Your friendly reminder: don’t freak out when Lake Mead drops below surface elevation 1,075 in the next few days. We don’t have a Lower Colorado River Basin “shortage”* yet, and likely won’t have for a couple more years.
What counts is the August forecast of the January 1 level. Mead is forecast to drop below 1,075 this summer, but is almost certain, absent some sort of “water knife” attack to release water from the dam, to be back above 1,075 by August. Here’s the pertinent language from the 2007 Interim Surplus Guidelines (pdf):
In the development of the AOP, the Secretary shall use the August 24-Month Study projections for the following January 1 system storage and reservoir water surface elevations to determine the Lake Mead operation for the following Calendar Year….
In years when Lake Mead content is projected to be at or below elevation 1,075 feet and at or above 1,050 feet on January 1, a quantity of 7.167 maf shall be apportioned for consumptive use in the Lower Division States of which 2.48 maf shall be apportioned for use in Arizona and 287,000 af shall be apportioned for use in Nevada in accordance with the Arizona-Nevada Shortage Sharing Agreement dated February 9, 2007, and 4.4 maf shall be apportioned for use in California.
The June forecast (pdf) projects 1,083 on Jan. 1. That’ll could go up again in the next few months’ forecast reports because June has continued to be wet in the Upper Colorado River Basin. We’ve gone from a year that was projected to be below 50 percent to a possible “normal” (median) flow this year into Lake Powell. That’s 1.4 million acre feet above the June 1 forecast.
* I think I’m going to start putting scare quotes around the word “shortage” after a conversation with a smart friend who points out that the word implies some deviation from what ought to be. We need to get used to variability as the normal state of affairs in the Basin, which sometimes includes less water.