Flaming Geyser State Park is a gem within the Washington State Park system. Located just outside of Kent, Auburn, and Black Diamond, the park offers easy access to the Green River along with a variety of recreational opportunities and has special significance to the Muckleshoot Tribe.   

Flaming Geyser State Park’s location along the Green River also makes it an important site for continued riparian restoration efforts within the broader Green River watershed. Unfortunately, sections of the Green River do not meet some of the state’s standards for clean water.  

Today's conditions in the Green River are the result of a 150-year history that includes timber harvests, land clearing for agriculture, urban and suburban development, major water diversions, water withdrawals, and flood control activities. Some of these activities have impacted watersheds throughout the Puget lowlands but others are specific to the Green River, such as diversion of a major tributary (the White River) into a different watershed, the loss of inflows from Lake Washington after the construction of the Ship Canal, and the construction of the Howard Hanson Dam to reduce flood risks to agriculture and urban areas. In addition, the Green River contains a substantial system of levees in the middle and lower parts of the river.   

The results of these of these modifications to the Green River have provided economic benefits to the Puget Sound region. However, these modifications to the river and the broader watershed do not come without side effects. The loss of the river’s connectivity to the floodplain, additional warm water inputs from tributaries that have undergone similar changes, decreased groundwater inputs to the river, and loss of native riparian vegetation have all contributed to the river being warmer and having low levels of oxygen. 

Supporting Green River restoration 

We assess and improve water quality through the development of Total Maximum Daily Load (TMDL) improvement plans or water clean-up plans. The overarching goal of the Green River temperature TMDL is to reduce water temperatures and improve water quality for salmonids including Chinook, bull trout, and steelhead, which are listed as threatened under the Endangered Species Act.

The TMDL for the Green River recommends extensively revegetating riparian shorelines to address high water temperatures. The 2011 temperature report showed that there is about a 2 degree Celsius (3.6 degrees Fahrenheit) increase in river temperature between the Green River Gorge at Flaming Geyser State Park and the mouth of Newaukum Creek, 2.5 miles downstream. Some of this temperature increase may be attributed to the shoreline within the state park that is mostly without trees.  

In the past decade, federal, state and local government partners have focused their efforts on restoration in the Green River watershed through a variety of partnerships with King County, Midsound Fisheries Enhancement Group, Green River Coalition and the cities of Kent, Auburn, and Tukwila.  

In 2021, King County submitted an application to Ecology’s Water Quality Combined Funding program for riparian restoration work along the river within Flaming Geyser State Park. In 2022, Ecology awarded King County $450,000 over three years to restore at least eight acres of riparian habitat along the Green River shoreline at Flaming Geyser State Park. This funding is only for restoration on King County-owned lands within Flaming Geyser State Park as Ecology’s Combined Water Quality Funding Program does not fund work on federally or state-owned lands.  

We spoke with Josh Kahan, King County's Project Program Manager for the Green River and White Basin, to hear more about why bringing more native plants to the state park is a priority for clean water:

“We're finding that the water temperatures of the Green River as it flows through the cities of Auburn and Kent, can become lethal for salmon at certain times of the year. This can negatively affect the rearing portion of the salmon life cycle, which is when young fish grow to a large size prior to migrating out of the watershed. These high temperatures have to be addressed further upstream at places like Flaming Geyser State Park and streams that feed into the river.”  – Josh Kahan, King County

What does riparian restoration look like? 

Riparian habitat restoration at Flaming Geyser State Park will increase shade along the river, provide habitat connectivity for aquatic species, and restore habitat for upland species like deer, elk, and songbirds. 

King County is planting a minimum of 8,000 native trees and shrubs, including a variety of shade-producing native trees such as bigleaf maple, black cottonwood, Douglas fir, western red cedar, Sitka spruce, and black hawthorn. Native shrub species include Nootka rose, snowberry, ocean spray, serviceberry, mock orange, and willow.  

As Josh Kahan with King County explains, it takes time and patience to see the full impact of restoration projects.  

“The native plants we do first establish are generally very small. So, if people were coming out here 20 years from now, they would see a completely different scene than what they see today. They would see trees that are 30 to 40 feet tall. They would see tons of shrubs and of different varieties, and they probably wouldn't be able to see very far. Right now, we can see probably a mile in length from where we're standing.” – Josh Kahan, King County 

King County will monitor and actively manage the riparian buffer restoration site for 10 years, which includes clearing competing vegetation around plantings, preventing re-establishment of invasive species, and summer watering.  

Riparian restoration work is an ongoing process and requires vigilance and patience. Results are not obvious at first glance. With each season, as native vegetation reestablishes itself and stream temperatures slowly stabilize to cooler conditions, the changes are visible. 

Learn more about clean water funding 

Our clean water funding program is a streamlined, statewide program that allows a variety of grant applicants to access funding for water quality improvement projects. We accept applications every year. The application cycle recently closed and we look forward to announcing our draft funding offer list in January 2025. Visit the water quality grants and loans webpage to learn more.