Although occasional gravel removals might 

 cause only a slight decrease in a stream's poten- 

 tial productivity, experience has shown that com- 

 plete spawning grounds may be lost if removals 

 are carried on indiscriminately and on too large 

 a scale. Siltation normally accompanies any re- 

 moval operation in a greater or lesser degree, 

 and the fine silt particles that are washed down- 

 stream impair percolation of water through the 

 gravels and tend to smother both eggs and fry. 

 Heavy equipment used on the stream bed during 

 removal operations frequently crushes the eggs 

 and fry. Merely the activity of the operation it- 

 self and the resultant turbidity prevents adults 

 from spawning. More permanent effects are pro- 

 duced when large portions of the actual spawning 

 beds are removed. In addition, fish might be 

 blocked from reaching long stretches of spawning 

 area as a result of dewateringor diversion asso- 

 ciated with gravel excavation. 



Examples of the effects of indiscriminate 

 removal of gravels are conspicuous in a group of 

 streams on the northeast side of Kodiak Island 

 (figure 2). These streams, Russian River , Kalsin 

 and Sargent Creeks, an unnamed stream which 

 flows into Anton Larsen Bay, and a tributary of 

 BuskinLake, historically supported valuable runs 

 of pink and chum salmon and Dolly Varden char. 

 Some of them also contained runs of red and silver 

 salmon and steelhead trout. During World War II, 

 it became necessary to construct numerous build- 

 ings, airport runways, and an extensive network 

 of roads. Great amounts of gravel were required, 

 and the most expeditious method of obtaining it 

 was by removal from stream beds. Owing to the 

 emergency situation, there was little considera- 

 tion given to the fishery values. Entire stretches 

 of stream beds were removed to depths of 20 feet, 

 and at some locations the tailings and silt from 

 the washing and screening were permitted to re- 

 enter the stream channel. 



Large stretches of spawningbeds were re- 

 moved in Russian River (figure 3) and Sargent 

 Creek. The re-entry of tailings from washing 

 and screening processes so reduced the average 

 size of the stream gravels that the stream bed is 

 now unstable and the channel pattern shifts re- 

 peatedly. As a result, the fish-producing poten- 

 tial has been reduced. 



The effects on the tributary of BuskinLake, 

 the east fork of Kalsin Creek, and the unnamed 

 stream entering Anton Larsen Bay were of a dif- 

 ferent nature. In these, streambottom materials 

 for distances up to 2 miles above the removal site 

 broke up and were washed downstream. Natural 



layering of the silt, sand, and gravel was com- 

 pletely disrupted. As a result, stream flow was 

 limited to subterranean seepage in the "slipped" 

 area during periods of low water. Without sur- 

 face flow these sections had no value as spawning 

 grounds and, in addition, fish were not able to 

 reach the large areas of spawning gravels farther 

 upstream. Several miles of excellent spawning 

 grounds were rendered completely inaccessible. 

 This is believed to be relatively permanent since 

 the removals described took place largely before 

 1944, and the gravels of only one of the streams 



that which enters Anton Larsen Bay have 



shown signs of stabilization since that time. Re- 

 deposition of the layer of silt that prevents sub- 

 terranean flow is largely dependent on the silt 

 load carried by the stream. Thus, complete re- 

 covery in these clear waters will require many 

 years. 



It is possible that the decline in the fish 

 runs of these streams could be the result of fac- 

 tors other than gravel removals; however, the 

 streams where the decline was most severe were 

 Russian River and Sargent Creek, both of which 

 were subjected to extensive removal operations 

 for several years. Salonie Creek flows into the 

 same bay and is comparable in many respects 

 with these streams, but only minor amounts of 

 gravel were removed from here and the fish runs 

 have remained at a high level. A similar com- 

 parison between the two forks of Kalsin Creek 

 reveals that fish runs of the east fork from which 

 large amounts of gravel were removed have de- 

 clined markedly, while those of the west fork, 

 which was subjected only to very limited removal 

 operations, have remained in good condition. 



Although the undesirable effects of a single 

 gravel removal project may seem insignificant in 

 relation to the total Alaskan fishery resource, the 

 aggregate effect of several projects is extremely 

 significant. For this reason, the Bureau of Com- 

 mercial Fisheries reviews each proposal for re- 

 moval of stream gravels that is brought to its 

 attention. Responsibility for this work rests with 

 the Branch of River Basin Studies, which operates 

 under the authority of the Fish and Wildlife Co- 

 ordination Act. In Alaska, this Branch presently 

 maintains a permanent staff of four biologists in 

 Anchorage and three in Juneau. 



For information concerning gravel removal 

 projects, the Branch of River Basin Studies relies 

 on the District Management offices of the Bureau 

 of Commercial Fisheries, the Bureau of Sport 

 Fisheries and Wildlife, and on the three Federal 

 agencies that arrange and administer gravel sales 



I 



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