References in classic literature ?
The other three had stuck fast among the rocks, so that it was impossible to move them; the men returned, therefore, in despair, and declared the river unnavigable.
When the one chair in the room was at its usual place before the table, the canal was unnavigable.
We are surrounded with stronger things than bars or bolts; on the north side, an unnavigable ocean, where ship never sailed, and boat never swam; every other way we have above a thousand miles to pass through the Czar's own dominion, and by ways utterly impassable, except by the roads made by the government, and through the towns garrisoned by his troops; in short, we could neither pass undiscovered by the road, nor subsist any other way, so that it is in vain to attempt it.
From horizon to horizon the great road to the sands lay between the hills in a dull glitter of empty curves, resembling an unnavigable river of mud.
The dynamism of the war in Syria, and the sheer number of divergent interests and warring factions operating in the country show that the war is not winding down, but rather becoming more entangled and politically unnavigable .
These unnavigable [sic] African rivers, have in a way also affected life in Africa by restricting the movements of the Africans, especially in prehistoric times.
Following its ill-fated maiden voyage, Manta-Manaus was removed from the triumphant discourses of the Correa administration, as if in silent acknowledgment of its deserted highways, vacant airports and unnavigable watercourses.
Without including a wider array of historical representations however, the ability for spectators to "embark on their own interpretation" is not only abbreviated, but is unnavigable.
Just as mobile phones dispensed with landlines, cargo drones can transcend geographical barriers such as mountains, lakes, and unnavigable rivers without the need for large-scale physical infrastructure.
Steamboats have plied the Columbia since the 1830s, bringing fur and goods downriver to the Pacific, but the strong current and unnavigable falls made it challenging.
In many situations an attempt to study an entire stream can be hindered by stream access, unnavigable sections of stream, inability to secure land owner permission, or simply the cost of spending extra time on the river.
At that time, the Great Lakes were isolated from the Atlantic, unreachable by boat not only because of their unnavigable shorelines but also because of the challenges of crossing waterfalls.