Arizona's reservoirs are well below average for this time of year. A compilation by the CLIMAS group at the University of Arizona, with data from the National Water and Climate Center [right] shows water storage ranges from 2% to 97% at different Arizona reservoirs. The current storage totals 33,345 thousands of acre-feet, compared to a maximum storage capacity of 56,128 thousands of acre-feet, or 59% of capacity.
The CLIMAS post says
Most of the reservoirs in Arizona are well below their historical average. Combined storage in Lakes Mead and Powell decreased by more than 500,000 acre-feet in April but is still about 10 percent greater than it was one year ago as a result of the copious winter snow in 2010–2011. The projected water year inflow to Lake Powell is 5.57 million acre-feet (MAF). If this holds true, inflow will rank as the fourth lowest on record since the closure of the Glen Canyon Dam in 1963. Precipitation in coming months could increase or decrease actual inflow, with the likely range falling between 4.9 MAF (45 percent of average) and 6.5 MAF (60 percent of average).
The Salt River Basin system, which supplies water to Phoenix, decreased by about 25,600 acre-feet in April and is about 4 percent above average for this time of year (Figure 6). Storage in the San Carlos Reservoir is at about 2 percent of capacity and is at its lowest level for this time of year since at least 1997, reflecting very low precipitation in southeastern Arizona during two consecutive La Niña winters.
Portions of the information provided in this figure can be accessed at the NRCS website: