Laserfiche WebLink
<br />. <br /> <br />All culverts and bridges are evaluated for the fol- <br />lowing characteristics:' <br /> <br />o <br /> <br />Propensity for reduced conveyance capacity due to <br />debris blockage <br />Damming effect die to undersized structures <br />Diversion of flood flows of washout of structures <br />die to the above characteristics <br /> <br />o <br /> <br />o <br /> <br />. <br /> <br />The potential for blockage of structures and subse- <br />quent reduction in conveyance is based on watershed <br />characteristics such as erodibility of channel <br />banks, amount and type of vegetation along the <br />stream, and size and character of the waterway. <br />Blockage may be artificially accounted for by <br />increasing the width of bridge piers, raising the <br />streambed elevation or reducing the waterway opening <br />by a percentage in the hydraulic calculations. <br /> <br />-25- <br /> <br /> <br />. <br /> <br />Those floodwater surface elevations are portrayed in <br /> <br /> <br />the report in two ways. First, flood profiles show <br /> <br /> <br />the relationship of the water surface elevations to <br /> <br /> <br />the channel bottom at a particular point along the <br /> <br /> <br />stream in a pictoral representation (see Figure _). <br /> <br /> <br />Second, a reference table shows elevations at each <br /> <br /> <br />floodplain cross-section used in the study in a <br /> <br /> <br />numerical representation. <br />