Colorado’s Delph Carpenter joined with other members of the Colorado River Commission at the signing of the compact on this historical day. The signing took place in Santa Fe, New Mexico, with Secretary of Commerce Herbert Hoover presiding.
From CFWE’s Citizen’s Guide to Colorado’s Interstate Compacts, with a updated version now available for preorder:
Although subject to intense negotiation among the seven Colorado River Basin states, the compact, signed in 1922, is simple in concept. It apportions the right to consume water from the river and its tributaries between the upper basin states and the lower basin states. The dividing point between the two basins is at Lee Ferry, Arizona, eight miles below present-day Lake Powell.
The compact grants the states of each basin the right to use 7.5 million acre-feet of water per year “in perpetuity,” and gives the lower basin the right to increase its beneficial consumptive use of such waters by 1 million acre-feet per year from the Colorado River system. The compact also obligates the upper basin states to “not cause the flow of the river at Lee Ferry to be depleted’’ below 75 million acre-feet over any period of 10 consecutive years. To date, the obligation has always been met.
The compact did not affect water rights that existed at the time it was approved. If the cumulative flow at Lee Ferry is ever less than 75 million acre-feet over any 10-year period, the upper basin states would have to curtail the use of post-compact water rights until the Lee Ferry obligation is restored. The Colorado River’s flow has varied dramatically, from 3 million acre-feet to 24 million acre-feet annually. In wet years, the upper basin states can store more water than in dry years—regardless of the river’s flow, upper basin states send water downstream to satisfy the “non-depletion” requirement.
The 1922 Colorado River Compact is further explored and explained, with a current lens, in the new issue of Headwaters magazine, which is all about the Colorado River Basin. From the story “A Defining Moment on the Colorado River”:
The question of who gets how much water from the river is governed by the 1922 Colorado River Compact and 1948 Upper Colorado River Compact and a related set of laws, decrees and an international treaty collectively referred to as the “Law of the River.” It is within the bones of the original compact where part of the problem lies. The negotiators of the 1922 compact assumed the river could reliably deliver more than 17 million acre-feet of water each year, as measured at a point on the river 10 miles downstream of Lake Powell’s Glen Canyon Dam known as Lee Ferry, provided both Lake Mead and Lake Powell were constructed to store water in abundant years and even out low-flow water years. Gauge records from 1902, for example, showed there was only 9 million acre-feet available in the Colorado River that year, making storage necessary to implement the compact.
Rejecting some calls for a time-limited allocation, say for 50 years, the compact’s framers divided, in perpetuity, 15 million acre-feet equally between the upper and lower basin states, giving 7.5 million acre-feet to Arizona, California and Nevada, and 7.5 million acre-feet to the four smaller, less-developed upper basin states—Colorado, New Mexico, Utah and Wyoming. Another 1 million acre-feet was allocated to the lower basin, including flows from tributaries that enter the river below Lee Ferry. The idea was to ensure that the lower basin states, which then and now have the most senior water rights on the river, could not take unlimited amounts from the river simply because they were growing faster than the other states.
Skeptical of the deal even back then, Arizona would take more than 20 years to ratify the 1922 compact.
The compact may be 93 years old but still governs the way water is shared between the Colorado River Basin states, providing security for all basin states, though also leaving many questions about water allocation and scarcity open to interpretation.