Everybody now regards it as a perfectly legitimate use of the government to create rights of way in the public water. Modern writers treat this as saying as though water is owned by the state and held in a public trust. Now this is completely wrong as a matter of Roman law. Because this is a natural law system. If you're in a natural law society there is no such thing as the citizens because it turns out there is no such thing as the state. It's an absolutely open access regime to everybody in the face of the world. It's interesting when you start looking at Gaius and Justinian on this. All they tend to worry about is the basic intuition. Clearly correct, but insufficient, that no one person can damn up a river. If it turns out that there aren't a whole lot of people trying to use the river in one way or another you don't need to have any traffic rules. But the moment it turns out that transportation along a river becomes heavy, you will start to see a very powerful effort to separate people so they don't go crashing into one another. You need to have somebody to do this for the entire river and by default, it's always the state that does this. We call this public trust. Why do we use the word trust? Because the government is not treating this as though it's an outright owner of the particular property in question. It's a trustee and it's mission in this case is to maximize the value of the river for all of the people who use it. The more systematic elaboration of this tends to take place in English times. Why didn't the Romans tend to do it? Well generally speaking if you have limited private users and sparse populations, no matter how much anybody takes out of the river, if they're not diverting the whole thing there's going to be enough for everybody else to do more or less what they want. So the basic rule in allocation has always been, if it's a low intensity use, we don't try to put into case a complicated property system. We just let everybody take as much as they want. But the moment that the uses become much more systematic, the correlative duties to other individuals become much more important and we have to figure out this system. Which was done with an amazing sophistication, the simple riparian systems by the English water law as it matured, certainly by the middle of the 19th century, and a good deal earlier than that. It's a perfectly sensible legitimate use of property rights, but it's not as though this is part of the Roman system. They never got this far. It becomes part of any new system which has to deal with intensity abuses.