How Conserving Cougar Island Could Impact Entire Payette Watershed

Examining how conserving the state endowment lands around Payette Lake - including Cougar Island- could protect not only Big Payette Lake but the ecology of one of Idaho’s most prized watersheds.

By United Payette

As the future of Cougar Island is deliberated, United Payette continues to campaign for its conservation. 

While the island may only occupy a small portion of acreage of Lake Payette, this island -exemplary of all of the Payette Endowment Lands (PEL) - holds a value far greater than simply their “mass.” 

The Formation of Big Payette Lake - 

Big Payette Lake appeared in the late Pleistocene epoch when glaciers carved its basin from the earth, leaving behind the ridge that forms the present south shore where McCall is located.

The lake contains about 157 billion gallons of water and covers an area of 7.6 square miles, or 4,800 acres. It spans over 6 miles north to south, with a shoreline of over 22 miles. Depths exceed 300 feet in the northeast and southwest basins. The entire watershed is roughly 144 square miles, much of which is managed by the US Forest Service and Idaho Department of Lands.

Importantly,  Big Payette Lake is the sole source of drinking water for the City of McCall and hundreds of lakeside residences.

Water Quality - 

Just last year, Boise Dev reported that the Idaho Department of Environmental Quality (IDEQ) was ‘urging caution’ after lab tests showed cyanotoxins in Payette Lake’s North Beach lakebed. BoiseDev had previously reported that the DEQ was testing three areas of Payette Lake for cyanobacteria after a dog became ill. Test results from the northwestern area of the lake, a section between Brown Park and Mile High Marina, and the western edge of North Beach did not ‘reveal any toxins’.

 However, National Department of Environmental Quality test results revealed a different type of cyanobacteria in North Beach. 

“Test results indicated that the North Beach benthic cyanobacteria—also known as bottom-dwelling cyanobacteria—contain low levels of cyanotoxins but may still cause illness if directly consumed,” a Department of Environmental Quality (DEQ) news release said. “Cyanotoxins produced by benthic cyanobacteria are not typically identified using standard lab tests.”

While responsible development is certainly possible, this could be difficult for Cougar Island and for much of the shoreline surrounding Payette Lake. Cougar Island has been split into five parcels. There is currently one leased cottage site including a house on Cougar Island. This leased parcel along with the four other parcels will potentially be up for sale by the Idaho Department of Lands through public auction. 

The geology suggests that there's little buffering capacity to prevent sediment and nutrient runoff from entering the lake. The island lacks plumbing and electricity, and transportation of materials, fuels and equipment from the mainland to the island present additional risks,” explained Big Payette Lake Water Quality Council President David Simmonds. “There is likely no available dock or beach landing for such transportation, as the existing leaseholder seems to occupy the only suitable beach / dock site on the island. The shoreline is dominated by rock and disruption of that natural buffering through construction access and activities could accelerate the release of organic material into the lake.”

Studies have shown that genes associated with nitrogen and phosphorus metabolisms played important roles in cyanobacterial outbreak formation.

“Payette Lake is experiencing near-shore algae problems on a somewhat annual basis now, with elevated total phosphorus in the near-shore water column appearing to be a primary culprit. Shoreline erosion and shoreline runoff are suspected as primary contributors but University of Idaho study results are not yet available,” Simmonds continued. “IDEQ (specifically Chase Cusack) may be the best resource for current monitoring information. Development impacts on Cougar Island could be expected to contribute to these problems, and mitigation is likely to be more difficult than on mainland building lots due to geology and access challenges.

Cyanobacteria and the cyanotoxins produced by them can be dangerous for humans, wildlife and fish. 

Fish, Wildlife - 

Comprising three lakes including Payette Lake, Little Payette Lake and Upper Payette Lake, Payette Lake (5337 acres) are destination fishing locations for cutthroat trout, rainbow trout and more. In addition, Idaho Fish and Game reports that old-growth lake trout planted in the 1950s can weigh more than 30 pounds. Little Payette Lake (1450 acres) has a good population of trophy smallmouth bass.

The Center for Disease Control clearly states that algal outbreaks caused by cyanobacteria can be harmful to fish by decreasing oxygen levels in the water, and that cytotoxins will directly cause fish kills. 

In an already delicate ecosystem hosting a diverse range of species, additional environmental stressors do not seem like a risk worth the reward. 

Protecting The Headwaters - 

A crucial element to consider when evaluating potentially risking the water quality and delicate ecology of Payette Lake is its role as the major headwater basin of the entire Payette watershed. 

For example, while other reservoirs in the Payette watershed such as Cascade Lake are not sources of drinking waters, Cascade Lake lake hosts world-class perch fishing, particularly during the winter months, attracting sportsmen and women from around the world. This, not to mention intensive recreation access during the summer, is at risk if algae outbreaks and presence of cyanotoxins continue to increase. 

On its website, Idaho Fish and Game states “The risk associated with consuming fish caught in waters with a blue-green algae bloom is unknown. Toxins produced by blue-green algae can accumulate in the organs of fish." 

United Payette believes that maintaining the largely pristine and intact ecosystem of Lake Payette by conserving Cougar Island from private development offers value to the Payette Lake community and downstream Valley County. 

The risk of private development opens the potential for negative impacts that could impact the health of the citizens, the recreation economy and the bustling ecosystem of not only McCall, but the entire Payette River and National Forest community.