Lost black rugged backpack with several pockets and hydration reservoir near the picnic area by the Brule River in Northern Wisconsin.

I lost my favorite black backpack near the picnic area by the Brule River in Northern WI. It has several pockets, is kind of rugged, and contains a hydration reservoir. I last remember having it while I was unpacking my lunch. I’ve had that backpack for years, and it carries some sentimental value to me.