Sinclair Dam in Lineville, Iowa, is a privately owned structure designed by the USDA NRCS in 1977 for fire protection, stock, or small fish pond purposes. The earth dam, standing at a height of 28 feet and a length of 410 feet, has a storage capacity of 60 acre-feet and serves as a vital water resource for the surrounding area. Located on TR-Caleb Creek in Wayne County, Sinclair Dam is regulated by the Iowa Department of Natural Resources and is subject to state permitting, inspection, and enforcement.

Despite its low hazard potential and moderate risk assessment, Sinclair Dam has not been rated for its condition. The dam has a surface area of 7.6 acres and drains a 0.34 square mile watershed. While the spillway type is uncontrolled, the dam has a maximum storage capacity of 60 acre-feet and a normal storage level of 21 acre-feet. The dam's location, along with its design and purpose, underscores its importance in providing essential water resources for fire protection and agricultural activities in the region.

As a key component of the water infrastructure in the area, Sinclair Dam plays a critical role in ensuring water availability for various uses while minimizing potential risks. The dam's importance is further emphasized by its association with the Natural Resources Conservation Service and its compliance with state regulations and jurisdiction. For water resource and climate enthusiasts, Sinclair Dam serves as a noteworthy structure that highlights the intersection of water management, agricultural needs, and environmental stewardship in the state of Iowa.