Second in a series on water boundaries.
Water boundary principles are easy to state in the abstract but difficult to apply in practice. The usual way to analyze how a particular legal rule applies to a situation is to consider the reason for the rule and determine whether that purpose is furthered by applying it in the instant case. For example, a rule states that monuments control courses in a description. When you think about the "whys" behind that rule, you come up with concepts of visible utility being preferable to abstract measurements, principles of certainty, relative permanence, and the like. But if in a particular instance the use of a monument does not further those aims, then it probably should be rejected.
With water boundaries the reasons behind the rules are complex, elusive and often arbitrary. Why, for instance, does a call for a stream in a metes and bounds description mean that the location of the stream controls over a series of meander courses following the stream? Usually, the courts say that the stream is a natural monument and leave it at that. However, the same court may apply the rule that a lateral shifting of the stream by accretion moves the boundary, but a movement by avulsive action leaves the boundary at the meanders. Obviously there is more at play here than the certainty of visible monuments being preferable to abstract measurements. The law may view a stream as having a relatively permanent existence, but it will never consider the stream's location to be permanent. Consequently it throws in a balancing between the importance of maintaining stream access for a riparian owner with the societal value of allowing people to adjust the use of their property to follow slowly moving natural boundaries but not rapidly moving ones. This leaves you with more questions, such as "How fast is an avulsion and when does it start?" I once read a court report where the judges blithely stated-in reference to a western river that had slowly shifted its banks until it was blocked by a log jam, whereupon it jumped out of its channel and formed a new one-that the boundaries along the river had moved until the "original" avulsion, when they became stationary. Of course a river that jumps its banks once will probably do it again and again (and had before), so I was left wondering what possible means a surveyor on the ground would have to determine which move was the "original" avulsion?