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r <br />G.2.2 Flow Data Collection <br />j Three surface water gaging stations were established in <br />November 1987 (RS-1, RS-2 and RS-3; see Figure G-1). As <br />preliminary site development plans evolved, additional gaging <br />stations were added in the spring and summer 1988 to provide <br />monitoring of the project area (RS-4, RS-5 and RS-6; see Figure <br />G-1). <br />Each gaging station consists of a staff gage and a rated <br />section. Each section was surveyed when established, with <br />' benchmarks placed on either side of the channel to tie the <br />section to known elevations. The sections will be resurveyed, <br />as necessary, when large changes in the channel geometry occur. <br />In addition to monitoring flow at each of the gaging stations, <br />each gaging station is equipped with two U.S. Geological Survey <br />' U-59 single-stage sediment samplers (Federal Inter-Agency <br />Sedimentation Project, 1961). The samplers are located at <br />different heights to allow sampling at two separate stages of <br />flood events. The creek stage where each of the single-stage <br />sediment samplers will sample is shown in Table X1.2-1. <br />Surface water flows at each of the six gaging stations <br />i . are obtained through weekly readings of the staff gage at each <br />station during base. flow conditions. During the period of <br />spring runoff, daily flow measurements are recorded from the <br />staff gage. <br />Staff gage readings were converted to flow measurements <br />at each of the gaging stations by the development of a <br />theoretical rating curve from the surveyed cross-section. The <br />' theoretical rating curves were developed by using Manning's <br />equation, inputting an estimate of the roughness coefficient <br />(n) for each of the stations. These theoretical rating curves <br />are being corroborated through actual flow measurements with <br />a current meter. Because significant fluctuations in the stage <br />1 G-11 <br />1 <br />