The Lower Rock Watershed (HUC 07090005) covers approximately 1,222 square miles in northeastern Iowa and encompasses parts of Clayton, Dubuque, and Delaware counties. The primary hydrological features of the watershed include the Maquoketa River, the Turkey River, and their tributaries. The area experiences a continental climate with hot summers and cold winters, and it receives an average annual precipitation of around 35 inches. The watershed is also known for its heavy snowfall during the winter months. Surface water quality in the watershed is influenced by agricultural practices, and high levels of nutrients and sediment can be found in some waterways. The watershed contains several reservoirs, including Lake Delhi and Lake Maquoketa. Lake Delhi has experienced issues with sedimentation and water quality in recent years, leading to restoration efforts.