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<br /> <br />more preferred mean column velocities and "acceptable" depths. <br /> <br />hood, this flow may result in a reduction in cover (e.g. water depth, s <br /> <br />banks, overhead vegetation), reduction in water quality, or elevated <br /> <br />temperature. <br /> <br />This suggests not necessarily a problem with the model but with the pre" <br /> <br />ference curves. The IFG urges users to develop their own preference curves for <br /> <br />each fish species and stream. This is, no doubt, the best source of curvesj <br /> <br />h?wever, it is largely impractical because of associated time and money <br /> <br />constraints. For this model to assume pract~cality for most fishery biologists, <br /> <br />it is important that the burden of building curves be minimized. One possible <br /> <br />solution might be to develop curv~s in all cases for all life stages of sen- <br /> <br />sitive species. <br /> <br />For more common species, curves might be developed only for <br /> <br />large and small streams by combining data from several streams in each category. <br /> <br />Though not addressed in this paper, these curves would probably only need to <br /> <br />be developed for adult, juvenile, and fry life stages. We feel that existing <br /> <br />curves for spawning and incubation life stages of most species are reasonably <br /> <br />accurate. <br /> <br />Because these forms are imfobile, col1ectio~ of field data is more <br /> <br />consistent and hydraulic conditions are more accurately rep~oduced in laboratory <br /> <br />settings. <br /> <br />11~~ <br /> <br />MANAGEMENT CONSIDERATIONS <br /> <br />Instream flow methods ,may take either of two forms. By far, the majority of <br /> <br />the methods generate what! may be termed threshold or baseline recommendations. <br />I <br /> <br />This kind of recommendation formed ~he baSis upon which methods were compared in <br /> <br />this $tudy and includes any method that generates a single-flow recommendation. <br /> <br />13 <br /> <br />It <br /> <br />.~ <br />