Knick points
A knick point = a sudden break or irregualrity in the gradient along the long profile of a river.
Some knick points = shaply defined- waterfalls, whereas others are barely noticeable.
A number of factors can cause such features to occur- commonly attributed to rejuvenation.
When a river is rejuvenated= adjustment to the new base level starts at the sea + gradually works its way up the river's
course= the river gains renewed cutting power (in the form of vertical erosion)= encourages it to adjust its long profie.
The knick point is where the old long profile joins the new.
The knick point - recedes upstream at a rate which is dependent on the resistance of the rocks- may linger at a relatively hard outcrop.
Difficult to determine whether a waterfall occurs due to variability in rock type or rejuvenation.
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