There are quite a few options Terrill.
Fraser RiverIf you are after salmon, there will be several species returning into the Fraser River in August. These are chinook, sockeye and pink salmon. This year is the peak year for pink salmon return, the estimated return size is in the 6 million fish range. September is usually the month for pinks, but the odd fish do emerge in August as well, especially late August. There are many locations to target these fish, and when the trip gets closer I'm sure you'll find out about those spots on here. The opening seasons on the Fraser River can sometimes change in the last minute, so it is hard to give precise locations and times at this point. There are also various coarse fish species that you can target.
Capilano RiverThe Capilano River is located in North Vancouver, about 10 to 20 minutes from Downtown Vancouver. In August, the mouth of Capilano should be stacked with coho salmon, but they are not easy to catch. Spinning with various lures is the method.
Seymour RiverSeymour River is also located in North Vancouver, just beside the Second Narrows Bridge. Expect pink salmon to arrive at the river mouth. Openings have not been announced at this point.
Vancouver Island streamsSomeone else maybe able to provide more information on this. A trip to the island, not just for fishing, is recommended. Some of the river further north should be good for salmon.
Chilliwack RiverChilliwack River is located around 1.5 hours from Vancouver. In late August, you should be able to see some pink salmon in the river and also the odd chinook salmon.
Since you are coming all the way out here, I would also highly recommend to take a guiding trip out for a day, or half a day. You will have a good time. Sturgeon fishing will be excellent in the Fraser River, and you will also be able to do some salmon fishing after a few hours of sturgeon fishing. Randy at
Ultimate Sportfishing maybe able to cater your needs.