73%

83% River Water Supply Report

43% 66% System Contents: 21.84 MAF 3,700’ As of July 26, 2021 33%, 7.91 MAF 95% Mid-Elevation Reservoir Capacities (MAF) Release 3,575’ Reservoir Current Change* Maximum 1,220’ Current Elevation 63% Lake Mead 9.03 -0.13 25.90 35%, 9.02 MAF 3,554’ Lake Powell 7.91 - 0.45 24.30 Tier 1 Shortage 1,075’ 3.10 - 0.01 3.75 Current Elevation 1,068’ 0.25 0.00 0.34 Navajo Reservoir 1.07 - 0.05 1.70 0.35 - 0.04 0.83 0.11 0.00 0.12 Crystal Reservoir 0.02 0.00 0.03

* With respect to previous month’s report Powell Unregulated Inflow 2021 • WY 2021 projected to be 2nd lowest inflow • 3.25 MAF – WY 2021 • April – July inflow forecast projected to be 25% of 30-year average • July inflow projected to be 104 kaf, 10% of the 30-year average • WY 2021 projected to be 30% of 30-year average

2 | Powell End of Month Elevations

• July 2021 24-Month Study

• In WY 2021, release is 8.23 MAF for min, most, and max probable scenarios

• In WY 2022, release is 7.48 MAF for min, most, and max probable scenarios

3 | Mead End of Month Elevations

• July 2021 24-Month Study

4 | Probability of System Conditions - June 2021 (Observed, Stress Test) 2021 2022 2023 2024 2025 Lake Powell Release > 8.23 MAF 0 0 0 0 28 16 47 33 55 37 Equalization > 8.23 MAF 0 0 0 0 3 0 9 <1 14 4 Upper Elevation > 8.23 MAF 0 0 0 0 25 16 38 33 41 33

Lake Powell Release = 8.23 MAF 100 100 0 0 0 0 1 0 8 8 Equalization = 8.23 MAF 0 0 0 0 0 0 0 0 0 0 Upper Elevation = 8.23 MAF 100 100 0 0 <1 <1 1 <1 5 <1 Mid-Elevation = 8.23 MAF 0 0 0 0 0 0 <1 <1 3 8

Lake Powell Release < 8.23 MAF 0 0 91 91 55 72 37 48 23 33 Upper Elevation < 8.23 MAF 0 0 0 0 <1 0 <1 0 0 0 Mid-Elevation = 7.48 MAF 0 0 91 91 55 72 37 48 23 33

Lake Mead Elevation Reduction Tiers 100 100 >99 >99 100 99 97 100 91 98 DCP Tier 0 (1090'-1075') 100 100 0 0 3 5 9 3 9 <1 Tier 1 Shortage (1075'-1050') 0 0 >99 >99 74 60 31 30 23 28 Tier 2 Shortage (1050'-1025') 0 0 0 0 23 34 54 65 39 32 Tier 3 Shortage (< 1025') 0 0 0 0 0 0 3 2 20 38 Source: U.S. Bureau of Reclamation Observed Record: 1906-2018 Stress Test Period: 1988-2018 Upper Basin Drought Response Operations Flaming Gorge 125 kaf Agreement (DROA) • Implementation of drought response actions triggered due to Lake Powell elevation projected to be at or below 3,525’ in July 24 Month Study

Crystal Reservoir • Drought response actions taken to minimize risk of Aspinall Lake Powell dropping below 3,490’ (minimum 36 kaf power pool)

• Additional releases from these Storage Project Act (CRSPA) reservoirs • Releases between July and December 2021 Navajo Reservoir • Total additional releases = 181 kaf 20 kaf

• Lake Powell elevation expected to increase by 3’ due to these actions Lower Basin Drought Contingency Plan – Additional Consultation Exhibit 1 to the Lower Basin Drought Contingency Plan Agreement, Sec. V. B. 2, states in part: • “…commitment to individual and collective action to avoid and protect against the potential for elevations in Lake Mead to decline to elevations below 1,020’”

• “…If any 24-Month Study for the minimum probable inflows projects that Lake Mead will be at or below 1,030’ anytime within the succeeding two Years, the Secretary and Lower Division States shall consult and determine what additional measures will be taken”

• Current modeling shows the possibility of Mead <1,030’ could be observed in the 24-Month study results in late 2021 or early 2022.