Here’s this week’s installment of the Colorado Water 2012 series from the Valley Courier. Craig Cotten (Division Engineer and Colorado’s Engineer Adviser to the Rio Grande Compact Commission) explains the Rio Grande River Compact:
The Rio Grande Compact is the agreement, signed in 1939, that provides for the equitable apportionment of the waters of the Rio Grande between Colorado, New Mexico, and Texas. During the late 1800’s and early 1900’s, much of the flow of the Rio Grande began to be diverted for irrigation in the upper part of the Rio Grande Basin, which caused concern to the downstream states. The Compact was necessary to fairly allocate the flows of the Rio Grande between the three states. It provides the framework for a fair allocation and use of water in the Rio Grande and its tributaries from year to year.
The delivery obligations set forth in the Compact were based upon a study of the Rio Grande during 1927 through 1936. Engineers studied the amount of water used by each state and developed a schedule of required delivery for Colorado and for New Mexico dependent on the total yearly flow in the river. The engineers also developed a limit on the yearly amount of water that Texas could use from the upper Rio Grande. These limitations allow each state to develop its water resources at will, subject only to its obligations as set forth in the Compact. In essence, the compact limits all three states’ use of water from the Rio Grande to approximately what they were using in the 1920’s.
The Compact requires Colorado to annually deliver a certain amount of water to the state line according to its delivery schedules. Colorado has a separate delivery schedule for the Rio Grande and for the Conejos River. Snowpack, rainfall, and the delivery schedules control the annual amount of water available to Colorado diverters. In any given year, from 20 to 60 percent of the water generated in the Rio Grande and Conejos River basins needs to flow to the downstream states. In a low water year, Colorado can use a higher percentage of the water, but in a high water year, Colorado must send a larger percentage to the downstream states.
It is important to note that Colorado does not have to strictly adhere to the Compact’s delivery schedules each year. The Compact allows for a system of credits and debits. This credit and debit accounting provision of the compact provides Colorado with some flexibility in managing water use from year to year.
Since 1939, the administration of the Rio Grande Compact in Colorado has been an evolutionary process marked by three distinct periods. The first period from 1939-1967 was a time when water rights were administered as they had been during the study period of 1927 to 1936. This administration worked well until 1952 when Colorado began to under-deliver on its obligations. By the mid 1960’s, Colorado’s debt to the downstream states exceeded 900,000 acre-feet. In 1966, the states of Texas and New Mexico sued Colorado in the U.S. Supreme Court to force Colorado to comply with the provisions of the Compact and to pay back the debt. In May of 1968, the Court granted a continuance of the case as long as Colorado met its Compact delivery obligation each and every year.
During the second period, from 1968 to 1985, Colorado administered the compact pursuant to that stipulation and was forced to begin curtailing water rights, i.e. shutting off ditches, specifically to meet the compact obligations. From approximately 1968 to the present, the Colorado State Engineer has directed that the Compact be administered as a two-river system (Rio Grande and Conejos) with each river responsible for its own delivery obligation. The State Engineer also directed that any curtailment of diversions would come from the junior water rights which would have otherwise been in priority on any given day of administration. Colorado met or exceeded its obligation each year from 1968 through 1984 because of the directive of the U.S. Supreme Court.
The third and current period began in June of 1985, when Elephant Butte Reservoir in Southern New Mexico spilled and eliminated Colorado’s remaining debt. The lawsuit against Colorado was dismissed, and since that time Colorado has operated in accordance with the Compact and has met or exceeded its obligation.
Although some believe that the compact causes too big of a burden to Colorado water users, it actually protects us and our water. Large cities downstream of us such as Albuquerque, El Paso, and Juarez are actively searching for more water. The downstream states also are always looking for more water to ease their endangered species, Indian water rights, and environmental issues. The compact offers a legal defense to these demands that Colorado send more water to quench the ever-growing thirst of the downstream states.
More Colorado Water 2012 coverage here.