The Castle Rock watershed (HUC 07070003) covers an area of approximately 413 square miles in Colorado. The hydrology of the area is dominated by the South Platte River, which flows through the middle of the watershed. The watershed also contains several smaller streams and creeks. Snowpack is an important component of the Castle Rock watershed's hydrology, with winter snowfall contributing to the majority of the area's surface water supply. The watershed is also home to several reservoirs, which store water for municipal and agricultural use. Interesting climatic facts include the area's semi-arid climate, with hot summers and cold winters. The Castle Rock watershed has experienced a trend of decreasing snowpack in recent years, which has led to concerns about water availability for the area's growing population. In addition, the watershed is susceptible to frequent droughts, which can impact both surface water and groundwater resources.