||The objective was to determine whether temperature, velocity, dissolved oxygen, or pH operate singly, synergistically, or additionally, to control or limit distribution of Ephemeroptera (mayflies)Plecoptera (stoneflies), and Trichoptera, (caddisflies), in Goldstream Creek. Ephemeroptera, Trichoptera and Plecoptera composed 90.8%, 9.1% and 0.1% of the total number of organisms collected during the sampling period. Only fourteen stoneflies were sampled and this proved to be too small a number from which to draw any conclusions. Trichopterans occurred in highest numbers in areas not heavily populated with Ephemeroptera. The station where the largest total number of caddisflies were collected had the highest water velocity and was the furthest downstream station. Normal downstream changes in water quality such as increased temperature, solids, color and turbidity, and decreased dissolved oxygen are also suspected to influence this separation of the mayflies and caddisflies. At the station with highest water velocity the caddisflies distributed themselves so that the numbers collected were inversely related to water velocity.