Boya Lake Provincial Park Campground Photo - looking at Boya Lake, BC. from Boya Lake Provincial Park Campground. The lake is noted for its colour and clarity. The bottom is composed of marl, a mixture of silt and shell fragments. The crystal clear waters and aqua-marine lake colour are a result of the light reflecting from the marl bottom. The Stewart-Cassiar Highway The Stewart-Cassiar Highway runs from the junction of Highway #16 (The Yellowhead Route) north to the Yukon border and connects with The Alaska Highway.This highway offers some of the most awe-inspiring scenery, with wild rivers, deep canyons and wildlife that you will encouter along the way.