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<br />v <br /> <br />" <br /> <br />0015~5 <br /> <br />l <br />~ PROPOSED PHASE II PROCEDURE <br /> <br />I. PRELIMINARY ASSESSMENT OF QUANTIFICATION SITE <br /> <br />A. Locate point on USGS 7.5-minute quadrangle map. <br /> <br />B. Determine average channel gradient, mean basin elevation, and <br />watershed area. <br /> <br />C. Assign preliminary stream classification according to Rosgen <br />(1985). <br /> <br />D. Obtain and review historical aerial photography, if available, to <br />aid in stream stability, vegetation, and geologic evaluation. <br />Historical aerial photography can aid in identifying and assessing <br />historical changes in channel plan form and width, bank erosion, <br />and vegetation encroachment (or loss). <br /> <br />II. FIELD DATA COLLECTION <br /> <br />A. Perform general reconnaissance of stream reaches upstream and <br />downstream of the quantification point to evaluate the variation in <br />stream classification, bed and bank material, natural or man-made <br />controls, vegetation, gradient, width, bank erosion, channel bar <br />formation, etc. The reconnaissance should extend sufficiently far <br />up- and downstream of the quantification point to insure that the <br />selected study reach is representative of the stream characteris- <br />tics. <br /> <br />B. Eval uate the need for maintenance flows based on stream charac- <br />teristics. If the gradient of the controll ing reach of stream is <br />steeper than four percent (i.e., Class A stream) and field <br />reconnaissance indicates that the bed is significantly armored with <br />cobble- and boulder-sized material, perform only the investigations <br />listed in Task F.I-3 to determine if there is potential for <br />vegetation encroachment. For Class A streams: <br /> <br />1. If it is determined that 1 ittle potential for vegetation <br />encroachment exi sts, no maintenance flow is requi red. No <br />further investigation is required. <br /> <br />2. If potential for vegetation encroachment exists, perform only <br />Task IV, Item G. <br /> <br />C. Collect the following topographic information: <br /> <br />1. Identify and survey 3 to 5 cross sections, spaced at 100- to <br />500-foot intervals which will adequately reflect the hydraulic <br />geometry of the stream in the study reach. <br /> <br />2. Monument each section for future reference. Establish <br />relative elevations of section monuments using level loop. <br />