generally contain and dispose of all the runoff.However, during the winter in the high mountains,runoff is commonly interrupted by snow conditions;that is, instead of running off, the potential runoffaccumulates in the form of snow. When thisaccumulated mass melts in the spring, the runoff oftenattains proportions that overwhelm the naturalchannels, causing flooding of surrounding areas. Inthe same fashion, unusually heavy rainfall mayovertax the natural channels.Artificial Drainage.— When artificial structuresare introduced into an area, the natural drainagearrangements of the area are upset. When, forexample, an area originally containing many hills andridges is graded off flat, the previously existing naturaldrainage channels are removed, and much of the effectof gravity on runoff is lost. When an area of naturalsoil is covered by artificial paving, a quantity of waterthat previously could have been absorbed will nowpresent drainage problems.In short, when man-made structures, such asbridges, buildings, and so forth, are erected in an area,it is usually necessary to design and construct anartificial drainage system to offset the extent to whichthe natural drainage system has been upset. Stormsewers are usually the primary feature of an artificialFigure 10-1.—Working drawing for a typical curb inlet.10-4
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business