The Pacific Northwest is home to five types of salmon: Chinook (King/Spring), Sockeye, Coho, Keta (Chum) and, Pink. Rivers fed by mountain springs empty into the pristine North Pacific Ocean across a spread that runs from the Alaskan peninsula, British Columbia, Washington and, Oregon. The salmon starts its life in nature-sculpted fresh water bodies at the foot of verdant evergreen mountains. As it turns into a silvery smolt (fingerling), it starts to make its journey downstream and emerge from the rivermouth to swim to the vast cold, deepwaters of the ocean. In the next 3-7 years, the salmon will make a circuitous journey, grow to adult size ranging from 4 - 20 lbs. A genetic trigger catalyzed by its attainment of sexual maturity will give the signal for the salmon to return to the river of its birth, to lay the eggs for the next generation of salmon. Thus, salmon runs (returning salmon) are conveniently referred to by the river of their birth, such as: Copper River Sockeye, Snow Pass Coho, Fraser River Sockeye and, the subject of this posting: the Capilano River Coho.
The Capilano River in the North Shore of the Greater Vancouver Region is home to a group of coho salmon. The river is fed upstream and starts at the foothills of the Lions' Head mountain. 
The waters of the Capilano are so clear and clean and safe that they have been deemed drinkable by a thirsty human population in the growing urban sprawl of the Lower Mainland. Snaking downwards in a nature-curved gully, it became convenient to trap the waters and build a reservoir now known as the Cleveland Dam. A 90-foot heavily reinforced concrete wall holds the water in the dam. This same structure blocks the path of the returning salmon to their spawning grounds, preventing them from fulfilling their genetic obligation to give birth to the next generation of salmon. The salmon will return regardless of the hurdle that awaits them, their bodies laden with eggs (for the female) and milt (for the male).
Enter the Canada Salmonid Enhancement Program which built the Capilano Salmon Hatchery just below the water drop of the Cleveland Dam.
The hatchery is designed to save the eggs of the salmon, hatch them from redds stage to alevin stage, feed them to grow into smolts, strengthen them to sturdy juveniles that will prepare them for their journey downstream and towards the ocean waters.
The returning adult salmon swim against the currents of the Coho Loop, an upstream portion of the Capilano River just before reaching the hatchery area. The salmon then are guided by a 9-foot spillway to swim towards a narrow concrete raceway referred to as the fishway in order to enter the hatchery premises. The very same waters from the dam flow down the fishway, allowing the salmon to recognize the water quality of their birth roots.
When the juveniles are finally released into the Capilano River, they pass under the water pipe that brings their river's water to the thirsty human population, navigate the shallow erosion laden river mouth, make a final pass under the train bridge and dash for the deeper waters of the Burrard Inlet that guides them to the Straight of Georgia upwards to the Queen Charlotte Sound and finally into the north pacific ocean.
Years later, when the salmon returns to the river of birth, their pathway has become the humans' boatway, the watershed that protects the river are slowly encroached and, their home has been turned into a tourist haven for nature lovers.
