Water Control gates and valves are often used in water and wastewater filtration plants. Larger specialty gates are often used in water conveyance. Level Control Gates, Radial Gates, Canal Gates, Sluice Gates, and Slide Gates to be used in water transportation. Canal Gates are often used in water distribution through canals and pipes are used in water conveyance. Drainage gates for holding excess flood water. The level control and tide control gates can help prevent flooding.