fluid dynamics - What is the shape of a stream of water coming out of pipe?

As shown in the photograph below, when water comes out of a pipe (located on the surface of the earth) it travels downwards in an arc.

What is the shape and size of this arc as a function of D, the inner diameter of the pipe and, P, the pressure of the water? I suppose the shape is either a parabola, or maybe a catenary. Assume the pipe is horizontal and the water is exiting the pipe perpendicular to gravity.

(Although a thrown object will have a parabolic trajectory, I don't think I can assume that a stream of water will necessarily be parabolic because the water stream has viscosity.)