By Philip Reed

Photos by Alex Stephens

With the onset of summer, many states in WAPA’s footprint are facing the very real threat of drought so severe that it may complicate hydropower delivery. The circumstances behind this situation are beyond the ability of any one person or organization to control, but WAPA is at least able to prepare in advance.

As of early June, the U.S. Drought Monitor classified 60% of the western U.S. as being under severe, extreme or exceptional drought. This comes after 2020 brought one of the driest and hottest summers in recorded history, with multiple historic heatwaves and an exceptionally devastating fire season.

The situation is compounded by the fact that this past winter was less wet than usual, with reduced snowpack and only around 25% to 50% of the normal amount of rain falling in many areas throughout the West.

The cycle is unfortunate, as dry summers can make the following seasons more difficult. Dry conditions come with warmer weather, allowing moisture to evaporate more easily and quickly from vegetation and soil. This in turn leads to drier conditions, which themselves provide abundant fuel for potential wildfires.

The effects are already being felt across WAPA’s service area.

“This isn’t only a Desert Southwest or Colorado River Storage Project issue,” said Acting Senior Vice President and DSW Regional Manager Jack Murray. “Sierra Nevada is also struggling with drought. Anywhere in our footprint experiencing drought faces the same challenges.”

For Murray, these continuing drought impacts are not recent revelations. He has been following drought conditions closely and has been studying the trends. He has also been aware of the media attention on the water levels of Lake Mead, and the fact that the Bureau of Reclamation will likely – if conditions do not significantly change – declare a shortage on the Colorado River for the first time in the lake’s history.

Depending upon the severity and length of the drought, this can result in a number of potential impacts. Everything from water users facing service interruptions to increased danger of wildfires, which in turn can endanger WAPA’s transmission system.

“Poor hydrology impacts WAPA’s customers and the power we market to them,” Murray summarized.

Glen Canyon in the crosshairs

Senior Vice President and Acting Rocky Mountain Regional Manager Tim Vigil is keeping a close eye on – among other things – Lake Powell in Arizona and Utah.

The subject of much press attention, Lake Powell serves as a notable indication of the severity of the drought. As of July 1, Lake Powell has only received 30% of its normal amount of inflow for the water year. The lake is projected to be at 27% of capacity by September.

“That would be the lowest level since 1965,” Vigil said. “And, to put that in perspective, that was when Lake Powell was being filled. The capacity at that time was increasing. This time, if we hit 27%, it will be because things are moving in the opposite direction.”

Vigil went on to explain that a 24-month study performed in May showed that the most-probable forecast saw Lake Powell dropping to an elevation of 3,525 feet – 35 feet above the minimum power pool of 3,490 – in February 2022.

That elevation is significant, and it prompts a number of additional actions.

“It involves changing operations at Glen Canyon,” said Vigil. “It involves physically moving water from Blue Mesa, Flaming Gorge and Navajo into Lake Powell. It is an emergency action by Secretary of the Interior Deb Haaland. The Upper Colorado River Commission and Upper Basin states are preparing for the worst-case scenario.”

On July 16, Reclamation announced that it was releasing an additional 181,000 acre-feet of water from dams higher up on the Colorado River and its tributaries due to the imminent need to protect Lake Powell elevations from dropping below 3,525 feet.

Glen Canyon Dam provides around 75% of firm electric service for CRSP customers.

“Right now, purchase power for firming is overwhelming the CRSP revolving fund, known as the Basin Fund,” explained Vigil. “At this rate, it will reach an unsustainable level in October, and we will need to cut allocation or impose surcharge on customers for purchase power.”

He went on to explain that, if the situation is not addressed, there could be an increase of as much as $10 per megawatt-hour if no changes are made, which would represent a rate increase of nearly 40%. 

In order to mitigate the impacts of drought and to minimize large rate increases, CRSP MC is currently in a public process to revise its power rates to remove purchase power expenses. The proposed rate will give customers additional flexibility; each customer will receive a proportion of the actual hydropower generated and can also request to receive additional firming energy on a monthly pass-through-cost basis.

This rate is proposed to be effective Dec. 1 for a two-year period, allowing for the improvement of water conditions and the development of additional strategies.

Driest in decades

In SN, the Central Valley Project is experiencing its driest water year since 1977.

“This means that many water contractors to the CVP will get little or no water from the project this year,” said Supervisory Public Utilities Specialist Robert Delizo. “Due to the drought conditions, Reclamation decided to implement a warm water bypass in Shasta in April and May to preserve cold water until later in the year, when it is needed most for the spawning of the fish. This bypass had an estimated financial impact to CVP power customers of up to $7 million for replacement purchase power.”

Shasta Reservoir, Folsom Reservoir and New Melones Reservoir are the primary reservoirs affecting CVP generation. In April, it became clear that expected reservoir inflow from snowmelt failed to occur, leaving Shasta and Folsom reservoirs with lower than average capacity: 44% at Shasta and Folsom at 37%. Both are expected to drop further, potentially affecting municipal customers.

New Melones reservoir fares better at 57% capacity, thanks to storage accumulated during prior wet years.

“Low water levels in reservoirs during drought conditions reduce the energy that can be generated by hydroelectric dams,” Delizo explained. “With reduced generation output from the CVP, we expect reduced base resource will be available to power customers. This results in several financial impacts to customers.”

Purchasing power at a higher cost to replace what would otherwise be available from CVP is one obvious impact. Customers will receive fewer hydropower carbon credits, due to reduced CVP generation. The decrease in generation also means that less revenue can be used to reduce the Power Revenue Requirement.

SN and Reclamation will continue to work together to schedule generation.

“In view of the drought, Reclamation and the California Department of Water Resources prepared a Drought Contingency Plan to coordinate water operations,” said Delizo.

To keep power customers informed, WAPA and Reclamation held a joint-agency meeting with power customers in May to discuss conditions. WAPA and Reclamation are also meeting with customers at least quarterly to discuss water and power operations updates, Base Resource forecasts and power marketing updates.

Two projects to juggle

Murray is similarly keeping an eye on developments, specifically in terms of the two projects from which DSW markets hydropower: Boulder Canyon and Parker-Davis.

The Boulder Canyon Project markets hydropower from the Hoover Dam, with all generated output sold to customers on a pro-rata basis to align with available capacity, which itself is dependent upon the elevation of Lake Mead.

At customers’ request, WAPA is able to purchase energy to make up for any shortfalls in the output of Hoover Dam, with the cost of the purchase being passed along to customers. As Murray says, however, this is not an option that customers have historically exercised.

With severe drought, however, this could end up being necessary. “Every megawatt not generated by the dam is a megawatt that must be purchased from another source to meet customer needs, usually at a higher cost,” he explained.

The Parker-Davis Project, on the other hand, is a firm product.

“That means that we are contracted to provide a specific amount of power,” said Murray. “When there are shortfalls, WAPA purchases additional power.”

He went on to explain that Parker-Davis Project generation is dependent upon water orders from users downstream of the Hoover, Parker and Davis dams, many of whom use the water for agricultural purposes. The effect could snowball.

“Reduced deliveries due to a shortage declaration could further decrease generation, requiring even more purchased power expenses for customers,” he said.

In short, reduced generation causes an increase in purchased power costs as well as increases in power rates.

“Continued drought increases the cost of power on the market,” Murray emphasized. “Customers are pinched on all sides with increased costs.”

WAPA is engaging in conversations with customers and Reclamation to discuss options for mitigating potential financial impacts.

Note: Reed is a public affairs specialist.

Lake Mead during drought in 2015

This photo from 2015 shows Lake Mead’s elevation at 1,075 feet above sea level. Attention is once again on the lake during a very dry 2021.

Lake Mead from Hoover Dam in 2018

This 2018 view from the crest of Hoover Dam shows Lake Mead at an elevation of about 1,088 feet above sea level. This year, the Bureau of Reclamation may declare a shortage for the first time in the lake’s history.

Last modified on September 12th, 2023