Sitla - Sienna Hills is a privately owned dam located in Washington County, Utah, designed for flood risk reduction along the Grapevine Crossing Wash. The dam is regulated by the Utah Division of Water Rights and is subject to state jurisdiction, permitting, inspection, and enforcement. With a hydraulic height of 17.7 feet and a structural height of 26 feet, Sitla - Sienna Hills has a low hazard potential and is currently not rated for its condition assessment.

Although the dam's completion year, storage volume, and other specific details are not provided, it is known to have a normal storage capacity of 15.9 acre-feet and a maximum discharge of 847 cubic feet per second. The dam is primarily made of earth materials and spans a length of 330 feet. Despite its low hazard potential, the dam undergoes inspections every five years to ensure its structural integrity and compliance with safety guidelines. Overall, Sitla - Sienna Hills serves as a vital infrastructure for flood risk mitigation in the region.