336 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
With the next rise in the river, however, the fears of the engineers 
were fulfilled. Following a capricious mood, the river concluded to 
go down the easy channel toward the Alamo and sent from day to 
day an ever-increasing flood, rapidly eroding the channel. This con- 
tinued until, in the spring of 1905, the entire river was passing by 
an abrupt turn to the westward down the Alamo channel, spread- 
ing out over the low ground, and ultimately converging toward Vol- 
cano Lake, or northerly into the New River and the Salton Sea. 
The old channel of the river, where it formed a part of the inter- 
national boundary and at points below, soon became completely dry 
and rapidly assumed the ordinary appearance of the alluvial desert. 
Willows quickly sprung up, and in the course of a few years, under 
the influence of the winds and rapidly growing vegetation, the chan- 
nel would have disappeared as a conspicuous feature. 
CUTTING OF NEW CHANNEL. 
The water entering through heading No. 3 filled to overflow- 
ing the natural bed of the Alamo. It swept out across the desert, 
diverging and converging, forming many streams, and in places 
covering the nearly level ground with a sheet of water which ex- 
tended as far as the eye could reach. All of the soil of this 
country had been deposited by the wind or by the river in its previous 
excursions, and hence consisted of extremely soft layers of sandy 
silt or fine mud. As the water progressed toward the depression 
filled by the Salton Sea it tended to gather into narrow streams. 
Gaining velocity with increase of slope, these began quickly to estab- 
lish for themselves definite beds by scouring out the soft material. At 
first slight falls or riffles were formed. Later these progressed back- 
ward, deepening as the water scoured out the channel which had 
formed in the soft earth. : 
Converging from broad sheets, water poured over the edges of the 
rapidly eroding silt and in some places, as shown in Pl. IV, formed 
waterfalls comparable almost to Niagara in their size and in their 
apparent height, when compared with the broad level plain. These 
falls in some places in the softer beds progressed backward at the 
rate of about a mile in three days. Occasionally the water would 
strike a harder layer and the rate of progress would be slower. As 
these falls retreated backward, forming a definite channel for the 
waters, the broad expanse was suddenly drawn down, and what was 
to the eye a wide lake became in a few hours a mud flat, traversed 
by a deep, narrow gorge, a thousand feet or less in width, filled 
by a foaming torrent. 
Sometimes the water coming from Colorado River overflowed the 
fields of the farmers and the grain or alfalfa was overtopped by the 
