Monsoon 2024-Final Stats
The official 2024 Monsoon rainfall totals have been reported by the National Weather Service-Tucson. See Haywood Plot below.
Average Monsoon precipitation (June 15-September 30) for the 129-year period (1895-2024) is 5.7". Monsoon preciptation for 2024 was 5.8". Therefore, the 2024 Monsoon was normal.
Note: 5 wettest (green) and 5 driest (brown) Monsoon seasons and 2023 Monsoon (red).
Colorado River System Status
The current (10/7/24) total reservoir contents for the Colorado River System is 25.07 million acre feet (MAF) which is very close to the 25.21 MAF contents at the same time in 2023.
Lake Mead (33% full) and Lake Powell (39% full) are essentially the same levels as last reported on 9/11/24.
The United States Bureau of Reclamation (USBR) is still projecting the Colorado System will be in Tier 1 Shortage for 2025 and 2026.
CAGRD 2025 Plan of Operation
The Central Arizona Water Conservation District Board (CAWCD) Board approved the Central Arizona Groundwater Replenishment District (CARGD) 2025 Plan of Operation (Plan) on 10/11/24. The Plan of Operation is required to be updated every 10-years. Note: CAWD is the same entity that oversees the Central Arizona Project (CAP) which delivers Colorado River in Arizona.
Remember, Marana Water's approved Designated Assured Water Supply (DAWS) through 2034 is 15,353 AFY. Of that amount, 72% is proposed to come from CAGRD groundwater replenishment. So it is important that CAGRD has the long-term permanent water supplies available to be able to meet Marana Water's demands.
CAGRD's Annual Water Supply Portfolio (Plan) is shown in Table 4.1 below. The total annual volume is 77,141 AFY. You will note that many of these supplies are subject to "reduction under any shortage condition". For example, if those supplies are discounted by a 20% Colorado River cut, the annual volume becomes 64,602 AFY.
In this scenario, the discounted total supply (64,602 AFY) is less than the replenishment obligations starting in 2035. See Plan Table 3.3 below.
However, the Plan does include a list of potential future acquisition of water supplies that range (lower end) in total from 406,000 AFY to 467,000 AFY including desalinated ocean water (30,000 AFY). So it appears that if these supplies are actually long-term and permanent and come to fruition, there is plenty of proposed CARGD water supplies to meet future demand.
If you remove the desalination of ocean water, that leaves a range (lower end) of 376,000 AFY to 437,000 AFY. Still more than enough to meet replenishment obligation. This begs the question as to why Arizona is even spending money and time investigating desalination of ocean water?
The Plan also includes a Replenishment Reserve but this water should only be used for emergencies and for payback of historical overdraft.
The location of CAGRD replenishment facilities is a concern as the replenishment facilities must be located in the same spot as the demand and it is not clear in this report how that will be achieved and what that will cost.
Bottom Line: The Plan does impart a rosy picture for CAGRD but issues still remain including the long-term permanent status of the existing and proposed supplies, potential Colorado River System cuts, physical location of replenishment facilities and cost.