Lucas. By the time they reach the river channel they increase to more than thirty feet, and tidal currents become violent. Observations have been made which show a vertical rise of water approximating ten feet in five minutes. As early as 1873 ^^^ Sentinel carried an interesting account of this phenomenon.
The spring tides of the Gulf run to a height of thirty feet. This expanded volume of the waters of the Gulf is coincident with the spring floods of the Colorado River. When the two come together, they form what is called a "bore." The impetuous waters of the river . . . rise to a height which of their own impetus overflow the banks of that stream. At this moment the extreme spring tides of the Gulf come roaring up the Colorado. In immense volume they encounter the swell of river waters, and the heavier specific gravity of the salt water sends the stream of the Colorado back on itself for miles, with a mighty roar, to which that of the Niagara is tame ... It is a scene of majesty which . . . can never be forgotten.^^o
The experience of Lieutenant Robert William Hale Hardy with the "bore" is an interesting one. On entering the mouth of the river in 1826, his ship, the Bruja, was struck by the bore with so terrific a shock that the rudder was snapped. She was thrown ashore, where she remained high and dry for eight days until flood tide again reached and refloated her.^^^
A second problem arose from the excessive load of silt deposited at the river delta. To overcome the hazard of striking these hidden bars, it was customary to wait for flood tide and ride in over the danger area. Once inside the river channel the problem became one of avoiding the sand bars caused by the constantly changing course of the river. It was impossible to chart a river course which would be reliable for more than several hours, and consequently the most experienced river pilots were required to "tie up" along the bank during the night to await daybreak before proceeding. One of the characteristic features of any river steamer was the Indian stationed at the bow, stripped to the breeze, with a long, cottonwood, sounding pole in his hand. At frequent intervals he plunged the pole into the water to take soundings, which he called back to the captain or which he communicated to him by simply raising the pole so that the captain could see the water mark and judge the depth for himself. As deck hands the Indians were paid fifty cents a day. "Not being able to count money, each native kept a tally of the number of days he worked by tying knots in a string he wore around his neck. Each knot recorded a day's work. An Indian demanded as many half-dollars as he had knots on his string."^^^
The "desert pilot" devised his own methods of combatting the problems of navigation. If the vessel ran on a bar, he might resort to several methods to get her off. The boat might be rocked off, if the pilot were skillful, or she might be pried loose. Often patience was the only solution to the problem, for if the boat were allowed to remain long enough, the changing current would eventually wash her free. Captain Mellon is said to have remained in such a position for fifty-two days.^^^ If the vessel was in very shallow water.
