Usually, there are only small portions of a river that flows against the slope of the land , or gravity. I work at a park on the White River in Hamilton County IN. We are in a huge bend in the river and the White River flows northward at this point, against the slope for about a 1/4 of a mile. This happens on the St. Joseph River in northern Indiana and a co-worker tells me the Cuyahoga in Ohio also has this phenomena. I reckon it is an uncommon, but not rare, situation.
Gravity
A river naturally flows from high to low elevations by gravity.
no
It was going against the flow of the river. The Nile flows north.
A river naturally flows from high to low elevations by gravity.
Gravity. The river bed slopes, and water flows from the higher place to the lower.
The river usually flows downwards due to gravity, following the path of least resistance towards lower elevations or towards the ocean.
Gravity makes the water in a river flow. The location from which the water flows is slightly higher in elevation than the locations to which it is flowing, i.e. the water is flowing downhill. The water is also losing potential energy as it flows, which equals the force that keeps it in motion.
It flows slower because when a river goes down it flows faster because gravity is helping it and when its on a flat area it doesn't move as fast because gravity isn't help pull the water down therefore making it slower.
Gravity makes higher and lower water flow which makes it deaper or shallower.
The general direction a river flows is down. The water responds to the pull of gravity, and it is pulled down - whichever way that happens to be (north, south, east, west, or whatever). Water flows downhill. Simple and easy. Nothing tricky about it.
As with all rivers the Nile cannot defy gravity and therefore flows 'downhill'.