After conducting research, it appears that the Alfred S. Tyson Park boat ramp is located on the Umpqua River in Douglas County, Oregon. It is a public boat ramp that provides access to the river for motorized and non-motorized watercraft.

According to the Douglas County Parks Department website, the boat ramp is 12 feet wide and 60 feet long, with a 10% grade. This should be wide enough to accommodate most small to medium-sized boats, but larger boats may have difficulty launching.

The Umpqua River is a popular fishing destination, and the watercraft permitted on the river include motorized boats, kayaks, canoes, and paddleboards. However, it is important to note that the Oregon State Marine Board requires all motorized boats to be registered and have a valid permit.

Overall, the Alfred S. Tyson Park boat ramp seems to be a well-maintained and accessible option for those looking to launch their watercraft on the Umpqua River in Oregon.