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Fall: Winter: Spring: Summer: October, November, December January, February, March April, May, June July, August, September Significance of differences between seasons and sites was determined by analysis of variance and least significant difference. RESULTS AND DISCUSSION PHYSICAL PARAMETERS Three type of illustrations are used to depict changes in the river over time: (l) a series of plan view maps show how the river meander, water current, and gravel bars shifted during the study; (2) cross sections at particular locations depict changes in the stream bottom after varying lengths of time; and (3) thalweg profiles record how the longitudinal profile changed over time. The following discussion requires reference to plan view maps to establish the location of cross sections and the meander of the river in the study area. Distances along stream reaches are recorded in meters, and stations (cross sections) are identified by their position (in meters) along the reach. General Changes in ~tream Meander, Water Current and Gravel Bars Stream length can be expressed by two measurements: (1) The centerline length of the stream, and (2) the thalweg length that follows the deepest part of the channel. A straight channel would produce a ratio of thalweg to center- line length of one while a meandering channel would produce a ratio of more than one. Only one major change can be noted between November, 1972 and 1975 at Logan bulldozed site (Figure 12). A pool with depths of greater than 1 m developed between stations 46 and 137, and a large gravel bar was deposited on the convex side of the river bend in the same area. Development of the pool was accompanied by erosion of the bank 011 the concave side, a process which prompted the landowner to use a bulldozer to remove the gravel bar to fill in the pool and shift the western bank some 5.2 m further east. Between r1ay and November, 1975, most of the 1975 alteration had been restored to pre-alteration condition. This does not imply particularly good conditions, since only 8 percent of the site length contained pools of 1 m depth or greater. Examination of the plan view maps (Figure 13) discloses several changes which took place at the Blacksmith dredged reach during this study. As mention- ed in the discussion of cross sections, dredging usually removed streambed materials along convex banks, and the river subsequently relocated the streambed to the same general locations. Dredging usually widened the river, but deposi- tion later usually returned the stream to near its original width. The numbers and sizes of pools are of interest because of the importance to fish (Table 1). Note that both the number of pools and total linear meters of pools more than one m deep decreased after each dredging. Spring runoff in 1975 not only 21