The Green River in Utah is a popular destination for whitewater enthusiasts due to its challenging rapids and beautiful scenery. The ideal streamflow range for rafting on the Green River varies depending on the segment being run. For example, the ideal flow for the Labyrinth Canyon section is between 2,000-8,000 cubic feet per second (cfs), while the ideal flow for the Cataract Canyon section is between 8,000-25,000 cfs.

The Green River is rated as a Class II-IV river, meaning it has a mix of rapids ranging from moderate to difficult. The Labyrinth Canyon section is a Class II river, while the Cataract Canyon section is a Class III-IV river.

The Green River is divided into two main sections: the Labyrinth Canyon section, which is 68 miles long, and the Cataract Canyon section, which is 46 miles long. The Labyrinth Canyon section is known for its calm stretches of water and scenic red rock formations, while the Cataract Canyon section features challenging rapids such as "Big Drop" and "Powell's Pocket."

There are several regulations in place for the Green River, including a permit system for overnight trips and restrictions on the use of motorized watercraft. Additionally, visitors must be aware of the Leave No Trace principles and follow all rules and regulations set forth by the National Park Service and Bureau of Land Management.

Overall, the Green River in Utah offers a thrilling whitewater experience for those who are up for the challenge. However, visitors must take caution and follow all regulations to ensure the safety of themselves and the river.