Water Quality Improvement Project
The Green Diamond Resource Company, formerly known as the Simpson Timber
Company, is a forestry company in the Pacific northwest.
Water quality issues
Several tributaries of the lower Chehalis and Skokomish rivers on
Green Diamond Resource Company land, as well as several streams draining to
South Puget Sound and Hood Canal, do not
meet the state surface water quality standards for temperature. High
summer water temperatures in some of these streams affect the rearing habitat for coho salmon as well as for steelhead and
Why this matters
Water temperature influences what types of organisms can live
in a water body. Cooler water holds more dissolved oxygen that fish
and other aquatic life need to breathe. Warmer water holds less
dissolved oxygen. Threatened and endangered salmon need cold, clean
water to survive.
Land use activities that can cause surface water
temperature increases include forest management within riparian areas,
timber harvest in sensitive areas outside the riparian zone, and roads. One way to cool water temperature is to shade the water body by adding or
retaining streamside vegetation.
Status of the project
This TMDL was established for two pollutants: heat (incoming solar radiation)
and sediment. It addresses four water quality-impaired segments listed on the
1996 303(d) list for temperature. These segments are within Green Diamond
Resource Company’s 261,575 acres
of Northwest Timberlands. The TMDL sets allocation limits to protect all 1,398
miles of the area streams from becoming impaired.
This TMDL is unique because it limits the physical scope of the
TMDL to land ownership, rather than try to expand to cover all of the affected
watersheds. Parameters were also limited the to those heavily
impacted by forest management activities. A single landowner offered to
coordinate their forest land management planning with development of the TMDL.
Ecology submitted the TMDL report to EPA, which approved it in July 2000. The TMDL implementation strategy was designed to support long-term monitoring
and implementation activities.
Simpson Northwest Timberlands Temperature Total Maximum Daily Load -- Submittal Report (Ecology publication)
Simpson Habitat Conservation Plan (HCP)
Cross-walk between HCP and Forest Practice Rules (updated)
Ecology publications pertaining to WRIA 22 (Ecology publication)
WRIA 22 Watershed Information (Water website)
WRIA 22 and WRIA 23: Chehalis Basin and Nearby Drainages: Salmon
Habitat Limiting Factors (WA State Conservation Commission)
Back to top of page