We saw that the produce of the agriculture of Babylon, the fruit of the field, depended on the irrigation, the system of canals, and the regulation of the overflow of the Euphrates. Nebuchadnezzar must have commenced his work by putting in order the dams of the Euphrates, which it was no easy task to keep up, by providing with water-courses or cleaning out the canals which had become dry or blocked up.[683] The great canals of the old kings were still in existence, the canal of Hammurabi, the Narsares, the Pallakopas, and the connecting canals between the Euphrates and Tigris above Babylon.[684] Nebuchadnezzar must have taken measures for their restoration. He increased the number of the connections between the Euphrates and the Tigris, and made them more useful by cutting a new canal from the Euphrates to the Tigris, of sufficient dimensions to carry the largest vessels. This was the Nahr Malka, _i.e._ the king's trench. Herodotus calls it the largest of the Babylonian canals. According to Xenophon's statement there were four canals connecting the Euphrates and the Tigris, one hundred feet in breadth, and deep enough to carry even corn ships. They were bridged over, and about four miles from each other. From these were derived the canals of irrigation, first the large, then the small, and lastly runnels like those in Greece for watering the fields of millet. The larger canals of irrigation were so deep that the Greeks with Clearchus could not cross them without bridges; and for the construction of these the palms which shadowed the banks of the canals were felled. Clearchus and Xenophon crossed the two northernmost of the connecting canals in order to come from the Median wall to Sittace on the Tigris. The first they crossed by the permanent bridge, the second by a bridge of boats supported by seven merchantmen. The lining of these canals was constructed of bricks, united with asphalt-mortar. There still exist four canals connecting the Tigris and the Euphrates. The Saklawiye is followed by the Nahr Sersar; further to the south is the Nahr Malka, which leaves the eastern bank of the Euphrates below Feludsha, in order to reach the Tigris at the point marked by the ruins of Seleucia--this is the great canal constructed by Nebuchadnezzar: lastly, immediately above Babylon, is the Nahr Kutha, named after the city of Kutha. Thus Nebuchadnezzar completed the old canal system of Babylon; he facilitated the communication between the two rivers in the upper part of the land, and increased the irrigation. He also gave attention to the lower land: between the Narsares and the Pallakopas, which carry away the overflow of the water of the Euphrates, below Babylon, he made trenches in order to drain the marsh, and he caused dams to be erected on the sea-coast in order to keep out the inundations of the sea.[685]