Water policy is very often its own language. Add years of increasingly complex legal proceedings, and the result often feels like word salad.
Here are key terms, players and concepts that come up in the U.S. Supreme Court lawsuit between Texas and New Mexico over groundwater pumping and Rio Grande water. Words and terms highlighted are important context to better understand the case.
The basics
The case is officially called Original No. 141 Texas v. New Mexico and Colorado. The “original” indicates that the U.S. Supreme Court is the only court where the case will be heard.
Attorneys for New Mexico, Colorado, Texas and the federal government will present oral arguments Wednesday, March 20, at 8 a.m. Mountain Time.
Arguments could last several hours. An opinion from the justices could be released in the summer, but an exact date is unknown.
In January 2023, a deal between Texas, New Mexico and Colorado which would settle the Supreme Court case became public. In July, the special master recommended the Supreme Court accept the plan over the federal government’s objections that the settlement was invalid.
Federal exceptions to a proposed deal are the subject of the oral arguments before the U.S. Supreme Court on Wednesday.
How much water does Colorado get from the Colorado River?
It varies. Each year, Colorado can use up to 51.75% of the river’s available water supply for the Upper Basin states. If the basin’s full allocation of 7.5 million acre-feet of water was put to use, Colorado would receive about 3.85 million acre-feet of water. >> MORE
The lawsuit centers on Rio Grande water between New Mexico and Texas. In a 2013 complaint, Texas alleged New Mexico groundwater pumping in southern New Mexico was taking water owed to Texas, and violating a legal agreement called the Rio Grande Compact.
The Rio Grande Compact, is a legally binding document between Colorado, New Mexico and Texas to share the water in the Rio Grande. The three states made the agreement in 1938, ending years of water rights disputes, and it was later ratified by Congress. The Rio Grande headwaters are high in the Colorado mountains, near Creede, and Colorado is a defendant in this case because it is a signatory to the compact, however Texas is only seeking relief from New Mexico.
As with all interstate conflicts, only the U.S. Supreme Court has jurisdiction to hear the case.
Hydrology
The Rio Grande offers water to more than 6 million people in the U.S and Mexico. More than 80% of its water is diverted to agriculture in the Upper Rio Grande, which stretches from its snowmelt-fed headwaters in the San Juan Mountains of Colorado to about 90 miles east of El Paso, Texas.
Water is often measured in acre-feet (how much water it takes to cover one acre of land, one foot deep).
The river has an extensive groundwater system reshaped from water and geologic forces over millions of years. Water from the river seeps into basins in permeable rocks and ancient cracks and “underflow” to adjacent groundwater basins. Some of the water in deep aquifers, such as the Hueco Bolson under El Paso, was filled in over millions of years.
Another important source is groundwater found right around the river called shallow alluvium. This seeps into the banks and just below the riverbed surface, and sometimes into adjacent channels. These are very dynamic, and change rapidly.
Water always flows downhill, even underground.
This interconnection between surface water and groundwater is the crux of the allegations in the case presented before the U.S. Supreme Court.
In its complaint, Texas alleged that groundwater pumping below Elephant Butte to the state line was removing water from the Rio Grande owed to Texas under legal agreements.
In an order in April 2020, Judge Master Michael Melloy, overseeing the case as special master, wrote: “In simple terms, this case is a dispute about where the waters of the Rio Grande have been going, where they should have been going, and where they should go in the future.”
The people
Texas, New Mexico, and Colorado are official parties in the lawsuit because they are signatories to the Rio Grande Compact. Even though the allegations are between Texas and New Mexico, Colorado is still a participant in the case due to agreements under the compact.
The federal government is represented by the U.S. Department of Justice.
The Supreme Court allowed the federal government to intervene in a unanimous 2018 decision. The federal government is representing agencies such as the Bureau of Reclamation, the International Boundary and Water Commission and Bureau of Indian Affairs.
“Friends of the court,” or amicus curiae, are groups who submit legal filings informing the court of their positions, or offering insight, but don’t have an official standing in the case.
This includes public entities such as the Elephant Butte Irrigation District,El Paso County Water Improvement District No. 1, New Mexico State University, cities of Las Cruces and El Paso, and the Albuquerque Bernalillo County Water Utility Authority. Also included are farming organizations such as the New Mexico Pecan Growers and Southern Rio Grande Diversified Crop Farmers Association.
8th Circuit Appeal Judge Michael Melloy is appointed as the special master in the case, a fact-finding judge who creates a record for the U.S. Supreme Court through reports.
Gregory Grimsal, a commercial attorney from New Orleans, Louisiana, was the first person appointed as the special master. He was abruptly discharged in April 2018. Melloy, a federal judge in Cedar Rapids, Iowa, was appointed.
The disputes
Texas’ accusation is that New Mexico violated the interstate compact.
The compact lays out how the states split water. It uses measurements at specific water gages to guide how much must be sent downstream. The compact requires Colorado to deliver a proportion of water each year to New Mexico at the state line. New Mexico is directed to deliver its proportion of water for Texas and Mexico into Elephant Butte Reservoir, about 120 miles from the borders.
That water is used to supply irrigation districts in New Mexico and Texas and give Mexico its share, outlined in a treaty called the 1906 Convention. Both are acknowledged in the compact.
The compact establishes a commission to enforce and monitor the agreement. The commission is made up of three voting members from the states and one non-voting member from the federal government. All compact disputes are heard at the U.S. Supreme Court.
The Rio Grande Compact allows for a certain amount of variance in the water delivery amounts, noted as debits and credits. Colorado cannot exceed 100,000 acre-feet in debit, and New Mexico is limited to 200,000 acre-feet.
To read more about the details of the case visit SourceNM.com