1You fear, sir, with the greatest foresight, that the lake, if joined to the river and so to the sea, may drain away; 1but I, on the spot, think I have found a way to meet this danger. 2For the lake can be brought by a canal right up to the river and yet not let out into the river, but, by leaving a sort of bank, be both held in and kept apart. 2In this way we shall bring it about that the lake is not robbed of its water by being mixed with the river, and yet it will be just as if it were mixed. 2For it will be easy to transfer loads brought along the canal across that very narrow strip of land which will lie between, into the river.
3This will be done if necessity compels, and, I hope, it will not compel. 3For the lake itself is quite deep, and at present it lets a river out on the opposite side; if this is dammed there and turned where we wish, it will pour in as much water as it now carries, without any loss to the lake. 3Besides, streams cross the stretch through which the canal is to be dug; 3and if these are carefully gathered together, they will increase what the lake supplies. 4Again, if it should be decided to carry the canal further and, by cutting it deeper, to bring it level with the sea and let it out not into the river but into the sea itself, the back-pressure of the sea will keep in and hold back whatever comes from the lake.
4Even if the nature of the place provided us with none of these things, it would still be easy to regulate the flow of the water with sluices. 5But these and other things will be investigated and explored far more shrewdly by a surveyor, whom you certainly ought to send, sir, as you promise. 5For the undertaking is worthy both of your greatness and of your care. 5Meanwhile, on your authority, I have written to Calpurnius Macer, a most distinguished man, to send the most suitable surveyor possible.