The back channel of Ash Island provides some really nice paddling close to Portland. Paddlers can launch from the Chehalem Paddle Launch in Dundee. Very few powerboats travel up the back channel because of submerged pilings at the south end confluence with the main channel.
If you're into fishing, there is some nice bass fishing in the summer and salmon fishing in the fall and spring. This is also a good spot to see great blue herons, green herons, belted kingfishers, bald eagles, and ospreys.
Chehalem Paddle Launch is open in the summer and rents canoes, kayaks, and SUPs. The launch is only 45 minutes from downtown Portland in the heart of wine country.
Ash Island is private property, so no landing is allowed. Willamette Riverkeepers is in negotiations with the landowner to purchase part of the island. Ash Island would be a nice place to set up camp if you're on a multi-day paddling trip.