The velocity that water exits the bottom of a reservoir where the exit point area is extremely small relative to the opening(top) point area is
V1=SQROOT(2g(h2-h1)) where V2 is approximately 0.
If the velocity of V2 (the top) with both top and bottom under atmospheric pressure is taken into consideration then V1A1=V2A2 is substituted into
Bernoulli's equation to give V1 = Sqroot(2g(h2-h1)/1-(A1/A2)^2).

This says that as the area of A1(bottom) approaches the area of A2(top) the velocity at A1 approaches infinity. Is that right??
To increase the velocity without increasing A1 or changing the volume then the height of the reservoir should be increased. This could be done with a pipe attached to A1(bottom)??