When in freshwater, coho salmon feed on plankton, insects, and larval invertabrates, but swtich to a diet of small fish upon entering the ocean. To regain these fish, Bowker Creek needs to have conditions to support populations of plankton, invertabrates and insects - such as stable water quality and ample food. Here are examples of such sources. 

Currently, a restoration process is taking place in Bowker Creek. The goal is to bring back the naturality of it, and hopefully bring back some species that once roamed those waters. Here is a video explaining the restoration!

A majority of Bowker Creek is underground, this could alter the possibility of sustaining plankton or zooplankton in the creek as they use photosynthesis to create food and would need to live in open areas of the creek where sunlight is available. As for aquatic insects, Bowker Creek is riddled with them! Aquatic insects would not be an issue here!

The Chum and Coho Salmon have a very similar diet. They both feed on aquatic insects and plankton, however, the Chum Salmon specifically feeds on zooplankton rather than Chum Salmon that eats all and any plankton available.

My peers have created a playlist going into further detail on how to get the salmon back! I highly recommend you check it out!

I calculated the statistics between both the salmon types and determined a shared level of tolerance/necessity of each category. Above is the information displayed in a chart I created. 

Here is a video of Chum Salmon spawning! A hopeful result we can achieve in Bowker Creek!

Above is a chart comparing the tolerance and necessary amount of different molecular substances found in the creek. This table is able to tell us that the water quality of Bowker Creek is not yet able to sustain Chum Salmon.