The Importance of Pyramid Lake Water Quality

There are a lot of reasons our watershed is unique. It’s a high elevation terminal watershed, what could be more special? Well, another contributing factor is that the terminus of the Truckee River watershed exists on the largest Native American Reservation in Nevada.

That’s right! The Pyramid Lake Indian Reservation (PLIR) consists of 742 square miles of land and Pyramid Lake is smack dab in the middle of it.

Both the Truckee River and Pyramid Lake hold vast historical and cultural importance to the Pyramid Lake Paiute Tribe, so it isn’t surprising to learn they are already heavily invested in water quality monitoring and restoration projects. Their water quality monitoring program began in 1981 on Pyramid Lake and in 1998 on the lower Truckee River within the reservation’s boundaries. Since then, the team members working on the reservation have become leaders in water quality and frequently provide guidance to other tribes with younger programs.

But, before we get into the various water quality protection programs, let’s get into why we need them…

History of Water Quality at Pyramid Lake

Similar to how pollution tends to accumulate in the world’s oceans, Pyramid Lake usually feels the brunt of the impacts from pollution and other changes upstream in our watershed. And over the last century, the Truckee River watershed has seen a myriad of transformations.

Hydromodification

One of the most impactful changes made to the Truckee River was the hydromodification and channelization of the river by the Army Corps of Engineers in the 1950s and 1960s. This was driven by the historical understanding of water resources as a liability for flooding and therefore being a risk to city infrastructure upstream in Reno and Sparks. However, straightening out the river came with other repercussions. Rivers aren’t meant to move in a straight line, they naturally meander, so channelization just led to more erosion as the river tried to break out to its floodplains. As a result, erosion and deforestation caused a loss of the legacy cottonwoods along the river, allowing for invasive species to take hold and causing much of the lower river to be impaired for temperature due to lack of shade.

Cottonwood recruitment has significantly improved in the last 30 years due to careful monitoring and adjustment of river flows; however, temperature and turbidity continue to be problems for the Truckee River.

Other types of hydromodification, like dams, also tend to have both upstream and downstream implications. For example, the Derby Dam, which diverts water from the Truckee River to the Lake Lahontan Reservoir for irrigation, resulted in ¾ of the Truckee’s flow not reaching Pyramid Lake through parts of the 20th century, just 25 miles downstream. The dam also resulted in Lake Winnemucca completely drying out and caused the extinction of the original Lahontan Cutthroat Trout strain. This necessitated the installation of a fish elevator at Marble Bluff Dam so native fish could reach their spawning grounds. Since then, flows have been managed to support the fish in Pyramid Lake and lower Truckee River.

Pollution Impact

As you may know, there are also various pollution risks introduced along the Truckee River, and they all have the potential to reach Pyramid Lake.

One of the lake’s greatest threats is Total Dissolved Solids (TDS), which comes from effluent discharge from groundwater seepage of agricultural lands in nearby Fernley. TDS is a measure of the combined total of organic and inorganic substances in the water, and is a major problem for the protected fish living in Pyramid Lake. Both the cui-ui and Lahontan cutthroat trout have a threshold for tolerance of TDS, putting this issue high up on the list of priorities for water quality standards. Other pollutants resulting from effluent discharge include phosphorus and nitrogen, stimulants for algae growth causing diminished dissolved oxygen in the water.

There are other stormwater impacts as well (check out our blog on stormwater for all details), but we’ve already covered the most consequential of the pollutants.

Water Quality Program

Even though Pyramid Lake has plenty of threats, the reservation has a robust water quality program supporting both the lake and the river’s health. And behind all of the programs implemented are the water quality standards the tribe is striving to meet. They recently revised their standards to ensure they are effective with a concentration on nutrient loads (phosphorus and ammonia), lake clarity, and bacteria.

Water Quality Monitoring

The Water Quality Program is supported through the federal government by the Clean Water Act (Sec. 106 to be specific) and since its inception in 1981, the program has consistently increased program capacity and now gives the tribe a comprehensive understanding at how the lower watershed is faring at any time of year.

Water Quality Monitoring Sites at Pyramid Lake

Currently, the monitoring program consists of two sites on Pyramid Lake, one deep station monitored monthly in the northern part of the lake and one shallow station monitored quarterly in the south; five sites along the lower Truckee, monitored monthly; five non-point source sites within the reservation and along with 13 perennial streams; and two continuous monitoring sites. Data collection at these sites is “multi-parameter” monitoring. So they’re measuring pH, temperature, dissolved oxygen, TDS, and salinity, AND collecting samples to analyze for various non-point source pollutants like the different forms of nitrogen and phosphorus.

There is also regular monitoring for cyanobacteria in the lake for the recreation season and the tribe is prepared to provide public notice if there is potential for a harmful algae bloom.

Wetland Restoration

One of the most admirable aspects of the tribe’s Water Quality Program is they never stop evolving. Every year they apply for new grants to extend their reach and then incorporate the new programs into their yearly agenda. One example of this is their Wetlands Program, which is funded by the Region 9 U.S. Environmental Protection Agency’s grants.

With 22 existing wetlands on tribal land and other areas requiring restoration, the tribe’s work with wetlands has become a two-fold undertaking. One side is the restoration component, which has already seen two successful projects. The Tile Drain constructed wetland is providing water quality benefits, as water passing through it is seeing an almost complete reduction in nitrogen; the constructed and restored Numana Wetland is seeing similar success through treatment of nearby fish hatchery water. All of this is captured in monthly monitoring conducted for non-point source pollutants. They also provide habitat for many native animals and plants.

Tile Drain Wetland Before/After
Tile Drain Wetland Before/After

The other component of their Wetland Program is water quality and habitat monitoring. In early spring, the tribe conducts “bioassessments,” or CRAM assessments, on all of the wetlands within the reservation to gather data on their health. Recently they have been focusing on monitoring native leopard frogs in their assessments and determining where the frog could potentially be reintroduced.

One of their next wetland demonstration projects will focus on invasive weed species removal. The specific focus will be the perennial pepperweed, which is notoriously difficult to eliminate once its established. The intended method for removal is to solarize the weed and reintroduce native vegetation over the course of a few years.

New Aquatic Invasive Species (AIS) Program

Following the trend of adding to their monitoring and prevention programs, the tribe has introduced the Aquatic Invasive Species (AIS) Program. To avoid introduction of invasive mussels and other non-native species to Pyramid Lake, all watercraft will be subject to inspection and decontamination (if needed) before entering the water. While this may seem like a hassle to recreators, once species like Zebra Mussels have been introduced, they quickly become prolific in the water body and almost impossible to eradicate. Prevention really is the key here.

Other Water Quality Improvements

Before this blog post gets too long, we’ll quickly mention some of the many other actions being undertaken over at Pyramid Lake. They have also constructed livestock fences along the Truckee River, implemented revegetation and bank stabilization projects, and constructed permanent bathrooms around the lake.

With all that being said, let’s put our hands together for all the awesome work being done by the Pyramid Lake Paiute Tribe to protect both the Lake and the Truckee River.

Sources:

Nonpoint Source Management Plan Pyramid Lake Paiute Tribe of Nevada