1Ulpianus, On the Edict, Book LXVIII. The Prætor says: “Nothing shall be thrown into a public river or deposited on its banks, by means of which the landing of merchandise, traffic, or the movement of shipping may be interfered with.” 1A river is distinguished from a small stream by its superior size, or by the opinion of the people who live in the neighborhood. 2Some rivers have a continuous flow, and others are torrential. Those which have a continuous flow run always; those which are torrential only flow during the winter. If, however, a river, which at other times continues to flow, should dry up in the summer, it will not, on this account, be removed from the former class. 3Some rivers are public, and some are not. Cassius defines a public river to be one which flows uninterruptedly. This opinion of Cassius, which is approved by Celsus, seems to be plausible. 4This interdict has reference to public rivers, but it does not apply to one which is private, because a private river does not differ from other places which belong to individuals. 5A bank is properly defined to be what contains a river when it pursues its natural course, for it does not change its banks on account of rain, the tide, or for any other reason. No one says that the Nile, which covers Egypt with its overflow, changes or enlarges its banks; for when it returns to its ordinary dimensions, the sides of its channel should be repaired. If, however, a river should naturally increase in size in such a way as to acquire a permanent enlargement, either through the addition of the water of another stream, or for some other cause, it undoubtedly must be held that it has changed its banks, just as if, having changed its bed, it begins to flow elsewhere. 6If an island is formed in a public river, and anything is built upon it, it will not be considered to have been constructed in a public place, for the island becomes the property of the first occupant if the neighboring fields have regular boundaries; or belongs to him to whose bank it is contiguous; or if formed in the middle of the channel, it will belong to those who own land on both banks of the stream. 7In like manner, if a river leaves its bed and begins to flow elsewhere, anything which was built in the old bed will not come under the terms of this interdict, for what belongs to the neighbors on both sides is not constructed in a public stream; or, if the land has boundaries, the bed of the river will belong to the first occupant, and it certainly ceases to be public property. Moreover, although the new bed which the river has made for itself was previously private property, it at once becomes public; because it is impossible for the bed of a public stream not to be public. 8A canal, made by human hands, through which a public river flows is, nevertheless, public property to such an extent that if anything is built there, it is considered to have been built in a public stream. 9It is otherwise if a river overflows the land of another, and does not make a new bed for itself; for then what the water covered does not become public property. 10Again, if a river surrounds land, it must be noted that the land still remains the property of the original owner. Therefore, if anything is built in it, it is not built in a public stream. Whatever is done on private land does not come within the scope of this interdict, any more than what is done in a private stream; for anything which is done in a private stream is just the same as if it was done in any other place belonging to a private individual. 11We understand anything to have been built in a public stream where this was done in the water itself; for if anything is built outside of the water, it is not considered to have been done in the stream, so that any structure erected upon the bank is not held to have been built in the stream. 12The Prætor does not absolutely prohibit any work being done in a public river, or on the bank of the same, but only whatever may interfere with the landing of goods, or navigation. Therefore, this interdict only applies to public rivers which are navigable, and not to any others. Labeo, however, says that even if anything is done to a river that is not navigable, which may cause it to dry up, or which obstructs the course of the water, it will not be unjust to grant an available interdict to prevent any violence from being employed against removing or demolishing a structure which has been built in the bed of the stream, or on its bank, that interferes with the passage or current of the river, and to compel everything to be re-established in good condition, in accordance with the judgment of a reliable citizen. 13The word statio, a landing-place for ships, is derived from the verb statuo. By it, therefore, the place is indicated where ships can remain in safety. 14The Prætor says, “or the movement of shipping may be interfered with.” This is used instead of the word navigation, and, indeed, we are accustomed to employ the terms shipping and navigation, instead of the vessel itself. Hence, by the term “shipping” may also be understood the course of the vessel. Boats are also included in this term, for their use is frequently necessary. If the approach for pedestrians is obstructed, the movement of shipping is also interfered with. 15The anchorage and the course of navigation are also considered to be interfered with where the use of the same is interrupted, or rendered more difficult, or diminished, or made less frequent, or entirely destroyed. Hence, if the water is drawn away, and the river, having become smaller, is rendered less navigable; or if its width is increased, or the water being more widely distributed becomes shallower; or if, on the other hand, the stream is rendered more narrow, and runs very rapidly; or if anything is done to inconvenience navigation, make it more difficult, or entirely prevent it; there will be cause for the interdict. 16Labeo says that an exception on the ground that the work was only performed for the purpose of preserving the bank should not be granted to him who is sued under the interdict; but that it should be on the ground that nothing has been done except what was authorized by law. 17Where anything has been built in the sea, Labeo says that the following interdict will lie. “Nothing shall be constructed in the sea, or on the shore of the same, by which a harbor, anchorage, or the course of navigation may be obstructed.” 18He also thinks that the same rule will apply to any public stream which is not navigable. 19The Prætor further says, “If you have placed anything in a public river or done any work therein, or on the bank thereof, by which the anchorage of vessels or the course of navigation has been, or may be interfered with, you shall restore everything to its former condition.” 20The interdict above mentioned is prohibitory; the one which has reference to the same case is restitutory. 21He who has done any work, or placed anything in a river or upon its bank which may obstruct navigation, is obliged to restore everything to its former condition, if what he has done may interfere with the anchorage of vessels or their movements. 22The following words, “has done or placed,” indicate that he who built or deposited the obstruction is not liable, but that he who has possession of it after this has been done is liable. Finally, Labeo says that if your agent has diverted the course of the stream, you will be liable under this interdict, if you use the water.

2Pomponius, On Sabinus, Book XXXIV. There is nothing to prevent anyone from taking water from a public stream unless this is forbidden by the Emperor or the Senate; provided the water is intended for the use of the public. If the stream is either navigable, or another is rendered navigable by it, this is not permitted to be done.

3Paulus, On Sabinus, Book XVI. Public rivers which have a regular course, together with their banks, are public property. 1The banks of a river are considered to be those that confine it when the water is at its highest point. 2The places along the banks of a stream are not all public, as they are accessory to the banks, beginning at the point where the latter begins to incline from the level ground to the water.

4Scævola, Opinions, Book V. Inquiry has been made whether he who owns houses on both sides of a public stream has a right to build a bridge which will be his private property. The answer was that he cannot do so.