Assertion: river's current | /r/CapableOf | present great impediment
Facets:
value: for with a large fall
type: CAUSE
value: to up-stream navigation
type: TRANSITIVE-OBJECT
Source sentences:
text: Engineering works to increase the navigability of rivers can only be advantageously undertaken in large rivers with a moderate fall and a fair discharge at their lowest stage, for with a large fall the current presents a great impediment to up-stream navigation, and there are generally great variations in water level, and when the discharge becomes very small in the dry season.