The Purgatoire Watershed (HUC 11020010) covers an area of approximately 2,504 square miles in southeastern Colorado and northeastern New Mexico. The hydrology of the watershed is dominated by the Purgatoire River, which is a tributary of the Arkansas River. The region experiences a semi-arid climate with low precipitation levels and high evapotranspiration rates, leading to limited surface water resources. Snowpack in the region is generally low and melts quickly due to high temperatures and intense sunlight. Surface water in the watershed is primarily used for irrigation, and the reservoirs in the region are used for water storage, flood control, and recreation. The watershed also contains several important fish and wildlife species, including the Arkansas darter and the Arkansas River shiner. In recent years, the Purgatoire Watershed has experienced increased temperatures and decreased precipitation, which has led to drought conditions and reduced water availability. These trends are expected to continue in the future, posing challenges for water management and conservation efforts in the region.