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Specific Comments Page 13 regarding the results of the lishery investigations should indicate that no habitat modeling '.l.12oS conducted.. Only field meaS1J.r~m~nts ofwf":ttp.c1 wicith, .,r::le;e :lnrl depth were collected during the low now STUdy. With reference to the comment on the likelihood of crowding, no fish data was collected to determine if the populations are at a level where crowding would occur. This should be noted in the document. Fish abundance or tish population data would be the best means to determine relative abundance and densities of fish in certain habitat types. Conclusions regarding crowding due to changes in wened width are speculative absent that data. Comments on Anachment C. The data collected in the tishery STUdy mentions wetted perimeter as one of the pieces of data collected during the low now test. The descriptions of measurements taken during this STUdy show that wetted width was measured, not wetted perimeter. Welled perimeter is the distance along the channel bottom, not the surface of the water. These two measurements would be similar in rime habitat but in U-shaped channels, wetted perimeter can be very much different than welled width. All references to "welled perimeter'. should be corrected to read "wetted width.'. The threshold criteria for a significant impact in the EIS was a 20% change. The low flow test does not mention what level of change in a particular parameter would be considered significant. The conclusions of the tishery section state that change in wetted perimeter and average habitat depth did not result in direct mortality of fish. They do state that fish habitat is clearly reduced. Changes in wetted width are 14% or less for all cross- sections measured. It was not determined whether the reduction of approximately one-half foot of water depth from the 500 cfs level release to the 250 cfs level release was an impact to habitat. The relatively low percentage of wetted width change would indicate that there shouldn't be a large impact to primary and secondary productivity in the system. It is unknown whether this amount of change would impact fish habitat and fish species since no direct measure of fish abundance was collected during the test. Figure 3 on page 5 should have a new scale on the y-axis from zero to one in tenth of feet to better represent the water surface changes among habitat types. On the current scale it appears that there is a 50% change in water depth between rimes and run and pool habitat when in fact, it is 100th of a foot, a very small change in average depth between those habitat types. The change in scale would more accurately represent the actual change in water surface among all habitat types. Table 2 on page 6 shows average changes in water quality constiTUents. This table by itself does not add to the discussion on changes in water quality because there are different cold water and warm water fish species that use the full range of river where the water temperature, dissolved oxygen, conductivity and salinity were measured. The better representation to interpret changes in water temperature are in the figures 4 and forward that show the longitudinal change in temperature. It would add to the text ifnotes were placed on the sample sites as to which sites applied to trout habitat and which were warm water species habitat for better interpretation of the data. The importance of that demarcation is to determine if the 500 cfs flow and 250 cfs flow exceed parameters that would be lethal either on a chronic or acute level for the species of interest. There are conclusions regarding dissolved oxygen levels which assume that long term Comments Regarding the Summer low Flow Tests Bureau of Reclamation, November 2001 Miller Ecological CODsultants, Inc Page Z December 18,2001 ~~'f'l't