Phillips Subwatershed Site 5740, located in Monona, Iowa, is a locally-owned earth dam completed in 1956 by the USDA NRCS. This dam serves multiple purposes including fire protection, stock watering, and small fish pond maintenance. Situated on the TR-Maple River, it has a low hazard potential and is not currently rated for condition assessment. With a maximum storage capacity of 90 acre-feet and a normal storage capacity of 71 acre-feet, this dam covers a surface area of 4 acres and drains a 0.26 square mile watershed area.

Despite being primarily used for fire protection and flood risk reduction, the Phillips Subwatershed Site 5740 is regulated and permitted by the Iowa DNR, ensuring that it meets state inspection and enforcement requirements. The dam has an uncontrolled spillway and stands at a height of 50 feet, providing essential water resource management in the region. With a moderate risk assessment rating of 3, this dam plays a crucial role in mitigating potential flooding and safeguarding the local ecosystem. As a key component of water resource infrastructure in the area, its management and maintenance remain integral to sustaining the region's environmental and agricultural landscapes.