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<br />001877 <br /> <br />32.3--2 <br /> <br />WATER INFORMATION MANAGEMENT SYSTEM HANDBOOK <br /> <br />A. Steo 1. <br /> <br />1. Secure the following data from the representative gage <br />station and all suitable gage stations. Some of these data will <br />require collection in the field if unavailable from station <br />records. <br /> <br />a. Hydraulic geometry and related discharge. <br />b. Stage-discharge relation. <br />c. Channel cross sectional area at bankfull stage (and <br />baseflow stage for the representative station). <br />d. Water surface slope at bankfull stage. <br />e. Wetted perimeter, hy~raulic radius, and roughness (if <br />Manning's equation is used to estimate discharge). <br />f. Field-measured bankfull discharge, if feasible. <br /> <br />2. Secure for the representative gage station the <br />following. <br /> <br />a. <br />record. <br />b. <br /> <br />Duration table of daily values summary for the period of <br /> <br />c. <br /> <br />Mean annual discharge. <br />Daily mean hydrograph data for period of record. <br /> <br />B. Steo 2. Determine bankfull discharge and baseflow for the <br />representative gage station. Using either field measurements of <br />discharge or hydraulic geometry relations (or cross-sectional <br />area data) with the stage-discharge curve from the representa- <br />tive gage station, determine the discharge at the bankfull <br />(Q ) stage. Using depth ratios, stage, or cross sectional <br />arRa determine discharge at the baseflow (Q ) stage. (Note: <br />Baseflow stage is the water surface elevatihJ associated with <br />the discharge that just fills the thalweg or inner berm <br />channel.) <br /> <br />C. Steo ~. Collect data at all suitable gage stations. <br />Calculate or measure bankfull discharge as described in step 2. <br /> <br />D. Steo 4. Develop general relationship. From the data of the <br />representative and all suitable gage stations and using an <br />appropriate statistical technique, develop the following <br />relationship. <br /> <br />QB = <br /> <br />x <br />kA sY <br />B <br /> <br />where, <br />QB = <br />AR ~ <br /> <br />k,x,y = <br /> <br />bankfull discharge, <br />channel cross-sectional area at <br />water surface slope at bankfull <br />constant and exponents. <br /> <br />bankfull stage, <br />stage, and <br /> <br />*-FSH 4/89 AMEND 3-* <br />