The State of Donner Lake

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The State of Donner Lake

INVASIVE SPECIES, WATER QUALITY TOP CONCERNS

BY PRIYA HUTNER

LEFT: Winter snow on Donner Lake. | Priya Hutner. RIGHT: Divers in the water preparing for the 2022 Donner Lake cleanup. | Clean Up the Lake

Sitting by the shore of Donner Lake this past summer, I watched pieces of trash float toward the edge of the lake and wash up against the algae-covered rocks. I didn’t recall seeing this much algae in years past. The green slime had crept up the wooden dock pylons. The rocks near the shore were bright green and dangerously slippery. Trash left around the lake has become the norm. Now covered in snow, the algae are gone and any residual trash is buried until spring. Trash and algae are two of the most visible impacts on Donner Lake, one of the jewels of Truckee and a highly popular recreation area. What isn’t as readily seen are the invasive Asian clams and crayfish that have doubled in the last decade, along with the impacts of erosion and runoff on the water quality. Within its 8 miles of shoreline is the popular Donner Memorial State Park with public beaches and 154 camping sites; the private Tahoe Donner Beach Club Marina; two private boat launches; one public boat launch; the public West End Beach; and 37 public piers and 225 private piers around the lake. On Dec. 7, I attended an open house hosted by a newly formed group, Donner Lake Inter-Agency Partnership for Stewardship (DIPS), facilitated by Foriver-Truckee River Watershed Council. The organization is a multi-agency partnership focused on protecting the lake. The organization has identified some of the critical issues affecting Donner Lake. The evolving stewardship plan, now in the works, will be designed to protect the future health of the lake. “We’re really interested in data. We hired a limnologist from [University of Nevada, Reno] to explore the state of Donner Lake. We’ll create a monitoring plan to study general attributes, chemistry, biology, water quality and things like that,” says Michele Prestowitz, project director of Truckee River Watershed Council. She adds that over the years, there hasn’t been consistent data collected about the lake. Donner Lake is part of the Truckee River watershed and several tributaries flow into the lake including Summit Creek, Gregory Creek, Billy Mack Canyon Creek and numerous springs.

Top concerns for Donner Lake

According to the State of Donner Lake report created by UNR’s Global Water Center among the most troubling findings is that invasive Asian clams have spread significantly over the past decade, as have the number of invasive crayfish. The report also mentions that two species of native fish, the mountain whitefish and Paiute sculpin, are no longer observed in Donner Lake. Water quality in the nearshore habitat is also degrading, which is impacted by the presence of invasive species and sediment runoff into the lake. “One thing that we were quite surprised to see is that the offshore water quality in the center of the lake has actually improved since the 1960s. But the nearshore habitat and water quality appear to be degrading. It appears that the biology is changing,” says Prestowitz. Like Lake Tahoe, Donner Lake also has an invasive mysid shrimp population, which is one of the main culprits linked to degrading water clarity in Tahoe. However, unlike in Tahoe, the mysid have not yet consumed all the native Daphnia, a zooplankton that helps clean the water. However, this could change over time if water quality continues to degrade and growth rates of plankton change, according to the report. Current mitigation efforts to keep additional aquatic invasive species out of Donner Lake include mandatory boat inspections for all watercraft entering the lake. Inspections are offered for motorized craft throughout the summer and a self-inspection program is in place for paddleboards, kayaks and other nonmotorized craft. “Our police department has a boat out checking for [inspection] stickers over summer. The Truckee-Donner Recreation and Park District [TDRPD] also provides staff at the public boat launch. Although TDRPD owns the public boat launch area, multiple agencies are involved in the prevention of aquatic invasive species through the current program. The two other boat launches are privately owned by HOAs and monitored by their staff,” says Bron Roberts, communications program manager for Town of Truckee in an email to Tahoe Weekly.

More trash reported

The nonprofit Clean Up the Lake completed a second cleanup of Donner Lake in the fall of 2022, collecting 7,379.5 pounds of garbage. During the first cleanup in 2020, the group pulled 5,151 pounds of garbage from the lake. The group has removed about 13,000 pounds of small pieces of submerged litter and 156 tires — and there is still a significant amount of litter in the deeper parts of Donner Lake, according to the group. “As we are monitoring the lake, we’re finding some hotspots that are definitely really dirty, like the area in front of the Tahoe Donner marina and the east end of Donner,” says West.

“One thing that we were quite surprised to see is that the offshore water quality in the center of the lake has actually improved since the 1960s. But the nearshore habitat and water quality appear to be degrading. It appears that the biology is changing,” — Michele Prestowitz

Read the State of Donner Lake report at bit.ly/donnerlake

He noted that that garbage ends up on the east end of the lake due to high winds from Donner Summit. According to West, it’s hard to say if Donner is dirtier, but more litter has made its way into the lake two years after their initial cleanup. “We found a significant number of larger items that we pulled out. One thing we saw was in the shallower zones and along the public piers was a significant amount of micro-, meso-litter [small pieces of trash and plastic],” says West. He also attributes the lack of trash cans at the 37 public piers on the north shore as a factor in the amount of trash the group collects. “I think if there were more litter management on that side of the lake for people to dispose of litter, it would probably be pretty helpful,” he says. The Truckee-Donner Recreation and Park District, which manages the public facilities around Donner Lake, reported that the presence of trash cans made the situation worse. “We had trash cans before along the piers and a big Dumpster at the boat ramp. People left couches and refrigerators by the Dumpster,” says Steve Randall, general manager for TDRPD and a member on the core team of DIPS. The district then removed the trash cans citing that trash was blowing into the lake. Clean Up the Lake divers have also reported a significant amount of algae in the shallow zones around the Lake during the fall cleanup, another concern highlighted in the State of the Donner Lake report. West says that his top three concerns for the lake are submerged litter, the need for public trash cans and water quality/lake clarity. “Everyone is concerned about recreation. We need to look deeper to find out what are some of the root causes of any kind of degradation in the area,” says Prestowitz, who points out that Donner Lake is an urban lake surrounded by roads and development. When asked, Town of Truckee’s Roberts acknowledges that it is difficult to choose the top three concerns for Donner Lake. “One challenge is reaching the right balance between providing equitable access to the lake and protecting it and its environmental, cultural, recreational and community resources. Another is educating both our residents and visitors on how we all need to play a part in protecting and enhancing the lake,” said Roberts by email. As an urban lake, pollutant sources include roads, highways, the railroad, commercial and residential development, increased visitation and recreation. Aquatic invasive species threaten the ecology, economy and recreation at Donner Lake. Climate change, shifting precipitation patterns, increased wildfires and excessive soil erosion also threaten the ecosystem’s resilience. While DIPS and UNR plan to continue monitoring the lake, the organization is asking for the public’s recommendations to protect the state of Donner Lake. Recommendations and suggestions may be emailed to Michele Prestowitz at mprestowitz@truckeeriverwc. org. n

Algae along the shore. | Priya Hutner

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