2014-01-29_HYDROLOGY - P2009025 (8)

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Appendix D — SOP for Stream Flow Measurement — Hansen Project 15 affected by the scoured depressions left by the hydrographer's feet. For such streams, the meter should be placed ahead of and upstream from the hydrographer's feet. Once the velocity -area measurements have all been taken, measure and record the gage height from the staff gage to the nearest 0.02 foot again. Steps to be Followed in Measuring Discharge. Water quality and bed material samples will be collected prior to making discharge measurements. The following steps are to be followed in discharge measurement: 1. Use the staff gage to measure and record the gage height to the nearest 0.02 feet. Measurement notes are recorded as indicated in Figure 3 at each subsection of the cross section as the measurement is performed. After the measurement is completed, the data outlined in Figure 4 are filled out. If two people are performing the measurement, the hydrographer may state the stations, depths, counts, and number of seconds to a note keeper. The note keeper would then repeat each value stated by the hydrographer to ensure agreement between the value stated by the hydrographer and the value heard by the note keeper. 3. Record in the fieldbook the following: distance from initial point, width, depth, observation depth, revolutions, time in seconds, velocity, area, discharge. 4. Note the distance in feet in terms of stream direction that this cross section rests from the prescribed location. For example, the note may read "25 feet downstream" or "15 feet upstream." This is recorded in a manner similar to that for the discharge measurement (Figure 3). 5. Several measurement locations are required from one side of the stream to the other. Select the approximate number of subsections at which to take measurements as listed on Table 3. Position a tape (for small streams) or the tagline (for large streams) about one foot above the surface of the water. Secure the tape so that it remains taut and perpendicular to the channel. 6. Select a starting point at either the left bank (left edge of water, River Left, RL) or the right bank (River Right, RR), which is determined by facing downstream. Measure the width of the stream in feet. After selecting the Price AA or Pygmy meter, follow Table 3 to select the number of subsections in which to measure velocity. The goal in selection of measurement stations is to measure no more than 10 percent of the total discharge in any given subsection. Subsections need not be identical in width. Use more observation points in deep areas or portion of the channel having higher velocities. Frequently, fewer observation points are needed near the shore than near the center of the stream. 8. After determining the distance desired between stations, measurement can begin. Record the time and bank at which measurement starts on Figure 3 as "RR Start 0000 ", using river right (RR) or river left (RL), depending upon whether starting at the right or the left edge of the water when facing downstream. 24 -hour clock time is used, and is recorded to the nearest five minutes. 9. Note the distance to the beginning edge of water from the initial point. The initial point is an arbitrary point on the tape, preferably a whole number, which lies on the shore of the stream. All subsequent station locations are recorded as distances from the initial point. 10. Proceed to the first station. Record the distance from the initial point on the discharge note. 11. Stand downstream of the tagline or tape and face upstream. Begin with the current meter on the wading rod well above the surface of the water. 12. Measure stream depth at the measurement point on the wading rod. Individual lines on the wading rod indicate 0.10 -foot increments; double lines indicate 0.50 -foot increments, and triple lines indicate 1.00 -foot increments. Record the stream depth to the nearest 0.02 feet: for example 0.32 feet or 1.54 feet. 4153A.140129 Whetstone Associates