Opinion ID: 355551
Heading Depth: 2
Heading Rank: 2

Heading: Remnant Channels.

Text: 101 The defendants rely on evidence of remnant channels in the Blackbird Bend area as a common phenomenon associated with the progressive and gradual movement of a channel as a result of accretion. However, this evidence was proffered only as a possible alternative explanation to the plaintiffs' evidence that the remnant channel areas demonstrated avulsive changes in the thalweg. 48 102 The evidence further reflects that Dr. John F. Kennedy testified that, as the thalweg shifted to the west, the low energy level of the river in the former channel created by the movement would result in deposition there. The defendants conclude from this that the shift in the river was a consequence of progressive scour and deposition. The testimony of defendants' expert, Dr. Kennedy, showed, however, that the shift of the thalweg is often the responsible agent for the subsequent diminished sediment transport capacity of the water. Thus, the testimony is inconclusive as to whether the remnant channel was formed by accretion or avulsion since a remnant chute might also have been formed after the thalweg suddenly and perceptibly moved. In the latter case the deposition forming the remnant channel would be the effect of the low river energy in the area brought about by the sudden avulsive shift of the thalweg rather than a consequence of accretion. As the Supreme Court observed in Arkansas v. Tennessee, 246 U.S. at 175, 38 S.Ct. at 305, 103 if the stream leaves its former bed and establishes a new one as the result of an avulsion, the boundary remains in the middle of the former channel. An avulsion has this effect, whether it results in the drying up of the old channel or not. So long as that channel remains a running stream, the boundary marked by it is still subject to be changed by erosion and accretion; but when the water becomes stagnant, the effect of these processes is at an end; the boundary then becomes fixed in the middle of the channel as we have defined it, and the gradual filling up of the bed that ensues is not to be treated as an accretion to the shores but as an ultimate effect of the avulsion. 104 (Emphasis added). 105 None of the explanations for the remnant channels are, however, more than sheer conjecture and do not, under the factual circumstance shown here, constitute probative evidence of whether the movement occurred by either accretion or avulsion. 49 106