By Peter B. Moyle

When Californians talk of lakes, they usually mean reservoirs, the 1500 or so artificial bodies of water behind dams. Alternately, they may be referring to the 4,000 or so natural lakes in the Sierra Nevada or to one of the few large natural lakes in the state, such as Lake Tahoe or Clear Lake. But some of the most interesting lakes in the state draw our attention mainly when demand for water threatens to dry them up. These are terminal lakes, that mostly depend on seasonal rain or snow melt to maintain them as lakes. They are called terminal lakes because water flows into the basins through streams, but leaves mostly by evaporation or sinking into underground aquifers. Each lake has its own unique chemistry and other characteristics, although most are highly productive so are important to migratory waterfowl and invertebrates. They may or may not support endemic fish populations. This blog is a brief introduction to the largest of these fascinating lakes in California. All are in need of management to protect their distinctive features and biota.

Terminal Lakes are huge phenomena that are underappreciated for their importance in California. Most famously, they include Mono Lake, Salton Sea, and Lake Tulare. But the term also encompasses Goose, Alkali (3 lakes), Eagle, Honey, Owens, Walker, Carson, and Pyramid lakes. The latter three lakes are in Nevada but largely drain watersheds in California. All these lakes have unique characteristics and are important features of the landscapes in which they occur. Geologically, they are mostly in endorheic basins where water flows in but not out.

Terminal Lakes are fed by streams and typically require high flow events to maintain their water levels. For the most part, water enters from streams and leaves by evaporation or by seeping into the ground. However, after multiple wet years, some may spill over basin boundaries and into a river system. Not surprisingly, terminal lakes are mostly found in desert environments, where inflowing waters are coveted for irrigation and other uses; diversion greatly increases the likelihood these lakes will shrink or dry up, especially during periods of drought.

Table 1. Characteristics of ten terminal (endorheic) lakes of California (and Nevada). Area is surface area assumed to be typical before diversions prevented most inflow from reaching the lake. Historically, all varied in area and depth in relation t­o precipitation variations.

Terminal lakes were of major importance during the Pleistocene Period. Then, heavy rainfall resulted in much of the Great Basin being covered with enormous lakes, including Lake Lahontan in Nevada and California east of the Sierra Nevada. At times, much of the Central Valley must have been flooded as well. The lakes in Table 1 are mostly remnants of these ancient lakes, which during wet periods connected with other lakes.

What follows is a brief introduction to each these lakes. Jay Lund (Lund 2023) and I (Moyle 2023) have already blogged about Lake Tulare, so it will not be treated further here.

Goose Lake is an immense lake (elevation 1433 m) that straddles the Oregon border; most of its watershed, and most of the water that historically flowed into the basin, is in Oregon. The lake goes dry naturally during periods of extreme drought, but the frequency of drying has increased presumably because of diversion of the water for agriculture (Heck et al. 2008). It has gone dry in 1851-2, 1926, 1929-34, 1992, 2002, 2013-15, and 2020 (Goose Lake Wikipedia).

Goose Lake has an endemic fish fauna (nine species) that find refugia in the inflowing streams and ponds in the basin when the lake dries up (Moyle, unpublished 1992). In 1989, I spent several days sampling the lake’s fish population during a wet period (since 1934!) with then graduate student Rollie White. Sampling was challenging because the lake was so shallow and strong winds came up every afternoon, which kept the lake turbid and unsafe for boating. We confined our boat sampling to nights and calm early mornings, using a variety of sampling gear. I was impressed with the abundance of fish, especially Goose Lake tui chubs. When we pulled in our gill nets, many of the tui chubs had small (10-12 inches) lampreys attached while others had round sores on the body where lampreys had been attached. The undescribed Goose Lake lamprey was a beautiful bronze color, that glowed in the sun. Also captured in abundance were tadpole fairy shrimp (Figure3), which are usually not found in waters containing fish.

A fish we did not catch was Goose Lake redband trout (see photo), which migrates up streams from the lake to spawn. Stream populations have been the focus of conservation, including Lassen and Willow creeks in California. Historically, this fish maintained fairly large populations in the lake and inflowing streams, which supported a lake fishery during wet years (Moyle et al. 2015). In 1992, USFWS proposed listing all Goose Lake fishes as ‘Threatened’ as the lake dried up (Moyle 1992). The proposal to list the species was withdrawn after local ranchers agreed to work with state and federal  agencies to allow assessment status on private lands.

The Alkali Lakes are three connected lakes occupying the floor of Surprise Valley, California. The ‘lakes’ are mostly dry salty flats that can flood with shallow water in winter but typically dry out in summer, a pattern enhanced by diversion of inflowing streams to irrigate alfalfa fields. The lakes are one of the many remnants of Pleistocene Lake Lahontan. It is always a surprise to see the valley with its white alkaline (mostly dry) lakes and contrasting green fields of alfalfa, while crossing the Warner Mountain range. The aquatic fauna of the region is poorly characterized although inflowing streams contain apparently endemic fishes in Nevada.

Eagle Lake is second largest freshwater lake entirely within the boundaries of California. Once connected to Pleistocene Lake Lahontan, the lake today is supplied by water from Pine Creek and a few smaller creeks and springs.  The lake is at a high enough elevation (ca. 5100 ft) and is large and deep enough, to be characterized as a cool water ecosystem with a freshwater fauna. The water is nevertheless fairly alkaline (pH around 9); thus most ‘true’ freshwater fishes are excluded from it, including the alien species that are so abundant in most California lakes and reservoirs. Instead, the lake supports five endemic fishes that are specifically adapted to its unique chemistry. Four of the species have ancestors that inhabited Lake Lahontan, but the Eagle Lake rainbow trout has ancestors in the Sacramento system. This trout historically grew to large sizes because of abundant prey (tui chubs and invertebrates) and delayed maturity. The latter characteristic resulted in it giving rise to a hatchery strain that is widely planted in reservoirs around the state.  Eagle Lake also supports a substantial recreational fishery for Eagle Lake rainbows that is maintained by a hatchery rearing program. The high alkalinity of Eagle Lake also is an indication of its high productivity, with a food web that supports  breeding populations of waterbirds such as western grebes and osprey.

Honey Lake is another Lake Lahontan remnant. It is the large expanse of alkali flat, sometimes partially flooded but usually dry, that is visible from Highway 395, south of Susanville. It is surrounded by marsh lands, important for migratory waterfowl. These marshes are fed by three major tributaries: Susan River, Long Valley Creek, and Willow Creek. During the Pleistocene, Eagle Lake apparently drained into Honey Lake, via Willow Creek. Recognition of this ancient connection led to an effort in the 1920s to hew a tunnel through lava rock in order to provide more water for agriculture in the Honey Lake basin. Bly Tunnel was completed, but the water added to Willow Creek was too little to make it to Honey Lake (Moyle et al. 1991). Native fishes include desert speckled dace, Tahoe sucker, tui chubs, and Lahontan redside.

Pyramid, Walker and Carson Lakes. These three terminal lakes are in Nevada but their water originates in California, flowing down the Truckee, Walker, and Carson rivers respectively. Pyramid Lake is the largest and most spectacular remnant of Lake Lahontan and has an endemic fish fauna, most famously Lahontan cutthroat trout and cui-ui, which support Indigenous and recreational fisheries. Lake levels dropped dramatically when the Truckee River was diverted to irrigate alfalfa in the early 1900s. The lake was ‘saved’ when the cutthroat trout and cui-ui were listed as endangered species, the Paiute tribe asserted its right to water to maintain the fishery, and other factors came into play. Walker Lake also suffered from irrigation diversions taking the inflowing water, becoming too low and too alkaline to support fish populations, except in wet years. On-going litigation is aimed at restoring the lake and its cutthroat trout fishery. Carson “Lake” is usually not regarded as a lake but as a ”sink” although it occasionally becomes a short-lived lake (e.g. 1987). Like the other two lakes, it is a remnant of Lake Lahontan and has suffered almost complete depletion of its water supply from agricultural diversion.

Mono Lake is the best known of California’s terminal lakes because of its stark beauty, unique ecology, and being center of a David vs. Goliath environmental battle (Hart 1996). The battle, to simplify, was between a volunteer Mono Lake Committee and huge Los Angeles Department of Water and Power. LADP was in the process of drying up the lake by diverting the water from inflowing streams, which MLC wanted to stop. Joined by major environmental groups, MLC was largely successful, not only saving the unique lake and restoring the streams, but setting legal precedents that have had consequences far beyond the lake (e.g., Public Trust Doctrine). The MLC continues in its role as guardian of the lake and its biota, with headquarters in Lee Vining (overlooking the lake) and activist staff and volunteers. Those who want to know more about this history and about the amazing natural history of the lake, should go to the MLC website (info@monolake.org) and/or subscribe to their excellent newsletter.

Owens Lake. An important lesser-known story in the history of California is how developers in Los Angeles acquired, by nefarious means, the water flowing in streams of the Owens Valley and built an 223 mile long aqueduct to carry the water south. Starting in 1913, this diversion effectively dried up the streams, ending irrigated agriculture in the region. Less appreciated in this drama is that Owens Lake also dried up in the following years. This terminal lake had been a permanent body of brackish water, 25-50 feet deep, fed by the Owens River and was best known for its large populations of migratory and nesting waterfowl. Little is actually known about the ecology of the lake but the streams the fed it supported at least four endemic fishes, including Owens pupfish, which may have inhabited the lake as well.

An unexpected consequence of the drying of the lake was massive storms of toxic dust which spread over wide areas and were detrimental to human health. To control the dust, the City of Los Angeles was required to reflood much of the lake bed. Habitat for thousands of migratory birds re-developed, producing brine flies, brine shrimp and other fuel organisms for the migrating birds. The historic lake now exists as a shallow remnant, perhaps more similar to Mono Lake than to the original Owens Lake but dependent on pumping of water into the lake basin. However, in the snowy winter of 2023, there was more water than the LA aqueduct could handle, and large quantities flowed into the lake bed, at least temporarily resurrecting a less salty version of the lake.

Salton Sea is a salt water lake occupying the bed of long-dry Lake Cahuilla. The ‘sea’ was recreated in 1905 when the entire flow of the Colorado River, during a flood, burst through levees and flow into the Alamo Channel. Initially the ‘sea’ was a freshwater lake occupying the old lake bed. It became increasingly salty after the river was re-diverted into its ‘natural’ channel. Today the basin is a hypersaline drain for agricultural waste water, so is a toxic mess, with an uncertain future. There is a substantial literature on the Salton Sea, which has documented key changes to its ecosystem (e.g. Barnum et al. 2002) and the difficulties of finding a solution to its management, which must deal with the toxic water and also toxic dust.

Conclusions. Maintaining terminal lakes is an important conservation goal in California because each has its own distinctive chemistry and biota. Conservation mainly involves keeping them from drying up by reducing diversions of inflowing water. This management also reduces the severity of toxic dust storms, created by dry lake beds, that ultimately generate human health problems. The future of these lakes is uncertain given the predicted increase in long droughts from global warming. It is important to consider that future now, following the lead of the adherents of Mono Lake.

Peter B. Moyle is a Distinguished Professor Emeritus at the University of California, Davis and is Associate Director of the Center for Watershed Sciences.

Further Reading:

Barnum, D.A., Elder, J.F., Stephens, D. and Friend, M. eds., 2002. The Salton Sea. Hydrobiologia 473 (1-3):1-306.

Hart, J. 1996. Storm over Mono: The Mono Lake Battle and the California Water Future. Berkeley: University of California Press.

Lund, J. 2023. Tulare Basin and Lake – 2023 and their future, California WaterBlog, May 7, 2023

Moyle, P.B. 2023. Lake Tulare (and its fishes) shall rise again, California WaterBlog, April 16, 2023

Moyle, P.B. 1992, Biology and status of fishes of Goose Lake, California and Oregon. Unpublished report, written for the Goose Lake Fishes Working Group.

Moyle, P. B., T. Kennedy, D. Kuda, L. Martin, and G. Grant. 1991. Fishes of Bly Tunnel, Lassen County, California. Great Basin Naturalist 51:267-270.

Scheerer, P.D., Gunckel, S.L., Heck, M.P. and S.E. Jacobs. 2010. Status and Distribution of Native Fishes in the Goose Lake Basin, Oregon. Northwestern Naturalist 91(3):271-287.