Boise River Location: about 7 miles east of Boise on Idaho Highway 21
The put-in is Discovery Park which is just downstream from Lucky Peak Dam. There is an entry fee since it's part of Lucky Peak State Park though entry is free if you have an Idaho State Parks Passport ($10 annually. See the Idaho State Parks and Recreation site).
This paddle boarding location provides the opportunity to just paddle around the put-in or cover some distance by heading down the Diversion Dam backwater.
You can paddle in the area of the park or head down toward Diversion Dam. The dam was built in 1906-1908 and diverts part of the Boise River into the New York Canal. There is a slight current heading toward the dam but it's easy to paddle against. Headwinds are usually a bigger problem than the current. When the river is high in the spring, there is considerable current and waves at Discovery Park. The put-in is in an eddy so it's calm there but things pick up as you move out into the current!
The water comes out of the bottom of Lucky Peak reservoir so it's pretty cold all summer.