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<br />32 <br /> <br />Time and Cost Analysis <br /> <br />A total of 56 days over a 7-month period was needed to <br />collect the field data. Out of a total of 930 man-hours ex- <br />pended for data collection, 447 man-hours were for travel time <br />and 483 hours were for actual collection of data. This breaks <br />out at 48% for travel time and 52% for data collection. Without <br />a good analysis of gaging histories prior to collecting any field <br />data the ratio could easily have been 60% to 40% in favor of <br />travel time or even worse. <br /> <br />Table 17 presents labor costs (for travel time and data <br />collection time only) for a single cross section for all 18 <br />study areas. These data indicate that ,the cost per cross section <br />increases in direct proportion to stream width UD to app-ro~imat:;.ely <br />30 feet. From 30 feet to about 60 feet in stream width the <br />. cost per transect is essentiallv constant with the cost j!gain <br />rising for. streams up to 100 feet in wid th or more. 1:his is <br />solely the result of the type and amount of data needed for a <br />cross section. The Instream Flow Service Group (IFSG) recommends <br />,a minimum of 20 to 30 data points (depth, velocity_~~?ub- <br />~trate) be collected for each transect. but at no smaller intervals <br />than 1-foot incr~m~nts. Therefore, for streams up to 30 feet <br />in width the time required for collection of field data is purely <br />proportional to the transect width. Streams from 30 to 60 feet <br />in width are evaluated in 2-foot increments; thus, the number <br />of data points required remains at 20 to 30 per transect and <br />the field time and costs are constant. The IFSG does not feel <br />it is necessary to have more than 30 data points even for a <br />stream of 200 feet in width as much additional data does not <br />significantly improve the computer evaluation of the transect. <br />However, this type of data collection requires a field crew <br />well versed in the mechanics of stream hydrology to insure that <br />the data collected is truly representative of the stream cross <br />section. To eliminate this variable and potential serious <br />sources of error resulting from subjective judgment, streams <br />40 feet in width and greater were always evaluated in 2-foot <br />increments. \~ile this may have resulted in some waste of time <br />and effort in the eyes of the IFSG, it was a wise decision as <br />insufficient data can greatly compromise the precision and <br />accuracy of the computer output. Since almost 50% of the time <br />,is fixed as travel time, a doubling or even tripling of the <br />number of data points does not add much to the total cost of the <br />entire evaluation process. <br /> <br />To more accurately estimate costs for travel time, field <br />data collection time, and per diem expenses, three of the 15 <br />study streams were selected for a more detailed analysis. These <br />three streams, the Lake Fork of the Gunnison, South Fork of the <br />Rio Grande, and the Williams Fork rivers were chosen for the <br />following reasons: <br />