Spring 2022 ICG Meeting Agenda
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.
Spring 2022 Drought ICG Recommendation Letter to the Governor
2022 Weather Outlook
- Mark O’Malley, National Weather Service, Drought Monitoring Technical Committee Co-chair
Spring 2022 ICG Meeting Recording