Impulse turbines (e.g., Pelton wheels) convert the kinetic energy of a high-velocity water jet and operate in air, making them suited to high-head, low-flow sites. Reaction turbines (Francis, Kaplan) are fully submerged and extract energy from both pressure and velocity, suited to lower-head, higher-flow installations. Both fall under this heading, but the distinction matters for engineering specifications, site suitability, and supplier selection.

Hydraulic turbines are industrial capital goods and do not require admissibility review by food, drug, or agricultural agencies. However, large hydropower projects on navigable US waterways typically require Federal Energy Regulatory Commission (FERC) licensing, which governs the project rather than the equipment import itself. Standard CBP entry procedures apply.