The Lower Colorado Marble Canyon Watershed (HUC 15010001) covers an area of approximately 4,338 square miles in northern Arizona. The hydrology of the watershed is primarily driven by the Colorado River, which flows through the area and provides surface water for the region. The watershed is also home to several reservoirs, including Lake Powell and Lake Mead, which provide water for agricultural, industrial, and municipal uses. The region experiences a semi-arid climate, with hot summers and cold winters. Snowpack in the watershed varies from year to year, with some years seeing significant snowfall while others see very little. In recent years, the region has experienced a trend of decreasing snowpack, which has led to concerns about water availability in the future. Interesting climatic facts about the Lower Colorado Marble Canyon Watershed include the fact that it is one of the driest regions in the United States, with an average annual precipitation of less than 10 inches. The region is also home to several unique plant and animal species, including the endangered Mexican spotted owl.