. Alaska forest research : problems and present status : annual report, 1955. Forests and forestry Alaska. The volume deterrnination shows clearly the unstable nature of the inter- tidal zone in terms of cubic yards of material moved during a typical winter period. Five hundred fifty-six cubic yards of material were moved in a 200-foot section between July 1953 and July 1954. An examination of nine cross sections vmiformly spaced over the study area shows that deposition which occxirred in the reach between stations 0 4 00 and 2 4 00 was typical of the other cross sections also, A total net vo
. Alaska forest research : problems and present status : annual report, 1955. Forests and forestry Alaska. The volume deterrnination shows clearly the unstable nature of the inter- tidal zone in terms of cubic yards of material moved during a typical winter period. Five hundred fifty-six cubic yards of material were moved in a 200-foot section between July 1953 and July 1954. An examination of nine cross sections vmiformly spaced over the study area shows that deposition which occxirred in the reach between stations 0 4 00 and 2 4 00 was typical of the other cross sections also, A total net volume of approxiinately 4,100 cubic yards of material was probably moved over the 1375 lineal feet of stream included in the study. The apparent high sensitivity of the Harris River-Indian Creek intertidal zone to the actions of scouring and deposition make it an excellent area in which to study this phase of the investigation. The cross sections in this area will be remeasured yearly to determine whether a significant change occiirs after logging begins on the Harris River watershed. Sedimentation Erosion material alters the environment of fish in a number of different ways and is generally recognized as harmful to fish populations. One of the most important effects is the blanketing of salmon beds with heavy silt \>rhich causes mortality to the buried eggs by retarding the free circulation of dissolved oxygen to the salmon spawn. Other changes include (l) creation of unfavorable stream bottom conditions by the retention of organic material and other substances, (2) alteration of temperature change rates, and (3) screening out light. Silt may limit the available food supply. Several studies have been made by Fisheries men which offer rather con- clusive evidence that heavy stream siltation may cause severe mortality of salmon eggs and Figure 13.—Discharge measurements can be made by wading when water is at normal level, feybeso Creek, 38 -. Please note that these
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