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The "Hardrock" Study:
Science leading the way on environmental policy

A recently released decade-long study looking at several aspects of water quality, including temperature and sediment, show that current forest practices rules as outlined in the Forests & Fish Law are protective of fish.

Beginning in 2007, the study (informally known as “Hardrock”) measured temperature, sediment and other parameters of water quality three years before a harvest on forestland that is home to non-fish bearing waters that flow into fish bearing waters. Then, for nine years after harvest and during the period of replanting and regrowth, the study continued to measure the same factors related to water quality. Temperatures, specifically, were measured at the height of summer in July and August.

The study found that while there was a small, temporary thermal pulse (averaging 1.2 degrees Celsius) immediately after harvest, stream temperature never exceeded the 16 degrees Celsius threshold established by the Washington Department of Ecology for the most common temperature standard found on private forest lands.  Temperature never exceeded 14.2 degrees Celsius – nearly 2 degrees Celsius below the temperature science agrees is needed for the survival of fish including salmon.

The study represented an extreme case for harvest than is common. Landowners rarely harvest an entire basin leaving only the buffers – strips of trees and other vegetation left adjacent to the streambanks for the purpose of mitigating the impacts of the harvest nearby – required under current rules. But such a harvest could happen within current rules, the study was designed to press against edge of that possibility.

The study also focused on streams with bedrock stream beds, a type of lithology commonly referred to as “hardrock”.  A similar study focusing on “softrock” streambeds is expected to produce similar results.

The current forest practices rules are the result of the historic Forests and Fish Law that was adopted into law nearly 22 years ago by the legislature and signed into law by Gov Gary Locke.  Not only did the Forest and Fish Law create the most fish-protective rules on private forestlands in the nation, but the landmark law also established a highly effective Adaptive Management program for studying the effectiveness of rules and adjusting them if inadequacies were found.  So far, very few rule changes since the 1999 agreement have been necessary, demonstrating the effectiveness of the agreed rules.

Where's public opinion?

Residents of Washington's most populous county: happy about progress on upstream water quality, hungry to see similar success downstream.

In a June 2022 poll of statewide voters, 67% agree that water quality and temperatures in upper watersheds is healthier for salmon than in lower watersheds…

… 78% believe that state government should make lower watersheds a bigger priority …

… and 68% of voters statewide believe private forest landowners protect water quality on their lands.

Download the entire report.

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