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Appendix D — SOP for Stream Flow Measurement — Hansen Project 18 <br />SURFACE WATER DATA COLLECTION FIELD NOTE <br />DISCHARGE MEASUREMENT NOTES <br />Date: 120 <br />Width: <br />Method: <br />Site No. <br />Measurement No. <br />Comp. By <br />Checked By <br />Team Station No. <br />Area: Velocity: Flow (cfs): <br />Type of Meter: Gage Height: <br />Wading, upstream, downstream from bridge and <br />Spin: Before After <br />Record Removed <br />Comments /observations: <br />feet above, below station marker, gage. <br />Control: <br />Measurement Rated: [(Excellent (2 %), Good (5 %), Fair (8 %), Poor (over 8 %)] Based on following conditions: <br />Cross Sei <br />Flow: <br />Weather: <br />Other: <br />Figure 4. Example Surface Water Data Collection Field Notes <br />3.2. S Discharge Calculations <br />A stream discharge is the summation of the products of the subsection areas of the stream cross section and <br />their respective average velocities. The formula <br />Q = Y—(av) <br />represents the computation, where Q is the total discharge, a is an individual subsections' area, and v is the <br />corresponding mean velocity of flow normal to the subsection. The summation of the discharges for all the <br />subsections is the total discharge of the stream. The order for calculating discharge is: <br />Use the distances from initial point recorded on the measurement notes (Figure 3) to compute <br />width for each section. The first width is computed by subtracting the first distance from the <br />second distance, and dividing this quantity by two. The second width will be the quantity of <br />difference between the third distance and the first distance, divided by two. For each subsequent <br />width, subtract the distance on the line above the line you are calculating from the line below, and <br />divide this quantity by two. This procedure is carried out for each line until you reach the final <br />4153A.140129 Whetstone Associates <br />