The Whitewater River Run Segment B in Virginia is a 3.5-mile stretch that runs from the Northern Boundary, Hidden Valley Tract to the Southern Boundary of Hidden Valley Tract. The ideal streamflow range for this segment is between 500-1000 cfs. This section is rated as a class III-IV, meaning that it has moderate to high rapids with larger waves or drops, and requires significant skill and experience to navigate.

The river rapids in this segment include The Slot, which is a narrow chute with a drop that requires precise navigation, and Pinball, which has several large rocks that create obstacles for rafters and kayakers. This section also has several other class III and IV rapids that provide a thrilling whitewater experience.

Specific regulations to the area include a permit requirement to access the river, and a restriction on the number of people allowed per group. Additionally, all participants must wear a personal flotation device (PFD) and helmets are recommended. It is also important to note that this section of the river can be dangerous during high water levels and should only be attempted by experienced and properly equipped paddlers.

Overall, the Whitewater River Run Segment B is a challenging and exciting whitewater experience that requires skill, experience, and proper equipment. It is important to adhere to all regulations and safety guidelines to ensure a safe and enjoyable trip.