Show ROAD I BUILDING DRAINAGE FOR GOOD ROADS Essential Feature of an Improved Highway Highway Another y Another R Requisite Is Firm Foundation Prepared by the United States Department Depart Depart- ment of A An essential rt feature re of f ni Improved road Is adequate drainage Thorough drainage IB JI so Sf necessary that It la is practically impo Ible to maintain a satisfactory sat sat- road unless It b be given proper prop prop- er attention Another prime requirement requirement requirement require require- ment wherever a hard surface road roads road's Is Isto s sto to be constructed Is a firm and u unyielding ing foundation As s the quality of the soil oll has an important Influence on the proper method of at drainage and the type of of foundation to be employed much care and study must be devoted to the nature t type pe and and chara character Jer of the soils in the section through which it is to build a road Tile Tile- most mast Important primary soils are classified ns as gravel gra sand and clay but often ninny many of th the secondary or mixed soils solis lJ because enuse of their more genral general gen gen- er eral ral 1 occurrence In connection with road building operations are nrc equally Important Such t types rles as as main loam marl gumbo and are representative iwo tive of this order older In the design of ot a r road rand the drainage structures are planned t to take care of water general conditions rain rain that falls faUs on a It road surface or grade rain that falls faUs on contiguous land and flows flows in accumulated volume accumulated volume toward the road and gr ground und water from any immediate source To To meet these conditions use is found for special special spa spa- cial structures Including longitudinal s side e ditches es usually parallel or approximately ap proximately parallel to the center line Une intercepting ditches to accommodate water whose approach so so close to the roadway as as the side ditches is likely to cause injury lateral ditches or culverts culverts cul cul- cui- cui verts to conduct accumulated water away from or under the road and In In- order to o plan Intel Intelligently intelligently Intel intel- a system of ot drainage for tor any particular road It is necessary to con con- S iL S 55 5 5 y 55 ss Water Drains Readily Readily- From Typo Type of Highway sider not only the local character of ot th the soil composing the roadbed but also the topography of ot th the adjacent cent land the amount and rate of ot rainfall and the the- availability of material suit sulf- able for or use In in constructing drains Surface drainage systems for roads consist of side ditches s along the road paved gutters wl which are a development development develop develop- ment of side ditches and replace them open Intercepting Intercept ng ditches constructed to prevent water from reaching the road and lateral or or relief ditches hes to carry off ocr the water which which- collects In Inthe Inthe inthe the side ditches or In the intercepting ditches Culverts and drains which are constructed for the purpose of ot removing storm water from the side ditches or gutters are essentially a apart apart apart part of ot the surface drainage system and are not to to to-be to be confused with sub- sub drains which serve an entirely different differ dIffer- ent eat purpose Where the grade of a road Is Is' Isso so steep that the ordinary earth side ditches cannot be maintained satisfactorily satisfactorily satisfactorily at a reasonable cost or where earth side ditches would be or br appear unsightly It Is customary to i provide paved gutters for removing the surplus water Drop inlets and catch basins are areu u used ed to conduct water from side ditches ditch ditch- es as or r gutters Into underground drains I I I or culverts On country roads they are I used most frequently on side hill locations locations loca loca- I where where- the the- water collecting In the upper side ditch or gutter can be r removed re removed re- re moved from the road at Intervals by means of a culvert a across across ross to the lowen lower low low- er en side Drop Inlets usually ar are su dent elent and catch basins seldom are used In country road work except where It ItIs itIs Is especially desirable to prevent the slit silt and other foreign material carried by the water from getting Into the underground drainage structure |