Many of us know the Truckee River’s largest source is Lake Tahoe and that the river flows to Pyramid Lake – Nevada’s largest natural lake. However, most who live and work in and around the Truckee Meadows have little idea how much water is taken out of the river before the water can make its way to Pyramid Lake. As we approach the end of the summer, river flow through Reno is diminishing, and upstream reservoirs hold water in large amounts following the heavy rain and snow from the winter of 2016-17 and the almost average year in 2017-18. The Reno-Sparks area – the Truckee Meadows and surrounding valleys – divert and use Truckee River water, of course. What isn’t obvious is where that water for residential and commercial and agricultural users actually goes. Is some of it returned to the river? How much water remains in the river after the water is diverted? Who treats the waste water and what happens to it? Let’s start with a big-picture understanding of who takes water out of the Truckee River in the Reno-Sparks area, how it is used, and how some of it is treated.
TMWA Municipal and Industrial Use
One of the larger diversions on the Truckee River is by the Truckee Meadows Water Authority (TMWA) which supplies municipal and industrial (M&I) water to nearly all of the Truckee Meadows. TMWA directly diverts water from the Truckee River at Chalk Bluff and at Glendale. Truckee River water also heads to Stead and Lemon Valley. Not all the water used for TMWA customers comes from the river directly, however. While most of the water TMWA distributes to its customers comes from the Truckee River, TMWA pumps water from wells or tributaries in the river’s watershed (like wells in Washoe Valley or the Callahan Ranch or tributaries like White’s Creek), or from wells located within the Truckee Meadows.
The Stead and Lemon Valley areas use local groundwater and imported groundwater pumped from Fish Springs Ranch wells 40 miles north along the Nevada/California border. This groundwater is “blended” with Truckee River water that was pumped uphill 500 ft in elevation to the Stead area.
A significant portion of the M&I water TMWA diverts from the Truckee River (and pumps from wells within the Truckee Meadows) is used for irrigating residential lawns and gardens, golf courses, and other landscapes throughout the region. With global warming (and some small amount of urban induced heating as well), the Truckee Meadows and the west in general is hotter than in the past requiring a longer irrigation season and more water to keep plants healthy during long hot spells and warmer days. The Truckee Meadows set a record already this summer with 19 days of 100º F or higher – and summer heat isn’t over yet.
Water that goes to outdoor irrigation is mostly consumed. That is, it is lost through evapotranspiration by grasses, plants, and trees and does not return to the river. A certain amount of water used outdoors runs off into the streets and gutters due to improper irrigation system maintenance or design or from car washing and other water applied to hard surfaces. This runoff water heads down the gutters and can pick up considerable contamination before returning to the River through the storm drain system.
As a result of the warming climate, landscapes require a longer irrigation season in the Truckee Meadows. The growing season now – defined as the number of days with non-freezing temperatures – has steadily increased since the 1950’s. Additionally, when daytime temperatures stay above 90º for weeks, vegetation often requires more water to remain healthy. And, it isn’t unusual to see sprinklers running even during November or March because of warm temperatures and lack of adequate precipitation. Ultimately, conserving water in our garden landscapes is essential in order to protect flows of the Truckee River and reduce the cost of supplying the region with water.
(The Truckee Meadows is mostly a high desert and receives only about 7″ of rainfall each year so most lawns, trees, and plants favored for landscapes wouldn’t survive without irrigation. Outdoor landscapes that use plants adapted to our dry climate save water and, when replacing lawns, can reduce yard maintenance as well.)
Agricultural Use also includes Parks and Public Spaces
There are diversions from the Truckee River into ditches built in the 19th and early 20th century by and for agricultural users in the Truckee Meadows (Steamboat, Coldron, Highland, Orr, Last Chance, Pioneer, Cochran, and Lake ditches.) The entire region was dominated by ranches then. After WWII change came to the ranch lands throughout the Truckee Meadows and, over the decades, urban and suburban development replaced the ranches. As most of the Truckee Meadows changed from ranches and farms to housing developments, the former agricultural water rights converted to M&I water rights now controlled by TMWA (previously by the Sierra Pacific Power Company). As the remaining agricultural land within the Truckee Meadows gradually disappears under housing, shopping malls, and roads, M&I usage controlled by TMWA will increasingly dominate.
Some Washoe County and Reno and Sparks City Parks and Golf Courses receive water directly from the ditches that originally supplied water to the ranches. For example, Rancho San Rafael receives water from the Highland Ditch which is supplied by a diversion from the river many miles away in Verdi.
Likewise, Virginia Lake Park receives water from the Cochran Ditch which is supplied by water diverted from the river in downtown Reno. Reno’s Paradise Park also receives water from area ditches, the Mountain View Cemetery receives water from the Highland Ditch, and the Orr Ditch supplies water for UNR’s Manzanita Lake. UNR’s Main Station Farm east of McCarran Blvd. receives water from the Pioneer ditch which diverts water from the river near the Grand Sierra Hotel-Casino. Water diverted from the Truckee River into ditches that isn’t consumed by the grasses, plants and trees flows through return canals, creeks, and sloughs and eventually returns to the river or enters the groundwater.
The Truckee Meadows still has a relatively high groundwater table especially in the eastern part of the valley. The high groundwater table reveals itself at the Sparks Marina Park.
This former gravel pit is now a large lake because groundwater “flows” into it continually filling it to the level of the groundwater table. However, in order to keep the lake from rising too high due to the high groundwater level (and causing problems for the surrounding houses and businesses), pumps remove water from the man-made lake to the nearby Truckee River.
Treated Waste Water Returns to the Truckee River
Most of the water used indoors by Truckee Meadows residences and businesses for cooking, cleaning, and sanitation (think toilets and showers here) goes via sewer pipes to the Truckee Meadows Regional Water Reclamation Facility (TMWRF) located on the east side of the valley at Vista where Steamboat Creek enters the Truckee River. After treatment at the TMWRF most of the water is released to the Truckee River (about 95% according to a 2005 report on waste water facilities in Washoe County.)
Some of the reclaimed water from TMWRF is used for irrigation of Golf Courses, the University Farm, certain parks and recreation facilities and other places where use of reclaimed water is deemed acceptable.
However, TMWRF is not the only waste water reclamation facility in the Truckee Meadows or the wider Washoe County. Waste water at Stead does not return to the Truckee River, but is released from treatment plants there that ends up in Swan Lake where it, along with normal precipitation, usually evaporates. Water for Swan Lake Nature Area provides habitat for the wetland park that rises and falls with the seasons and has thousands of birds using it including the area’s namesake Tundra Swans in the fall and winter. (In 2017-18, as the residents around Swan Lake and White Lake found out, there was so much water from natural runoff as well as imported groundwater that flooding was wide spread in low-lying areas as the closed basin filled with water. )
Likewise, water treated at the South Truckee Meadows Water Reclamation Facility (STMWRF) does not return to the Truckee River. The reclaimed water from this facility is stored in a reservoir and used for irrigation or evaporates from the reservoir. STMWRF treats waste water from residential areas south of Rattlesnake Mountain and up along the Mount Rose Highway. STMWRF’s reclaimed water is used for outdoor irrigation or evaporates from the reservoir used to store the treated water.
Only treated waste water from TMWRF is released to the Truckee River. Treated waste water from the other facilities, which is of lesser quality, is not be returned to the river or allowed to enter the groundwater.Treated waste water, therefore, can be either released to the Truckee River or used for irrigation of parks and other recreation facilities where the water is consumed by the grass, plants or trees through evapotranspiration. A completely separate piped distribution system is required to ship reclaimed water to sites for outdoor irrigation.
TMWRF treats water and has a capacity of nearly 40 million gallons per day (about 44,000 acre-feet per year maximum). The plant treats water to a fairly high standard and the facility also removes nitrogen and phosphorus in addition to contaminants. Nevertheless, the water released by TMWRF is higher in temperature and chemical pollutants than before it was used. Other treatment plants treat water to a lesser level.