The Nevada Wildlife Federation (NvWF) supports efforts to try and save Walker Lake. Below is some information about Walker Lake from the Walker Lake Working Group, an NvWF affiliate.

What You Can Do to Help Save Walker Lake

Walker Lake, Nevada: Oasis in the Desert by Tom Myers
Reprinted with permission of the author and Wild Earth magazine, PO Box 455, Richmond VT, 05477.  Originally published in Wild Earth, Summer 1997 edition.

Flying west at 30,000 feet over the Great Basin, after passing the Great Salt Lake, a remnant of ancient Lake Bonneville, a San Francisco bound traveler notices several lakes lined up from north to south. Prior to crossing the Pacific crest on the Sierra Nevada and Cascade Mountains, there is Abert Lake in southern Oregon, Pyramid Lake in northwest Nevada, Walker Lake in western Nevada, and Mono Lake in eastern California. All are remnants of wetter times during the Pleistocene and all lie at the end of their tributary rivers. And all are subject to the whims of humans living upstream.

Walker Lake is the terminal lake of the Walker River watershed draining east off the Sierra Nevada mountains (see map in next section). It supports threatened fish and hundreds of thousands of migrating birds, including biannual visits by up to a fourteen hundred migrating Common Loons to and from unknown locations. It is one watershed north of Mono Lake which became infamous when the City of Los Angeles diverted much of its inflow to suburban lawns and golf courses causing water levels to drop and water chemistry and limnology to change.

Walker Lake has similar problems in that upstream diversions are causing water level decreases and salt content increases to levels lethal to the resident fish and invertebrates. While there was one villain in the Mono Lake story, the Walker watershed has hundreds of individual irrigators in five separate major upstream valleys. The solution to the problem of a disappearing Walker Lake is simple: obtain more water. Implementing that solution is as complex as the watershed. Quoting limnologist Dr. Alex Horne of California-Berkeley, Walker Lake is a "rare and endangered species of lake" of which only a "handful exists in all of North America and on earth". The unfolding story of Walker Lake provides a case study of complex water issues that will be repeated all over the western United States.

Paleogeography
From the east side of the Sierra Nevada mountains, the Walker River flows north and east through broad, rich alluvial valleys before turning south to terminate in Walker Lake, where there is no outlet except for evaporation. These valleys, including Antelope, Smith and Mason Valleys, support as much as 100,000 acres of alfalfa. As lake water evaporates, dissolved material remains behind and, because there is less water for the same amount of solids (salts), the concentration, expressed as total dissolved solids (TDS) increases.

Walker Lake is a remnant of the Pleistocene Lake Lahontan which covered much of central and northern Nevada (Grayson 1993). As the climate dried, Lake Lahontan receded and many closed valleys became isolated dry lake beds. However, the three major rivers draining east from the Sierra Nevada continued to support lakes and wetlands. More famous than Walker Lake is Pyramid Lake, the only habitat of the endangered Cui-ui fish, into which drains the Truckee River. The Carson Sink and Stillwater Wetlands, recognized as a world Biosphere Reserve, lie at the terminus of the Carson River.

The level of Walker Lake fluctuated greatly during the past 5000 years (Benson et al. 1991). Most of these fluctuations were due to evulsions of the river channel rather than climatic variability. For example, the Walker River may have diverged through the Adrienne Valley north to join the Carson River (King 1993) around 2100 BP. When this occurred, Walker Lake completely dried. This may have prevented the cui-ui fish from establishing because it can not survive in fluvial systems. This diversion and subsequent desiccation may have allowed Walker Lake to attain its current low levels of salinity because much of the salt blows from a dried lake bed. Prior the unnatural drying beginning in 1882, TDS would have been near 2600 mg/liter (Myers 1997) which compares with values in a natural Mono Lake exceeding 20,000 mg/liter.

Biodiversity
Because of the historic fluctuations, only three endemic fish species survived in Walker Lake. Most numerous is the Tui Chub (Gila bicolor), a subspecies of special concern of the American Fisheries Society. The Lahontan Cutthroat Trout (LCT) (Oncorhynchus clarki henshawi) occupies the top of the fish food chain. An adaptive species, adult LCT in lakes may reach lengths of several feet, while adult individuals in fluvial populations may be only six inches long. Because of Weber Reservoir just upstream from the lake on the Walker River Paiute Reservation, LCT have not successfully spawned since the 1930s. Although classified as Threatened under the federal Endangered Species Act, the Walker Lake population has no protection because it is maintained by artificial propagation. A third native species, the Tahoe Sucker (Catostomus tahoensis) is rare in Walker Lake because of a lack of spawning habitat. These fish have evolved high tolerances to adverse conditions.

Many birds use the lake as a migratory rest stop and feed on the fish, especially the Tui Chub. The region around the lake is so important that it has been nominated as a "U.S. Important Bird Area" by the American Bird Conservancy. Birders found almost 100 bird species within 15 miles of the center of the lake during the 1996 Christmas bird count.

The Problem
The water law of most western states is based on the principle of prior appropriation which basically means: "first in time, first in right". The first person to put water to a beneficial use owns the highest priority water right on a river. Each water right owner on a river system has a priority date equivalent to the first date the water was used. The oldest, or senior, rights on a river must be completely filled before younger, or junior, rights receive any water. This is true without regard to the value of the use to which the water is applied. Water must be used at the same location in perpetuity unless the owner applies for, and receives, a transfer in point or type of use. Other users may protest such a change if they feel they will be harmed. For example, a user may be harmed if his or her water right is actually the return flow from another’s use and the proposed change will eliminate that return flow. Return flow is the water that "returns" to a stream after being used and may be either on the surface or in the groundwater.

Some states have begun to require minimum flows on some rivers to preserve habitat. Some states merely allow their wildlife department to purchase water rights and "use" the water by allowing flow to remain in the stream. On streams with unappropriated water, states may choose not to grant rights if they will lower flows below a minimum. Nevada does not currently have any instream flow requirements.

Diversions primarily to irrigate alfalfa have caused the decreased flows. The river basin is federally adjudicated, which means that a federal district court certified the water rights. Water rights exist for about 130% of the normal river flow. The only rights dedicated to the lake are flood water rights, which basically means that the lake is legally entitled to all water that currently escapes the diversions.

Most of the water rights owners are organized into an irrigation district to improve their water management. The district also owns two reservoirs on the system to store spring runoff. Prior to development, most lake inflow occurred during spring runoff. The district’s reservoirs evaporate about 10,000 acre-ft/year and Weber Reservoir, owned by the Walker River Paiute Tribe just upstream from Walker Lake, evaporates 4000 acre-ft/year. (An acre-foot is a volume equal to one foot of depth spread over one acre.) Evaporation is a rather small proportion of Walker River flow compared to many other developed rivers in the West, but the reservoirs deplete the flow by allowing storage rights to supplement the surface water flow rights which allows additional acreage to be irrigated.

Beginning in the late 1950s, many irrigators developed supplemental groundwater wells to be used only when surface water flows are insufficient to meet their right. This is a form of water banking in that wintertime surface flows will make up groundwater deficits. Pumping has decreased the groundwater levels by tens of feet which decreases groundwater flow to the river in the Smith Valley and causes flow losses in the river in the Mason Valley. During high flow years in the early 1980s, a much smaller proportion of flow made it through the valleys to Walker Lake than during previous years because of the aquifer recharge.

The combination of overappropriation, reservoirs and groundwater pumping has led to decreased flows to Walker Lake. Flows reaching Walker Lake from its river have decreased by two-thirds, from 285,000 acre-ft/year to 90,000 acre-ft/year since 1882.  The lake level dropped 150 feet between 1882 and 1994 and the volume decreased from 9.1 to 1.9 million acre-ft. During an eight-year drought prior to 1994, no flow reached Walker Lake. TDS concentrations peaked at over 14000 mg/l which is almost lethal for LCT and Tui Chubs. If allowed to continue, most fish will die and most of the birds that feed on them will have to find a different resting and feeding location. In arid Nevada, free water surfaces are long ways apart; the different productivity of reservoirs makes them poor replacements. Fortunately, high flows returned in 1995 because of an extremely wet winter. As of this writing (March 1997) after three wet winters, the lake level is up eight feet. Nonetheless, with evaporation rates of four feet per year, a return to dry conditions for just a few years would cause ecosystem collapse.

Solutions
People working to save Walker Lake have one primary goal which will satisfy most other interests: reestablish spawning runs of Lahontan Cutthroat Trout.  This requires three things.  The lake must have sufficient water that TDS levels are low enough to allow natural growth and productivity. The river must flow into the lake during the spring of enough years to allow spawning runs. And either a fish ladder must be built on Weber Reservoir or the dam must be removed to allow spawning runs up the river. Even hatchery-spawned LCT feel the reproductive urge when flow reaches the lake. During high flows in 1996, trout moved upstream until stopped by the Weber Reservoir stilling basin.

The first two needs will probably be solved jointly. If water rights are obtained for the lake, they will likely be satisfied during the spring spawning run. But western water law has impediments to the transfer of water rights for environmental purposes.

Buying and transferring rights, or water marketing, is a solution but the irrigation district has promised to oppose transfers in court. Although it is difficult to imagine how others are hurt by allowing water to remain in the river, court battles are costly. Ongoing groundwater and water rights modeling studies are being performed to show the impacts of potential transfers and retirement of irrigated fields. Ironically, it is possible that irrigated acreage retirement could lower well levels and decrease return flow because irrigation is the primary source of groundwater recharge. As the groundwater table lowers, it will no longer slope as steeply toward the river and flow will return slower. Prior to the advent of irrigation in the 1860s, the river probably lost water to the groundwater.

Other alternatives include paying for irrigation efficiency improvements and transferring the saved water to the lake. This would require a change in state water law. No states have recognized the transfer of saved water, but the Bureau of Reclamation has considered it as part of its new (since there are no more dams to build) water management mission. Arguments over the amount of savings from structural improvements (such as lining ditches) will occur. Advantages to the ranchers are that they could continue growing the same quantity of crop and have an easier irrigation system to operate. The district holds out because they argue that saved water should go to irrigate additional acreage. This would mean the end of Walker Lake and its ecosystem.

Litigation is an alternative currently being pursued. Attorneys for Mineral County, where the lake is located, plan to argue that a "public trust" exists for water to reach Walker Lake. The public trust doctrine is a common law legal rule that the public has an interest in its natural resources such as lake levels and fisheries. This doctrine was used to save Mono Lake in California because the court recognized that the public had a right to a certain lake level and curtailed the diversions to Los Angeles. For Walker Lake, the doctrine could be used to argue for a public right to a lake level necessary for certain ecosystem functions such as LCT and Tui Chub productivity.

Saving the lake does not require stopping all diversions. The amount of water required depends on the final desired level. The current volume of 2.2 million acre-feet is one-fourth of what it would be without irrigation. Current inflow averages less than 90,000 acre-feet/year. This must be increased by 50% to at least 135,000 acre-feet/year to maintain a minimally productive level which could be accomplished by retiring about 20% of the irrigated acreage and enforcing existing groundwater pumping laws (Myers 1997). While the savings of retiring fields varies with location throughout the watershed, the 20% figure is based on a consumptive use of almost 200,000 acre-ft/year. Additional inflow would allow the lake to rise to more productive and more natural levels that would withstand future droughts.

Conclusion
Saving Walker Lake will require that the water rights structure of the Walker River basin be changed radically. It requires the transfer of existing surface water rights to the lake and the cessation or substantial curtailment of groundwater pumping. It can be done in ways beneficial to both humans and Nature, but it requires the political will to make hard choices regarding whether we will save an ecological treasure or allow it to die. We need to ask whether it is ethical to so totally use a resource that all else dependent on it must die. Problems in the Walker River watershed resonate throughout the West, where overappropriated rivers are diverted dry during low flow periods to the detriment of Nature and downstream economies. It is time to reconsider "first in time, first in right" water law by remembering that the first in time were the native fish and birds and other wildlife that have been using Walker water for millennia.

References

Benson, L.V., P.A. Meyers and R.J. Spencer, 1991. Change in the size of Walker Lake during the past 5000 years. Palaeogeography, Palaeoclimatology, Palaeoecology 81:189-214.

Grayson, D.K., 1993. The Desert’s Past: A Natural Prehistory of the Great Basin. Smithsonian Institution Press, Washington, D.C.

King, G., 1993. Later quaternary history of the lower Walker River and its implications for the Lahontan paleolake system. Physical Geography 14:81-96.

Myers, T., 1997. The Hydrology of the Walker River Basin as Related to Inflows to Walker Lake, 2nd Edition. Prepared for Public Resource Associates, Reno, NV

About the Author
Tom Myers is a hydrologist working with Public Resource Associates and the Walker Lake Working Group.  He may be reached at (702) 348-1759 or tom@black-rock.reno.nv.us. Donations to the Walker Lake Working Group are welcome and tax deductible and should be sent to P.O. Box 867, Hawthorne, NV 89415.  The author thanks Susan Lynn, Marge Sill and Wendy Kuntz for reviewing this document.