Answer:
Step-by-step explanation:
Clean water from streams and rivers that flow into the Salish Sea is essential for maintaining a healthy ecosystem. Excess nutrients, warmer temperatures, and other factors can create water quality problems in lakes and streams that impact the entire ecosystem.
A Freshwater Quality Index (WQI) is tool developed by scientists to help evaluate the quality of water in these streams and rivers. It summarizes large amounts of water quality data into a single "score" from 1 to 100. Higher scores reflect cleaner water.
Learn more about Freshwater Quality Indexes
Sustainable Perspectives
"The Skokomish Tribe is wholly devoted to restoring the Skokomish watershed and its resources -- not just for the next five years, not just for another 40 years, but forever. We must continue healing the environment that we depend on for survival. The health and well-being of the Skokomish watershed is vital to the Skokomish tribal culture, tradition, subsistence and economy."
Joseph Pavel, Skokomish Tribe
Between 1858 and 1870, the fur trade gave way to the gold rush as gold seekers flooded the Fraser River Basin. Coined the "hungry people" by the Sto:lo, gold seekers made their way up the Fraser River, bringing mining, road construction and boom towns to the region, impacting salmon spawning habitat and reducing water quality.
To separate gold from sand at Fort Hope, standard mining operations used 40 to 50 pounds (18 to 23 kilograms) of mercury a day, while smaller operations used 8 to 10 pounds (4 to 5 kilograms). Today, beads of mercury (or "quicksilver") can be found by digging down only a few feet into the sands of Emery's Bar.
The impacts of mercury on sturgeon and other aquatic life - as well as First Nations who depend on them - have yet to be studied.
Source: Keith Thor Carlson, Sto:lo - Coast Salish Historical Atlas
What's happening?
The average Freshwater Quality Index scores for 17 major rivers in the Salish Sea watershed from 2000 to 2010 show that:
Five rivers have good to excellent water quality (80-100).
Seven rivers have marginal to fair water quality (70-80).
Five rivers have poor water quality (below 69).
Why is it important?
Clean, cold water is critical for streams and rivers where salmon spawn. Even small changes in stream temperature can impact salmon populations.
Poor stream quality can also impact marine water quality by introducing chemical and pathogenHelppathogenA disease-causing microorganism. pollution, nutrients that can result in algal blooms, and lowering oxygen levels in areas where these streams empty into the sea.
Drinking water, irrigation, recreation, and other uses can also be affected by poor stream quality.
Why is it happening?
Three major factors that affect freshwater are:
Stormwater runoff due to increasing development of roads, traffic, parking lots, and other paved areas.
Loss of riparian and wetland areas along streams due to development and agricultural operations.
Loss of forested areas in the upper watersheds due to timber harvesting.
Recent studies have shown that stream quality can be affected if as little as 7% of the total watershed area is covered by impervious surfaces (e.g. paved areas).
Likewise, the amount of vegetation also plays a role in stream quality. Impacts to stream quality can be observed when vegetative cover (e.g. forested areas) has been reduced to less than 65% of the total watershed area.
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