Based on the available information, the Grandad Road boat ramp in Clearwater County, Idaho is a concrete boat ramp. It is approximately 20 feet wide, providing ample space for boats to be launched or retrieved. This boat ramp services the Dworshak Reservoir, which is a large body of water located in Clearwater County.

The Dworshak Reservoir is known for its crystal-clear waters and scenic beauty, and it is a popular destination for boating, fishing, and other recreational activities. According to the latest information available, the reservoir permits a variety of watercraft, including motorboats, sailboats, canoes, and kayaks.

Overall, the Grandad Road boat ramp is an important access point for boaters and water enthusiasts looking to enjoy the natural beauty of the Dworshak Reservoir. Its concrete construction and ample width make it a convenient and safe option for launching and retrieving boats of all types and sizes.