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<br />on 0585. <br /> <br />SUmmary of Performance Index <br /> <br />The Performance Index is a reasonable formula to evaluate whitewater or boating <br />course potential. The Performance Index is a product of the percentage slope and the <br />discharge for the RICD in question: <br /> <br />PI=((Hydraulic Drop/Boating Course Length) x Discharge) x 100 <br /> <br />Where: <br />The variables Hydraulic Drop and Boating Course Length are measured in the same units <br />(i.e. feet), and Discharge is measured in cubic feet per second (cfs). <br /> <br />Hydraulic Drop is the difference (in feet) between the water surface elevation just <br />upstream of the upstream control point and the water surface elevation at the <br />Downstream Section of No Hydraulic Impact. <br /> <br />The Boating Course Length (in feet) is defined along the RICD stream reach centerline <br />starting at the most upstream control point and continuing through the most <br />downstream control point that enhances and defines the RICD reach. Furthermore, the <br />Downstream Cross-Section of no Hydraulic Impact defines the downstream terminus of <br />the Boating Course Length. <br /> <br />Downstream Section of No Hydraulic Impact is defined as the stream cross-section at <br />(or just downstream of) the RICD reach where river and hydraulic parameters such as <br />velocity, shear stress, channel width, channel depth, sinuosity, etc. are first returned to <br />the pre-project state. <br /> <br />The Performance Index has several advantages as it can determine the potential of an <br />undeveloped site and a developed site on an equal basis. It does not rely on subjective <br />judgments regarding the average conveyance width. <br /> <br />The Performance Index takes into consideration enhancing hydraulic head by impounding <br />water at the start of the course in order to achieve more drop. The Performance Index <br />can be easily verified by field measurement and by computational hydraulics. <br /> <br />A Performance Index of 75 is considered as a minimum threshold of "a reasonable <br />recreational experience" for a destination-oriented boating course whereas a higher <br />index number such as 500, for example, can be considered to have "world class" <br />potential. As explained below, these numeric values reflect the Performance Indices <br />that exist at "pay for" courses. <br /> <br />11 <br />