IGC Meeting Spring 2022
Drought Status Update & Monitoring Technical Committee Activities
The Lower Colorado River Basin (CRB) received below-average precipitation from October 2021 to March 2022, with the Gila and Verde River watersheds receiving 50-70% of average seasonal precipitation. For Water Year 2022 (WY2022), to date (October 1, 2021-April 25, 2022), most of Arizona received 50-70% of average precipitation, with eastern Coconino and central Navajo and Apache counties receiving 80-90% of average precipitation. During the first six months of WY2022, the state received 3.78 inches of precipitation (60% of average). Precipitation for Santa Cruz, Pima, Cochise, and La Paz counties ranked as some of the driest to date (period of record 1895-2022).
While the 2021 monsoon season significantly improved drought conditions in Arizona, drought expanded during winter and spring of 2021-22. As of April 28, 2022, 6% of the state was under Extreme (D3) drought, with 92% of the state experiencing either Moderate (D1) or Severe (D2) drought. While long-term drought maps showed some improvement near central Arizona counties, Standard Precipitation Evapotranspiration Index (SPEI) data demonstrated a continuation of long-term drought across the state.
Weather Outlook for Summer 2022 and Winter 2022-2023
According to trends over the past 30 years and modeling, odds favor a warmer than average summer in Arizona. There is a very slight increase in odds for a wet 2022 monsoon season, however, the randomness of thunderstorms will likely result in some communities not reaching average precipitation. A wet monsoon similar to 2021 would help improve soil moisture profiles, reduce water demand, and contribute to inflow/side flow into reservoirs. While it is too early to tell, El Niño Southern Oscillation (ENSO) models indicate that there is a 40-50% chance of La Niña persisting or redeveloping during Winter 2022-23, 35-45% chance of ENSO neutral, and about 10% chance of El Niño. There is a slight tilt in odds suggesting the potential for another dry winter in 2022-23 though likely contingent on La Niña conditions.
Colorado River Water Supply Update
As of April 25, 2022, the total CRB reservoir system supply was at 20.51 million acre-feet (MAF) or 34% of capacity, compared to 43% of capacity (25.68 MAF) last year. Lake Powell supply was at 5.77 MAF or 24% of capacity (3,522.51 feet) and Lake Mead was at 8.13 MAF or 31% of capacity (1,056.15 feet). According to the Colorado Basin River Forecast Center, as of May 3, 2022, snow water equivalent (SWE) above Lake Powell was at 54% of seasonal median. Despite the presence of good winter conditions towards the end of 2021, a steady decline has occurred, with the April forecast for unregulated inflow into Lake Powell falling to 4.1 MAF.
According to the Bureau of Reclamation (BOR) April 24-Month Study, Lake Powell is projected to end Calendar Year 2022 (CY2022) at 22% of capacity (3,515.05 feet), with a probable minimum of 3,504.04 feet and probable maximum of 3,547.32 feet. Similarly, the end of CY2023 is projected at 3,522.38 feet (24% of capacity), with a probable minimum of 3,494.17 feet and a probable maximum of 3,586.81 feet. BOR April modelling includes 350,000 AF held back in Lake Powell, however modelling still reflects the adjusted release pattern that would send this 350,000 AF to Lake Mead from June to September. Modelling does not reflect the future release of 500,000 AF from Flaming Gorge to Lake Powell. Measures to protect the elevation of both Lake Mead and Lake Powell are anticipated to be incorporated into future modelling. These measures are intended to protect water supply infrastructure, with benefits to hydropower being ancillary.
The April 24-Month Study for Lake Mead projects 29% of capacity (1,047.10 feet) at the end of CY2022, with a probable minimum of 1,045.01 feet and a probable maximum of 1,049.08 feet. Additionally, the end of CY2023 probable projection is 1,037.44 feet (26% of capacity), with a probable minimum of 1,017.07 feet and a probable maximum of 1,043.24 feet. These projections include some, but not all the 500+ plan activities, with system conservation agreements executed by all parties included in modelling. In April 24 month study, such agreements include approximately 232,000 AF with a remaining 67,000 AF to be included in the model as additional agreements are executed.
Salt River & Verde River Watersheds Water Supply Update
Summer 2021monsoon season and December precipitation and runoff helped to improve conditions at the start of 2022, but most of Winter 2022 (January-March) has remained dry with 39% of normal precipitation. WY2022 cumulative watershed precipitation was 7.03 inches (76% of normal) and the total reservoir inflow for January 1-March 31 was 155,000 AF (50% of median), with about 40,000 AF occurring in the first 5 days of January. March snowpack and runoff did favor some parts of the Mogollon Rim and led to a 6,000 AF increase in C.C. Cragin Reservoir. While Salt River Project (SRP) streamflow forecast for January-May 2022 was 205,000 AF (45% of median), reservoir storage remained fairly level during this winter runoff season.
As of April 26, 2022, the total SRP reservoir system was in good condition at 1,636,435 AF (71% of total storage capacity), despite two consecutive dry winters. Verde Reservoirs declined and Roosevelt Lake observed only a small increase in storage (+100,000 AF, 67% to 73%) over the winter. Roosevelt Lake is expected to decline throughout the peak water use summer months through late fall of 2022. Total SRP groundwater use for 2022 remains at 200,000 AF, and is expected to be between 200,000 to 250,000 AF in CY2023.
Impacts of Drought on Hydropower – Irrigation and Electrical Districts Association of Arizona
The Irrigation and Electrical Districts Association of Arizona advocates on behalf of agriculture with an emphasis on hydropower. Energy pricing patterns data shows how energy prices are highly dynamic and have nearly doubled since 2021, this may be further impacted by the loss of energy generation from rivers in Arizona. Hydropower generation is influenced by two major components: hydraulic head (difference between the upper and lower pools) and volume, both variables are impacted by dropping water levels and reduced streamflow.
The Colorado River Storage Project (CRSP) Act (1956) generates about 1,875 megawatts (MW), out of which Arizona gets approximately 10%. As Lake Powell water levels drop, so does the hydraulic head, leading to reduced efficiency of power generators. At 3,500 feet of water elevation, about 35% less energy is generated than when releasing the same volume of water at 3,700 feet elevation. The average cost of purchasing energy from a market, as opposed to paying for hydropower production (replacement power), fluctuates year to year. According to a 1971-2021 market price analysis, average CRSP replacement power cost roughly $63 million dollars in 2021, this is estimated to increase 33-68% in 2022. Based on the lost energy and cost of replacement power, the drought is costing federal power preference customers in Arizona more than $30 million above what they were paying a few years ago. The Boulder Canyon Project Act (1928) created Hoover Dam, which generates about 2,048 MW. Arizona receives about 20% of Hoover Dam energy and due to drought, there has been a 25% reduction in total energy generation. Glen Canyon Dam, Davis Dam, and Parker Dam have also experienced reduced energy generation. Supply chain issues have also impacted hydropower generation by increasing the cost of new capacity additions. Hoover Dam tourism revenue has decreased over the last three years due to drought. Additionally, demand of water supplies has shifted to groundwater, leading to greater energy demand.
Impacts of Drought on Hydropower – Western Area Power Administration
The Western Area Power Administration (WAPA) is a power marketing administration and wholesale electricity supplier under the United States Department of Energy. WAPA has over 17,000 miles of transmission lines and 700 customers throughout 15 states who, in turn, serve 40 million Americans. WAPA supplies power from Hoover Dam, Glen Canyon Dam, and Parker Dam. Parker-Davis Project Fiscal Year 2022 data and forecasts of energy supplied show a total estimate of 1,325 gigawatt hours (GWh) generated and 108 GWh of purchased replacement power (about 8%), this is due to a decline in water that can run through the system turbines. Price of replacement power purchases ($/MWh) is higher than sales price for customers and it is expected to increase through time. Average replacement power purchase price can be high and fluctuate depending on different weather phenomena or emergency events (up to $800/MWh) and the estimate certainty for price projections decreases as it is forecasted for longer term. On a system-wide scale, the estimated cost of drought impacts (2022-2030) for Hoover Dam is $939 million, and $42 million for Parker-Davis Project, when broken down, the highest cots are attributed to replacement power. Directly affected Arizona customers include power suppliers, as well as tribal, municipal, and agricultural stakeholders.
Impacts of Drought on the Navajo Nation
The Navajo Nation Department of Water Resources (NNDWR) monitoring efforts and data management processes were challenged by the COVID-19 pandemic, affecting drought condition data collection. NNDWR uses 85 active precipitation cans spread across routine routes on Navajo Nation, to monitor precipitation monthly. According to the National Aeronautics and Space Administration’s (NASA) Climate Engine Drought Severity Evaluation Tool (DSET) data from April 2021-22, all Navajo Nation agencies (Chinle, Crownpoint, Fort Defiance, Shiprock, and Tuba City) average Standard Precipitation Index (SPI) levels have not improved much due to the dry La Niña winter, which also affected streamflow. According to the U.S. Drought Monitor, as of April 26, 2022, northern Navajo County was in Extreme (D3) drought and most of Apache county was in Severe (D2) drought. Coconino County had a range of Abnormally Dry (D0) conditions, and Moderate (D1) and Severe drought, with a small portion at the northeastern corner in Extreme drought. Drought has impacted domestic water haulers, public drinking water systems, irrigators, dryland farmers and ranchers, wildlife, forestry, and recreation. June is the driest month of the year for Navajo Nation and impacts are expected to continue.
Impacts of Drought on the Gila River Indian Community
The Gila River Indian Community (GRIC) has been a major participant in water conservation efforts for the Lower CRB. While the community’s claims are to the Gila River and its tributaries, they have historically elected to take Central Arizona Project (CAP) water in lieu of their claim and are the largest entitlement holder of CAP water at 311,800 AF. The community’s Non-Indian Agricultural (NIA) water, at 120,600 AF, is most at-risk during drought. A Tier 1 Shortage unmitigated impact for this water would translate to a 70,000 AF reduction, and a complete loss of NIA water in case of a Tier 2 Shortage.
The GRIC currently only relies on about 20,000 to 40,000 AF for on-reservation demand, recently providing between 150,000 and 170,000 AF flex supply per year to Lake Mead conservation efforts. Previously, the community has used flex supply to recharge groundwater savings supply in the Phoenix and Pinal Active Management Areas (AMAs) but has shifted towards Lake Mead conservation efforts to ensure shortages remain below Tier 1. Total community contributions towards Lake Mead conservation since 2016 will reach 170,000 AF in 2022. By the end of 2023, the community plans to contribute 173,000 AF to Lake Mead conservation, including 62,000 AF of paid mitigation as part of the DCP, and an additional 111,000 AF in reductions. As part of the community’s plan to reduce its reliance on CAP water as much as possible, the GRIC has reduced some of its farming activity in 2022 to aid in their community water use reductions. Overall, the community is committed to strengthening drought resilience and maintaining the state at or below a Tier 1 Shortage in 2023, allowing continued water contributions and systems conservation.
The 2021 monsoon season helped improve short- and long-term drought conditions in Arizona. However, these conditions increased during the winter and spring (2021-22) due to La Niña. While the total SRP reservoir system is currently in good conditions, Lake Mead and Lake Powell have been steadily declining. The Drought Interagency Coordinating Group unanimously recommended that both drought declarations (PCA 99006) and (Executive Order 2007-10) be kept in place.
Drought Status Update & Monitoring Technical Committee Activities - Erin Saffell, State Climatologist, Drought Monitoring Technical Committee Co-chair
2022 Weather Outlook - Mark O’Malley, National Weather Service, Drought Monitoring Technical Committee Co-chair
Colorado River Water Supply Update - Rachel von Gnechten, Arizona Department of Water Resources
Salt River & Verde River Watersheds Water Supply Update - Stephen Flora, Salt River Project
Impacts of Drought on Hydropower-Irrigation and Electrical Districts Association of Arizona - Ed Gerak, Irrigation and Electrical Districts Association of Arizona
Impacts of Drought on Hydropower-Western Area Power Administration - Jack Murray, Western Area Power Administration
Impacts of Drought on Navajo Nation - Carlee McClellan, Navajo Nation Department of Water Resources
Impacts of Drought on the Gila River Indian Community - Jason Hauter, Akin Gump Strauss Hauer & Feld, LLP
IGC MEETING FALL 2022
Drought Status Update & Monitoring Technical Committee Activities
Water Year (WY; October 1-September 30) 2022 precipitation was below average at 11.39 inches (the average is 12.26 inches, period of record starting in1985). Since 1994, there have only been 9 years with a surplus of average precipitation. Statewide temperature for WY2022 was 62.2°F (average is 59.7°F). Temperature has been above average for 28 of the last 29 years, and it has increased by 0.5 degrees per decade since WY1994.
WY2022 started off dry after the 2021 monsoon season. While December was the wettest winter month for the state, April and May were the driest period on record for Arizona. October to May snow water equivalent (SWE) for the Lower Colorado River Basin (CRB) was 34% of the median (1991-2020 median), while the Upper CRB received above-average SWE (76% of median). Peak snowpack in the Upper CRB ended by the second week of April and it had above-average melting rates.
The 2022 monsoon season brought significant precipitation to Arizona and led to short-term drought improvements. The June to September 2022 period was the 9th wettest for Arizona on record, and the wettest for Cochise County. Moderate (D1) and Severe (D2) drought have remained across the state during WY2022. Due to the warm and dry spring, Extreme (D3) drought developed but diminished by the end of the water year. Short-term and long-term drought persisted throughout the western, northern, and southeastern counties. Overall, the state has experienced Moderate and Severe short-term drought almost continuously in the past 20 years. While long-term drought maps showed some improvement throughout central and southern Arizona, Standard Precipitation Evapotranspiration Index (SPEI) data demonstrated a continuation of long-term drought across the state.
Weather Outlook for Winter 2022-2023
The outlook for winter 2022-23 indicates weak to moderate La Niña conditions continuing into early 2023 (70% chance). With a few exceptions, historical La Niña episodes typically result in drier than normal conditions across Arizona. Odds are shifted towards a warmer than normal winter based on a combination of La Niña composites and trends over the past 10-20 years. Climate models and historical La Niña composites indicate a tilt in odds towards a drier than normal winter in Arizona. While soil moisture improvement in central Arizona may aid spring 2022-23 runoff, there is uncertainty about this improvement in the upper parts of the Colorado River Basin.
Colorado River Water Supply Update
WY2022 resulted in 6.08 million acre-feet (MAF) unregulated inflow into Lake Powell, which is 63% of average (9.60 MAF is the 30-year average). The WY2023 forecast for October projects an unregulated inflow of 8.10 MAF (84% of average) as the most probable, 4.80 MAF (50% of average) as the minimum probable, and 15.50 MAF (161% of average) as the maximum probable.
The Bureau of Reclamation’s (BOR) October 2022 24-Month Study projections show the Most Probable elevation at 3,522.63 feet (23% full) and Probable Minimum elevation at 3,522.59 feet for the end of CY2022. The end of CY2023 projections for Lake Powell indicate a Most Probable elevation of 3,523.87 feet (24% full) and a Probable Minimum elevation of 3,483.64 feet. For Lake Mead, the 24-Month Study projections for the end of CY2022 indicate a Most Probable elevation of 1,045.38 feet (28% full) and a Probable Minimum elevation of 1,045.15 feet. The end of CY2023 projections for Lake Mead indicate a Most Probable elevation of 1,026.18 feet (23% full) and a Minimum Probable elevation of 1,016.30 feet.
The U.S. Department of Interior (DOI) continues to work with Lower CRB states on developing voluntary measures and agreements, as well as with Upper CRB states to support their 5-point plan. Additionally, DOI is making investments in drought resilience and water management from the Bipartisan Infrastructure Law and Inflation Reduction Act. DOI issued a Notice of Intent to prepare a Supplemental Environmental Impact Statement (SEIS) to the 2007 Interim Guidelines to analyze at operational alternatives and potential additional actions to reduce deliveries from Glen Canyon Dam and Hoover Dam. The Notice of Intent was published in the Federal Register on November 17, 2022, and the scoping period is open through December 20, 2022. DOI does not currently have environmental coverage to release less than 7.0 MAF from Glen Canyon Dam or to adjust operational and shortage tiers.
Additional modeling was completed assuming the hydrology for WY2023 will be like that of WY2002. In order to protect the critical elevation of 3,490 feet at Lake Powell releases from Glen Canyon Dam must be reduced to 5.5 MAF. If no other water is conserved in the Lower Basin, this modeling scenario projects the end of CY2023 Lake Mead elevation at 991.40 feet.
Salt River & Verde River Watersheds Water Supply Update
As of November 1, 2022, reservoir levels were at a total of 63% of storage capacity (69% last year). The monsoon season (June 15–September 30) brought 144% of normal precipitation and 197,000 AF (210% of median) runoff from July-September into SRP reservoirs. August inflows for the Salt River were 3rd highest on record (twice the inflow received in August 2021), but Verde and Tonto inflows are about half. The wet monsoon season kept water in reservoirs, lessening the amount of storage level decline typically observed throughout the higher summer demand season. While the winter outlook is leaning toward a greater chance of drier weather, runoff, conditions are favorable heading into the winter if storms impact the watershed. SRP is predicting a planned groundwater use for 2023 to remain at 200,000 AF.
SRP hosted the Southwest Water Resiliency Conference in October. Scientists, politicians, business owners, and city water managers had the opportunity to get different perspectives on current conditions and climate projections. The conference was meant to highlight the differences of the CRB and the Salt and Verde basins.
Impacts of Drought on Hydropower – Irrigation and Electrical Districts Association of Arizona
IEDA monitors four main energy projects in the Colorado River: Boulder Canyon Project, the Colorado River Storage Project (CRSP), and Parker and Davis Dams. Arizona receives a 20% allocation from the power generated through Hoover Dam, through the Arizona Power Authority. At this project, there has been an over 20% energy decline since 2015. IEDA members represent about 80% of the energy delivered in Arizona. Through the CRSP (which includes 11 dams), Arizona receives about 18% of the power generated, this system has experienced a 15% reduction since last year. Glen Canyon Dam produces 80% of the energy generated by the CRSP system. Parker and Davis Dams have each experienced a 16% loss compared to average production.
Energy production can be calculated if we know how much water volume is pushed through the dams and what the water elevation is. Hydropower generation is influenced by two major components: hydraulic head (difference between the upper and lower pools) and volume, both variables are impacted by dropping water levels and reduced streamflow, therefore it is important to constantly monitor conditions. Lake Powell inflows were 58% of the 1991-2020 average (5.61 MAF) during WY2022.
For every kilowatt hour that does not get generated through hydropower, there is a need to purchase replacement power. Energy pricing has increased compared to last year (from up to about $160/megawatt hour to $210) because of increasing demand and decreasing energy supply. Summer 2022 costs surpassed projections (at least a 40% increase) for most IEDA clients, this is due to energy production supply constraints.
Hydropower impact unknowns include the following: what will be the impact of mitigation? what new mitigations will be proposed? will there be any legislative assistance offered? According to the Western Area Power Administration (WAPA), drought conditions have led to an increase of least a $40M/year energy cost for the total CRB customers. Total cost for Hoover Dam power is typically approximately $20M, this is similar for CRSP customers. In summary, the cost of replacement power for the energy lost, costs as much as the typical annual bill for Hoover and CRSP power.
2022 Wildfire Update
The outlook for the 2022 fire season showed increased potential for early fires caused by last year’s La Niña winter. Below average precipitation, drought, and unburned fuel carryover led to predictions of potential active fires in the southwest portion of Arizona. In April, that outlook expanded up through central Arizona. Increased fuel and dry grass across, and high winds in the desert created favorable conditions for fires to spread. The Tunnel Fire in Flagstaff and the Crooks fire in Prescott were uncommon fires in areas that wouldn’t usually burn in April. May saw above normal fire activity across southern Arizona, June saw increases across the state as predicted with extreme drought. July fire activity dropped due to monsoon season ramp up.
As of November 10, 2022, 1,347 fires, consuming 120,938 acres, burned. 2021 saw 1,760 fires and over 524,428 acres burned, while 2020 saw nearly 1 million acres burned. Bulk of activity occurred in southern Arizona as predicted by models.
The outlook for 2023 shows the potential of a winter fire season in southern Arizona. Upcoming La Niña may contribute to fire conditions, leading to an early start for fire season. What didn’t ignite this year could ignite next year as fine dry grasses could contribute to increased fires.
2021-2022 Forest Health Update
The Arizona DFFM partners with the U.S. Forest Service to conduct yearly surveys on dead and dying trees. They follow up with ground surveys to confirm findings. Drought and temperature impacts forest health and increases the likelihood of pathogens and insect infestations. Surveys are conducted between July through September.
There was a decrease in bark beetle caused mortality on Ponderosa pines in 2022, however mortality is still elevated. Pinyon has seen increased mortality across the state. There has been extensive tree mortality caused by drought, especially in northern Arizona. And there has been an increase in crown discoloration in Ponderosa pine forests. Continued Cypress and Juniper mortality due to drought. A large increase in the Mediterranean Pine Engraver (MPE) in the metro Phoenix area. The urban forest health conditions show very large increases in MPE outbreaks. The insect is especially attracted to stressed trees. Management options are being researched to control spread of these damaging insects.
Moisture improves forest health; the trees have better defenses from insects and diseases. La Niña winter means that drought stress could increase the damage in forests in the next year.
Impacts of Drought on Wildlife
While drought conditions in Arizona have slightly improved, thanks to the wetter than normal monsoon season, the state will still be contending with this drought for years to come. Three AGFD teams are focusing on mitigating the effects of drought conditions. The infrastructure team is renovating and updating water catchments with new remote sensing technologies to supplement water sources for wildlife. They are also increasing boating access throughout the state to counteract fluctuating water levels. The communications and marketing team are working to increase internal and public awareness of the impact drought has on wildlife, habitat, and recreation. They are also expanding public participation and pursuing funding to support drought mitigation. The biological team is continuing research on priority species and habitat to identify actions and monitoring metrics to minimize drought impacts, the team has also developed a strategic plan that will be available to the public in December.
AGFD has developed strategic plans to highlight drought responses for wildlife, developed numerous applications to report drought related issues, and have increased drought related messaging. AGFD has hauled over 2.5 million gallons of water to catchments between 2021 and 2022 and raised $347,000 in Fiscal Year 2022.
The 2022 monsoon season helped improve short-term drought conditions in Arizona. However, data shows a continuation of long-term drought across the state. While the total SRP reservoir system is currently in good conditions, Lake Mead and Lake Powell have been steadily declining. The Drought Interagency Coordinating Group unanimously recommended that both drought declarations (PCA 99006) and (Executive Order 2007-10) be kept in place.
- Drought Status Update & Monitoring Technical Committee Activities - Erin Saffell, State Climatologist, Drought Monitoring Technical Committee Co-chair
- Weather Outlook for Winter 2022-2023 - Mark O’Malley, National Weather Service, Drought Monitoring Technical Committee Co-chair
- Colorado River Water Supply Update - Rachel von Gnechten, Arizona Department of Water Resources
- Salt River & Verde River Watersheds Water Supply Update - Stephen Flora, Salt River Project
- Impacts of Drought on Hydropower-Irrigation and Electrical Districts Association of Arizona - Ed Gerak, Irrigation and Electrical Districts Association of Arizona
- 2022 Wildfire Update, Tiffany Davila, Arizona Department of Forestry & Fire Management
- 2021-2022 Forest Health Update, Viridiana Quiñonez Nevarez, Arizona Department of Forestry & Fire Management
- Impacts of Drought on Wildlife, Jade Dickens, Arizona Game & Fish Department