There was deep tension in Cheyenne, Wyoming, in September 1947 as the negotiators for the Upper Colorado River Basin states gathered to try to hammer out a deal to divvy up their share of the Colorado’s water.

The 1922 Compact had split the river in two at Lee Ferry, and left for later the question of how to divide up the upper and lower divisions’ shares of the river among the respective regions’ states. By September 1947, the Upper Division states had been meeting off and on for more than a year, but progress was slow, stymied by a lack of the detailed water supply and use data some negotiators had hoped for.

Wyoming wanted to move quickly. As Eric Kuhn, my Utton Center colleague Rin Tara, and I write in a new paper:

Alluding to comments made by Utah’s Governor Maw earlier in the day, (federal commissioner Harry) Bashore suggested “the Commission attempt to negotiate this compact on the basis of percentage without attempting a lot of fine-haired calculations as to what the water is because it will change from year to year.” Adding that he was putting it to them plainly and “was not pulling any punches,” Bashore noted he would like “you folks on the Commission to do the same thing.”

Wyoming’s L. C. Bishop immediately responded that there was no need to wait for the report of the Engineering Committee. It was now time “to go ahead and negotiate the compact with the information we have.” He further noted that there are more lands than there is water, so it was time for the horse trading. Colorado’s Stone objected, noting “maybe in the end there will be an element of horse-trading in it, but Colorado feels we shouldn’t trade horses in the dark,” but added “there is an end and a limit to engineering studies and adding that there was much that could be done while the engineering work was being completed.”

The paper builds on Eric’s exhaustive review of the Upper Basin Compact negotiations, something which strangely we couldn’t find that any Colorado River Basin scholar had done in at the level of detail we felt was needed to understand the roots of today’s conflicts over questions still shrouded in ambiguity:

• How do we quantify consumptive use in the Colorado River Basin?
• How much water must the Upper Basin send down past Lee Ferry to users in the Lower Basin?

A Horse Named the Stream Depletion Theory

Stone’s argument against horse trading held for a time, and it was not until the marathon seventh negotiating meeting the following July that the horse trading finally began. The results have profound implications for modern Colorado River management.

To get to a final agreement, at the urging of Wyoming’s Wehrli, Bashore suggested the Commission break for a series of states only and state-to-state caucuses. It was also now time for Bashore to conduct some shuttle diplomacy. Stone, who up until this point had resisted any “horse trading,” realized he now needed to make some trades. He needed a horse named “The Stream Depletion Theory.” It appears that to get that horse, he gave Wyoming a horse named “A 14% Apportionment.”

The meaning of that language – “stream depletion theory” – is arcane, but the implications today are profound. Colorado pushed hard to argue that Upper Basin use should be measured not be diversions less return flows at each point along the river, but rather by the total impact of each state’s actions on the river’s flow at Lee Ferry. To win Wyoming’s backing, Stone offered Wyoming a juicy entitlement.

The result, eventually enshrined in the Upper Basin Compact, has profound effects on today’s arguments over Colorado River water.