【Pour】 ,  【stream】 ,  【gush】 ,  【sluice】  are comparable when they mean to send forth or cause to send forth copiously.

【Pour】 usually suggests an abundant emission of what is sent forth, but it sometimes implies a coming in a course or 【stream】 , usually a continuous 【stream】 (as from a mouth, a spout, an orifice, or a wound).

【Stream】 suggests a flow that is circumscribed (as by issuance through a course or from an opening), though it also may connote abundance or continuousness in that flow.

【Gush】 implies a sudden and copious emission of or as if of something released from confinement; it often connotes a coming in a jet or in spurts.

【Sluice】  implies the operation of something like a 【sluice】 for the regulation or control of the flow of water; therefore the verb  【sluice】 suggests a sending of water or liquid over a surface in an abundant 【stream】 .