I am hoping for some help finding quality bass in August on the lower end of the river, within 15 miles or so of the dam due to fuel restraints on my boat. I have only fished it once before and caught plenty of smallmouth, but nothing over a pound. Any tips on where to find some bigger smallies would be great. And if there's any chance of finding largemouth that close to the dam that would be amazing but I've heard they are farther up the river than I can reach. Thanks in advance.

Lake Roosevelt isn't exactly a bass fishing mecca... walleye, sturgeon and trout are the kings of the current there. However, if you fish farther north say from Lincoln to Hunters you will find a seven population of sizable smallies 3-4lbs. Good luck with the largemouth, far and few between. Since you have range limitations with your boat, i suggest launching from, Lincoln, seven bays or fort spokane, that way you can fish both the Columbia and Spokane arms of the lake.