Groundwater Banking as a Drought Prevention Measure in Reno, Nevada

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Proposal For a New Water Recycling and Groundwater Banking Facility in South Reno

Figure 1 – Water System Map

Background

Reno is the fourth largest city in the state of Nevada, with a population of approximately 250,000 people. It is located in Northern Nevada, in Washoe County, and parts of the city are located less than a mile from the California border. This proximity to California is an important aspect of the city’s water access, because the City of Reno relies on California to provide the majority of its water resources. The Truckee River, which begins in Tahoe City, California, is Reno’s main source of water. Additionally, the Truckee River is Lake Tahoe’s only outlet. Three reservoirs, all located in California, are also used to store water from snow melt. Water stored in these reservoirs is a key part of Reno’s water supply, especially during hot, dry summer months. Having available reserves of water is essential for the city, which lies in the rain shadow of the Sierra Nevada Mountains, and therefore receives very little precipitation year-round. When precipitation does fall, it is normally during the colder winter months as snow.

Figure 2

Reno’s location in the rain shadow plays an important role in the city’s climate, as well as the availability of water for the city. Additionally, Reno’s location on the Nevada-California border and the geography of the water system in the area have presented some unique challenges of water supply access in the past. Disputes over interstate water rights were largely resolved by the Truckee River Operation Agreement, which was signed in 2008 after a 26-year period of negotiations involving federal interventions. The agreement was implemented in 2015, and allocates 90% of Truckee River water to be used by Nevada, with the remaining 10% to California.

Figure 5 – Snowy Road in Reno

This agreement makes sense given differences in precipitation between the two states. In nearby Tahoe City, California precipitation is very high when compared with Reno’s average monthly precipitation. Most of the precipitation in the area actually falls as snow, which feeds into Lake Tahoe, and eventually flows out into the Truckee River as it melts. This is good news for the City of Reno, because their water source is receiving a large amount of precipitation even when the city itself is not. The average precipitation in Tahoe City in 2019 was 46.17 inches, as opposed to only 11.14 inches in Reno. It is important to note that Reno received an abnormally high amount of precipitation in 2019 compared with previous years. Additionally, precipitation typically falls mostly between November and March with the other months being very dry. Temperatures in Reno are consistently higher than in Tahoe City, however both locations see over 300 days of sun per year, leading to high rates of evaporation. The precipitation that does fall mainly falls as snow, which makes access to reservoirs a necessity during the summer months. It also means that the precipitation is not an immediately available water source for the city; as the snow slowly melts when temperatures rise, the snowmelt enters the water system becomes available to water users in the system.

Figures 3 & 4

Groundwater Resources

Groundwater is another essential component of the city’s water resources. The Truckee Meadows Water Authority (TMWA), Reno’s sole water utility provider, reports that groundwater sources and storage provide about 15% of their water supply. They also control 33 wells, which are used for the same purpose, to help supply water in the dry summer months or when the Truckee River has less reliable water supplies. Additionally, the protection of the source water from pollution is an important issue that the TMWA is currently working to resolve. There is an organization called Nevada’s Integrated Source Water Protection Program (ISWPP) which is responsible for protecting the source water from contamination so that it does not become problematic once it infiltrates the water table. Recently in the northern parts of the city, a moratorium on ground water pumping was called. This area of the city has seen an increase in residential developments within the past 10 years and government officials are unsure if the groundwater resources are adequate. This part of the city sits on top of the Cold Spring Valley aquifer, and it is estimated that current weather patterns replenish the aquifer annually, however with new added developments, overdrawing could quickly become an issue (Reno Gazette Journal). The main part of Reno, south of the North Valleys, does not sit on top of an aquifer.

Drinking Water Treatment

Because the City receives its water from The Truckee River as well as groundwater, water treatment is an essential component of the city’s water infrastructure. The Truckee Meadows Water Authority (TMWA) oversees all water utilities in the area. Chalk Bluff and Glendale are the two drinking water treatment plants managed by the TMWA. Chalk Bluff is the larger of the two treatment facilities, with the capacity to treat 90 million gallons of water a day. The Glendale facility is smaller, with the capacity to treat 37 million gallons of water a day. About 85-95% of the drinking water consumed in Washoe County is surface water from the Truckee River which runs from Lake Tahoe to Pyramid Lake. TMWA also manages 33 production wells, which according to their website “are used for summer peak times and provide off-river reliability. In winter months, the wells are used to recharge treated water.”

Wastewater Treatment

Figure 5 – Aerial View of the Reno-Stead Water Reclamation Facility

Reno’s sewage is currently treated at two treatment plants, the Reno-Stead Water Reclamation Facility, and the Truckee Meadows Water Reclamation Facility. The Reno-Stead Water Reclamation Facility is located to the north of downtown Reno and is operated by the city. After water is treated at the Reno-Stead Facility, some of the treated effluent is discharged into Swan Lake. The Truckee Meadows Water Reclamation Facility is located to the east of Reno and also treats waste water from the neighboring city of Sparks. This plant discharges treated water into the Truckee River, or to effluent reuse sites in both Reno and Sparks.

Reno’s Water Problems

Drought

Considering the existing water resources and infrastructure that Reno currently has, the city faces a number of unique water related challenges. The low amount of precipitation received, and its snowfall, make Reno a prime location for seasonal droughts, which occur most years and especially on years that see low precipitation during the winter months. Additionally, the city has seen large growth in the past few decades, both in terms of population and development. This increased urbanization and population growth has left Reno with the need for additional water infrastructure.

Figure 8 – Flooded Road In Reno
Flooding

While drought is a commonly considered problem in Reno, the city is also prone to flooding during storm events. More recently, in the Lemmon Valley area of Reno, a subdivision north of Reno, flooding around Swan Lake has been particularly bad due to excessive effluent discharge from the Reno-Stead Water Reclamation Facility. Swan Lake began flooding in 2017 following a heavy precipitation year. Flooding damage in 2017 affected roads, homes, a church, and a school. Besides precipitation, an important contributor to Swan Lake’s water levels and flooding problem is the Reno-Stead Water Reclamation Facility that actively pumps its effluence into Swan Lake. They have since struggled to move water out of the reservoir which currently does not have an outlet. The water can only leave through evaporation, which is not happening fast-enough to keep pace with the effluent entering the lake from the Reno-Stead facility.

Figure 9 – Flooding in Lemmon Valley

As of August 2019, there were plans to build a pipeline to pump water from the lake to nearby agricultural fields and golf courses, but this is a costly, and incomplete solution. Thinking beyond short term and considering the increase in effluent from the Reno-Stead facility as population grows in Reno, a more complete solution is needed to take pressure off of Swan Lake and the Reno-Stead Water Reclamation Facility in the long term.

Figure 10 – Flooding in Lemmon Valley

In May 2019, the Reno Planning Commission denied a proposal to expand the wastewater treatment capacity at the Reno-Stead facility. As of June 4, 2019, the City of Reno implemented a “Flow Shave Project” to divert some of the raw sewage from the Reno Stead facility to the Truckee Meadows facility. This project reduces some of the effluent going into Swan Lake and redirects it to the Truckee River, but is not a complete or long-term solution. Existing water reclamation facilities in Reno are already experiencing problems managing the inputs of wastewater, a problem that will only become worse as the city continues to grow. Southern Reno is an area that is notably underserved by the existing water treatment infrastructure, and is experiencing new growth and rapid development.

Proposed Solution

New Water Recycling Facility and Groundwater Banking


A proposed solution based on these unique water challenges in Reno is to build an additional treatment facility that would be constructed to accommodate water recycling and banking. This facility would be located in South Reno to help support growing development and populations in this part of the city. This proposal to build a new water treatment and recycling facility is based primarily on Reno’s susceptibility to drought conditions, inconsistent precipitation and surface water supply, and pressures of increasing urbanization placing additional strains on already limited water resources. Recent concerns about flooding in Lemmon Valley are also indirectly addressed through this proposal. The proposed water treatment facility will treat waste water to a standard that allows for it to be recycled for potable use. With advanced wastewater treatment facilities, effluent will be clean enough to be pumped back into the ground for aquifer recharge. This system of Indirect Potable Reuse (IPR) will allow for recycled water to contribute to drinking water supplies when surface water sources are low. By creating a system that pumps treated, potable recycled water back into the ground, this proposal will manage groundwater supplies in a sustainable way. Having a reliable and rechargeable groundwater supply to tap into is critical for Reno, where surface water and precipitation are often affected by drought conditions. Though TMWA has done smart planning to create a better storage system for surface water, groundwater supplies are an essential element of water security. Additionally, IPR is something that Reno and the surrounding region have already been seriously considering – feasibility studies were published in 2011 and 2019, though these studies never resulted in actionable plans to start using IPR despite Reno being a good candidate for the practice.

Figure 11 – Map of Current and Proposed Water Treatment Facilities in Reno

The proposal to build a water recycling and banking facility expands on existing plans by the TMWA to implement a new drinking water facility in South Reno. The new drinking water facility, Mt. Rose Water Treatment Plant, will treat surface water from Whites Creek to be used as drinking water when flows are adequately available. This new drinking water facility is being built out of concern for diminishing groundwater supplies due to well reliance in this area. Unfortunately, this new facility fails to address the need for expanded wastewater facilities to serve the Southern part of Reno and offset the burden placed on existing wastewater facilities. With the current infrastructure, all wastewater created by residents of Southern Reno will need to be treated at one of the existing plants, which are already overburdened, as evidenced by Swan Lake flooding. The underlying concern of groundwater depletion in South Reno cited as a reason for building the Mt. Rose facility is also not fully addressed or solved with the current proposal. Adding a water recycling and banking facility in South Reno would both offset the burden on existing facilities and help recharge groundwater supplies. It is clear that the introduction of Indirect Potable Reuse (IPR) is a smart strategy for Reno to use to provide better water security and maintain groundwater supplies.

Figure 12 – Rendering of Mt. Rose Plant
New Water Recycling Plant Location

The proposed location for the new water recycling and banking facility is in near the southernmost part of the city’s boundaries. This proposed location would be near the current location planned for the Mt. Rose drinking water treatment facility, which we acknowledge is unusual. However, the geography of the proposed site is located in the valley of Mt. Rose and is at the bottom of the water system for the city. With a growing number of housing developments in this part of the city, it makes sense to have additional drinking water and wastewater treatment to support the growing population. Proposals to expand and the existing water treatment facilities fall short, as evidenced by the failed proposal to expand the Reno-Stead facility in May 2019. Not only will building the new water reclamation facility in the South of Reno can take strain off of the existing water reclamation facilities in the northern part of the city, it will also provide a way to recharge strained groundwater supplies in the South through IPR. Expanded water treatment capacity will be extremely important as Reno’s population continues to grow. It will also hopefully decrease flooding risks in the north.

Limitations

While the proposal to add a new water recycling and groundwater banking facility provides many solutions for Reno, it is not a fix-all solution. Though water recycling and groundwater banking through IPR can make recycled water an accessible resource for drinking, this is not an added input to the system, but rather a way to recapture some of the existing inputs. Therefore, drought remains a concern for Reno despite the additional water security provided by a new facility. This solution is also not a green light for unchecked development in Reno. The city should still consider growth management and limited development practices, especially in areas not already served by existing infrastructure.

Funding

The proposal to build a new water recycling and groundwater banking facility of course comes with a hefty price tag for TMWA and the city of Reno. While this proposal is primarily focused on the existing water problems in Reno and explaining a solution to address them, it would be ignorant to not include at least provide a brief mention of the cost. Unfortunately, water infrastructure upgrades are by nature costly and therefore tend to be controversial. However, investing in a new water recycling and groundwater banking facility in South Reno will provide a solution to costly flooding problems and provide additional water security for a drought prone city. It is important to note that Washoe County has already spent over $7 million dollars on floodwater management focused on Lemmon Valley. The City of Reno is investing $3 million in a pipeline as a way to drain water from Swan Lake, and the county is investing $2.5 million for future improvements to Lemmon Valley. Not investing in water infrastructure is also expensive.

With this in mind, a way to offset costs of building a new water recycling and groundwater banking facility could be to change the existing water utility rate structure in Reno to generate additional funding for TMWA to invest in the new facility. A steeper pricing model would have the dual advantage of encouraging water conservation among consumers by making excessive water consumption more costly. In Reno, flat rate water pricing was phased out in 2015 by TMWA and replaced by and incremental borrowing rate (IBR) pricing model. Under the IBR model water is priced at a flat rate based on meter size, and users are subject to additional commodity charges (per 1,000 gallons), which increase slightly depending on water consumption brackets. This is absolutely a better pricing model than flat rate, and in theory should allow for basic water needs to be met affordably while encouraging large consumers to be more mindful and efficient of water use to keep their water bill down. However, while the IBR model is a good one, the actual pricing breakdown is not aggressive enough to decrease water use based on pricing alone. The tables below show the existing pricing structure for residential water service in Reno.

Revising the existing IBR pricing model can incentivize smarter water use among consumers, while also providing a way for TMWA to generate additional funding to invest in a new water recycling and groundwater banking facility. A possible approach includes restructuring the commodity charges to make large water consumers pay more for water. This could be done by adding more tiers with increasing fees, or simply raising the fees for the existing three tiers. The rate increases for big water consumers will incentivize water conservation while still generating a stable funding stream for TMWA to take on necessary maintenance of existing facilities and construction of the new wastewater treatment plant.

Conclusions

Like any city, Reno, Nevada has unique challenges with its water management and infrastructure systems. Though the Truckee Meadows Water Authority has done a good job of managing surface water supplies and delivering water utilities to Reno residents and businesses, there is room for improvement. Reno is prone to both drought and flooding conditions, and is a growing city with increased urbanization pressures putting strains on existing water treatment facilities and groundwater supplies. In order to mitigate these concerns, plan for a resilient future, and meet the water needs of a growing population, especially in southern Reno, building a new water recycling facility and groundwater banking system is a sensible and smart solution that will help to ensure a secure and clean water supply for years to come.

References

Your Water. (n.d.). Truckee Meadows Water Authority. Retrieved May 9, 2020, from https://tmwa.com/your-water/

Mt. Rose Water Treatment Plant at Whites Creek. (n.d.). Truckee Meadows Water Authority. Retrieved May 9, 2020, from https://tmwa.com/project/mt-rose-plant/

Spillman, B. (n.d.). Fixing Swan Lake ‘nightmare’ flooding in north Reno won’t be cheap or easy. Reno Gazette Journal. Retrieved May 9, 2020, from https://www.rgj.com/story/news/2019/04/29/fixing-nevadas-nightmare-flooding-wont-cheap-easy/3593564002/

Team, N. W. S. C. I. W. (n.d.). National Weather Service—Reno, NV. Retrieved May 9, 2020, from https://w2.weather.gov/climate/xmacis.php?wfo=rev

Water Rates. (n.d.). Truckee Meadows Water Authority. Retrieved May 9, 2020, from https://tmwa.com/tmwa-customers/water-rates/

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