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From its sources until it leaves Brailé lake the river lies in the mountains where its grade is too steep for navigation. Beyond this point it pursues a northeasterly course, cutting a deep valley through the Alberta plateau and receiving in succession the waters of Baptiste river from the west, McLeod and Pembina rivers from the south, and Lesser Slave river from the northwest. The mouth of McLeod river, elevation 2,262 feet, is considered to be the upper limit of possible steamboat navigation, which then extends for a distance of 325 miles down to the head of Grand rapids. This portion of the river has an average fall of about 3 feet to the mile and is broken by a number of minor rapids, especially above the town of Athabaska, but none of them is sufficiently rough to obstruct the passage of steamboats during medium and high stages of water. Rapids also oecur on Lesser Slave river, but in these the channel has been improved and deepened so as‘to allow steamboats to ascend the river to Lesser Slave lake. Lesser Slave river is one of the largest tributaries of Athabaska river and at ordinary high-water stage has a discharge of about 2,300. cubic feet per second.

From Athabaska the river has a more northerly trend and although the stream runs with a strong current it is not broken by any rapids as far as Pelican rapids, ‘a distance of 120 miles. Pelican rapids, however, present no diffi- culties to navigation except in low water when the channel is obstructed by some boulders. Broken water also occurs at two other points below Pelican rapids, but boats which are able to navigate Pelican rapids would have no difficulty in . descending the additional 45 miles to Grand rapids which is the lower limit of steamboat navigation on this portion of the river. The river in this portion is from 250 to 400 yards wide and its valley varies from 300 to 400 feet in depth.

At Grand rapids the character of the river changes, its grade becomes greatly increased, and for the next 85 miles or as far as the mouth of Clearwater river it is broken by swift and dangerous rapids every few miles. The average grade of this portion is nearly 5 feet to the mile and the valley is 500 to 600 feet deep and frequently gorge-like. This portion is navigable only for scows or canoes and that with difficulty.

At Grand rapids (Plate III B) the river falls 50 or 60 feet in about half a mile and the main channel is not navigable by craft of any kind. A small island about a quarter of a mile long lies opposite the worst part of the rapids and over this goods are carried, and the scows are run down empty to the east of the island through a channel that has been blasted out among the boulders.

Rough water which requires some care in navigation extends for 2 or 3 miles below Grand rapids, but beyond this the river runs smoothly for over 20 miles to: what are known as Burnt rapids. Here the stream widens to 400 yards and becomes shallow and occupied by scattered boulders. The canoe and boat channel follows the left side of the river and by keeping not more than 20 or 30 yards from the shore there should be no danger to experienced boatmen in the descent.

About 16 miles of smooth water follows Burnt rapids, below which the river falls in quick succession over Boiler, Drowned, Middle, and Long rapids, all of which occur within a stretch of 7 miles. They are all similar in character to Burnt rapids and owe their existence to a steepening of grade and an accumula- tion of boulders in the channel. In Boiler rapid the boat and canoe channels are’ on the left side and are so crooked that much care must be exercised to navigate them with safety. In Drowned rapid the channel is also on the left side and is somewhat rough. About a mile below is Middle rapid which presents no great