Dunn No. 1 is a privately owned earth dam located in Guernsey, Wyoming, along Spring Creek. Built in 1954 for irrigation purposes, this dam stands at a height of 27 feet and has a maximum storage capacity of 58 acre-feet. Despite its poor condition assessment in 2018, the hazard potential is considered low, with a moderate risk level.

The dam's structure consists of stone core types and a soil foundation, with a spillway width of 50 feet for uncontrolled water release. While the last inspection took place in July 2018, with an inspection frequency of 5 years, the emergency action plan (EAP) status and risk management measures remain unknown. The overall risk assessment for Dunn No. 1 is deemed moderate, highlighting the importance of ongoing monitoring and maintenance to ensure its integrity and safety.

Given its critical role in irrigation and water resource management, Dunn No. 1 serves as a vital infrastructure component in Converse County. With the dam's location within the Omaha District and under the regulatory oversight of the Wyoming State Engineer's Office, continued efforts are needed to address the dam's poor condition and implement necessary risk management strategies to safeguard against potential hazards and ensure long-term functionality.