Lum Hollow Subwatershed M-13210 is a small earth dam located in Woodbury County, Iowa, near the Missouri River. Built in 1959 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock watering, and small fish pond management. With a dam height of 26 feet and a storage capacity of 68 acre-feet, this structure plays a significant role in flood risk reduction within the Lum Hollow Creek watershed.

Despite its relatively low hazard potential, Lum Hollow Subwatershed M-13210 is regulated by the Iowa DNR and undergoes regular state inspections to ensure its structural integrity and functionality. The dam has a drainage area of 3.35 square miles and a surface area of 2.5 acres, making it an essential component of the local water resource management system. While the dam's condition assessment is currently listed as "not rated," its risk assessment indicates a moderate level of risk, highlighting the importance of ongoing monitoring and maintenance efforts.

Overall, Lum Hollow Subwatershed M-13210 serves as a vital water management structure in the region, providing essential services for both agricultural and environmental purposes. With its connection to the Lum Hollow Creek and proximity to the Missouri River, this dam plays a crucial role in mitigating flood risks and supporting the overall health of the local ecosystem. As climate change continues to impact water resources, structures like Lum Hollow Subwatershed M-13210 will play an increasingly important role in sustainable water management practices.