Sluice Gates, Slide Gate – These devices, consisting of operable gates with stems, are used to regulate water level within the impounded water body – a pond, lake or reservoir. They are often constructed of cast iron, in the case of sluice gates, or aluminum or stainless steel in the case of slide gates. Depending upon the size of the impoundment, the contributing watershed and the desirable level of water to be attained by opening the gates, they will vary in both size (amount of flow) and strength (depending on depth to a low level outlet).
Stop Log Structures – Often found with both old and new dams, stop logs are timbers or heavy boards set in channel type slides or guides to control water levels. Older dams used stop logs to control water level in place of sluice gates, while newer structures combine them within an intake or outlet structure to maintain water level along with a gate, thereby allowing the gate to be serviced and removed without having to lower the water level in the impoundment.