128 



\ ji 



centimeters. Mortality dropped quickly at depths greater than 23 centimeters. | 



To put this in perspective for we nonscientists, 23 centimeters equals 9 inches. ( 

 The study's conclusion suggested that "limiting jet boat use (size and intensity) jj 

 may be warranted in shallow, constricted stream channels where the potential !| 



for substrate disturbance is high." They recommended that any restrictions to j 



be placed on jet boating be on a case by case basis, taking into accoimt site- |: 



specific conditions. i 



According to a monitoring report by Forest Service biologist Al Mauer, the r 

 1994 Fish and Wildlife Service survey of Fall Chinook saknon redds found 10 j; 

 redds in the HCNRA portion of the Snake River that were located where they 

 could be affected by jet boats. These varied in depth from 6 to 1.3 meters; that 

 is from 19.7 to 4.3 feet. They averaged 2.1 meters or 7 feet deep. None of the 

 redds were shallow enough to warrant marking to help boaters avoid them. The 

 conditions are not even close to those defined in the Alaska study as justifying 

 jet boat restrictions. 



Nothing in the fisheries sUidies done to date to indicate any impact by jet 

 boating in Hells Canyon upon salmon. It is likely that fast moving jet boats 

 cause less disturbance to adult fish than nonmotorized craft, their behavior more 

 closely resembling that of predators salmon have leamed to avoid. The finding 

 of no adverse effects is clearly appropriate for Hells Canyon. 

 Beaches 



Hells Canyon used to be notable for its many expansive sand beaches. 

 Today, however, most are gone. A few upper river beaches in particularly 

 favorable locations survive, and even recruit new sand in high-water years. 

 Below the Imnaha and Salmon Rivers we still enjoy many beautiful beaches, 

 but even these are much reduced in number and size from their historic level. 

 So, what has happened? Are these important components of a wild river 

 environment the victims of power boat wakes as some would have you believe? 



First of all, lets take a good look at beaches and how they are formed. Sand 

 beaches in a free flowing river environment are dynamic things, forever 

 changing with shifts in the river's bed, eddies and currents. In the spring, as 

 water rises, it gains energy with spring snow melt and sand begins to move 

 downstream. Existing beaches are eroded away and new sand is recruited from 

 the tributaries, river bed and upstream beaches. As the runoff wanes and its 

 energy drops, sand begins to settle in the eddies and pockets along the river's 

 edge, rebuilding the beaches. This cycle of erosion and deposition has gone on 

 for as long as we have had a river, that is imtil dams were built up stream. 



Brownlee, Oxbow and Hells Canyon dams serve as gjgantic sediment traps, 

 capturing sand that would have renewed beaches. The day that Brownlee began 

 holding water, the fate of Hells Canyon's beaches was sealed. Since the three 



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