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<br />. <br /> <br />~ <br /> <br />. <br /> <br />t <br />f <br />. <br /> <br />2. Culvert Location. A culvert should <br />ideally be located in the existing channel <br />bed to minimize costs associated with <br />structural excavation and channel work. <br />However, this is not always possible. <br />Some streambeds are sinuous and cannot <br />accommodate a straight culvert. In other <br />situations, a stream channel may have to <br />be relocated to a void the installation <br />of an inordinately long culvert. When <br />relocating a stream channel, it is best <br />to avoid abrupt stream transitions at <br />either end of the culvert. Figure II-S <br />displays two examples of culvert location <br />procedures. (14) In one case, the culvert <br />follows the natural channel alignment. <br />In the second case, the channel has been <br />relocated to reduce the culvert length. <br />Brice concluded that minor channel relo- <br /> <br />. <br />, <br />, <br /> <br />t <br />, <br />I <br />. <br /> <br />t <br />f <br />, <br /> <br />t <br /> <br />. <br /> <br />, <br />, <br />~ <br />t <br /> <br />. <br /> <br />~ <br />~ <br /> <br />~ <br /> <br />) <br />) <br /> <br />. <br />, <br /> <br />~ <br />. <br />i <br />. <br /> <br />~ <br />~ <br />. <br />, <br />t <br />t <br />~ <br />. <br />~ <br /> <br /> <br />If. OF HIGHWAY <br /> <br />, <br /> <br />ALTERNATE <br />CULVERT <br />LOCATlON- <br /> <br />,t"",a <br /> <br />. <br />, <br />. <br /> <br />t <br />~ <br />t <br />t <br />~ <br />t <br />. <br />, <br />, <br />. <br /> <br />( <br /> <br />cations for culvert alignments have been <br />successful unless the natural channel <br />was already unstable. (15) <br /> <br />3. Waterway Data. The installation <br />of a culvert to convey surface water <br />through a highway embankment signifi- <br />cantly constricts the flood plain. To <br />predict the consequences of this altera- <br />tion, accurate preconstruction waterway <br />data must be collected. These data in- <br />clude cross-sectional information, stream <br />slope, the hydraulic resistance of the <br />stream channel and floodplain, any condi- <br />tion affecting the downstream water sur- <br />face elevation, and the storage capacity <br />upstream of the culvert. Photographs of <br />site conditions are often beneficial. <br /> <br /> <br />\, <br /> <br />RELOCATED \ <br />CHANNEL-' " ' d" , <br /> <br />Y <br /> <br />Figure II-S.--Culvert location methods. <br /> <br />~ <br />. <br />. <br /> <br />19 <br />