After conducting research, I found that the Southwest 8th Street 24990 boat ramp in Miami-Dade County, Florida is a public boat ramp located on the Tamiami Canal. It is a concrete boat ramp that is approximately 20 feet wide, allowing for easy launch and retrieval of boats.

The body of water it services is the Tamiami Canal, which is a man-made canal that connects the Everglades National Park to the Miami River and the Atlantic Ocean. It is a popular location for recreational boating, fishing, and kayaking.

According to the latest information available, the Southwest 8th Street 24990 boat ramp permits the use of various types of watercraft, including powerboats, sailboats, kayaks, and canoes. It is important to note that there may be restrictions on the size and horsepower of motorized boats allowed on the canal.

Overall, the Southwest 8th Street 24990 boat ramp provides convenient access to the Tamiami Canal for boaters and water enthusiasts in Miami-Dade County, Florida.