sible, but a certain amount of variation in level 

 can usually be made in a residence street which 

 will make it much more pleasing in appearance, 

 and have certain practical advantages in keeping 

 the street dry. The water is usually confined tcr 

 the edge of the pavement by curbing, which may 

 rise anywhere from four to fourteen inches 

 above the surface. This causes all the water fall- 

 ing on the roadway to seek the catch -basin and 

 be wasted, excepting for its use in flushing the 

 sewer. If the curbing, which is really unneces- 

 sary in most cases, were omitted, much of the 

 surface water would soak into the ground between 

 the sidewalk and the pavement, doing much good 

 to trees, shrubs and grass. The roots of the trees 

 naturally extend as far, or farther, than their 

 branches, and for their good the ground under 

 the pavement and sidewalk should be supplied 

 with a certain amount of moisture. 



