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<br />14 <br /> <br />1981 . <br /> <br />During 1982, a different ill unlinance meter was used which <br /> <br />read directly in luxes and could be taken underwater by the <br /> <br />diver. <br /> <br />Surface 1 ight was measured at the water surface. <br /> <br />Macrohabitat was defined using a series of common subjective <br /> <br />- <br /> <br />term~ referring to stream habitat. These terms incl uded mid and <br /> <br />side pools, glides, back-eddies, rapids and riffles. <br /> <br />Many of these variables were redundant or appeared to be un- <br /> <br />important in defining microhabitat for the two study species. <br /> <br />The six most pertinent variables which will be discussed in this <br /> <br />report are fish and mean column velocity, fish and water depth, <br /> <br />substrate type, and overhead light. Summary tables of these var- <br /> <br />iables are presented in an appendix volume for modeling purposes <br /> <br />bY USBR personnel. The nearest thigmotactic surface was essen- <br /> <br />tially the same as fish depth since the river bottom was usually <br /> <br />the nearest thigmotactic surface. <br /> <br />Vegetative cross sections <br /> <br />if, <br /> <br />Vegetative cover was measured in the intensive study area. <br /> <br />The same transects (Figure 2) were utilized as had been esta- <br /> <br />bl ished by USBR personnel for the IFG-4 hydraul ic model. <br /> <br />A cable calibrated in 1.5 m intervals was attached to the <br /> <br />starting post on the north side of a cross section. A diver then <br /> <br />unreeled the cable along the stream bottom to the south side of <br /> <br />the cross section. <br /> <br />A surface observer kept the diver in line <br /> <br />with the stakes on the south shore. The diver transmitted to the <br /> <br />surface personnel: substrate type; plant species (if any); per- <br /> <br />cent density of plant cover along the transect; water depth; and <br />