Why do the colorado river, rio grande, nile river, and yellow river now slow to a trickle or run dry before reaching their deltas?

There are several reasons due to which the colorado river, rio grande, nile river, and yellow river now slow to a trickle or run dry before reaching their deltas. The first and the most important reason is the uncontrolled draining of the surface waters for drinking and other purposes. The altering of the plant communities and destroying marine life has added to this problem. Deposition of unwanted materials in the river is also another reason.