According to this video, the grade lead stabilization is designed to help fish like salmon easily make it upstream to manage the populations. Lead stabilization also works to manage the amount of lead that gets into the stream, reducing the amounts and creating a safe and healthy environment for the fish. The slopes that are made in the streams are done at gradual intervals, which makes it more conducive for the smaller fish who may be having a harder time getting through the stream. A weir was introduced at each slope to keep the shape for several decades/
Before the stabilization, there was a culvert that was manmade and used as another way to help manage the flow of fish in the stream.
The damage from these culverts can impact the environment for the fish and even restrict their ability to flow through over time. There is also the chance of higher lead concentrations, which isn’t an issue with the slopes that are gradually graded. With lead stabilization, the amount of lead entering this environment is reduced and will continue to be lower in numbers for decades to come because of this new method. Culverts that are replaced are often larger to make room for more fish to swim and are also used with different materials to reduce the amount of lead.
