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<br />I <br />l_ <br />/ ):t\ <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I" <br />I <br />I <br />I <br />I <br />I <br />I' <br />I <br /> <br />0\ <br /> <br />1.1 <br />I <br /> <br />4. The quantity of debris at the site will be minimal and the slte <br />does not have a history of colle~ting debris. <br /> <br />5. The channel will be relatively unlform upstream and oownstream <br />from the bridge site. <br /> <br />6. The site will be accessible during high flows. <br /> <br />7. Br idges will be wide enough to pI'ovide safe 'wor" space for a <br />two-person crew and the measuring equipment. <br /> <br />8. Contraction of the channel at the bridge site will be minimal. <br /> <br />9. Preferably, a satellite or telemeter station will be at the <br />site or nearby for monitoring of discharge. <br /> <br />Site Establishment and Initial Data Collection <br /> <br />Initial data collection and site preparation will include: <br /> <br />1. Establishing permanent elevati~n reference marks at the a~proach <br />cross section to the bridge, at the bridge, and at some distance <br />downstream of the bridge. <br /> <br />2. Surveying cross sections at the approach section and along the <br />upstream side of the bridge, including scour depths in front of <br />and close to the sides of the piers. <br /> <br />3. Defining bridge, pier, and upstr'eam and downstream ~hannel geometry. <br /> <br />4. Marking the bridge railing permanentiy Cor stationing distance <br />and points to measure scour near piers. <br /> <br />5. Taking photographs of the bl'idge opening and the upstream and <br />downstream channels with and without vegetation cover. <br /> <br />6. Collecting bed-material samples in scour holes and along the, <br />cross section on the upstream side of the bridge fur a bed-materlal <br />statistical size distribution. <br /> <br />7. Installing wire-weight gages or staff gages (to manually read <br />stage) and hiring observers at sites that are not at or near USGS <br />streamflow-gaging stations to assist in eCficient data collection. <br /> <br />8. Installing telemetry equipment at up to 5 USGS streamfiow-gDging <br />stations that are not originally equipped with telemetry equipment. <br /> <br />A-5 <br />