Things are complicated. Here’s a timeline to help you keep track of the Supreme Court lawsuit New Mexico is facing on the Lower Rio Grande.

1902 – The United States Reclamation Service (now the US Bureau of Reclamation) is established to study and develop water resources in Western states.

1906 – The United States and Mexico sign a convention to ensure the Rio Grande’s waters are shared equitably between the two countries.

1906 – Construction begins on dams and canals on the Rio Grande. Leasburg Diversion Dam and Canal is completed in 1908, Elephant Butte Dam in 1916 and Caballo Dam in 1938. The Rio Grande Project, operated by the Bureau of Reclamation, provides irrigation water to farmers in southern New Mexico and Texas.

1938 – Colorado, New Mexico and Texas work out the Rio Grande Compact in a desire to “remove all causes of present and future controversy” among states and their citizens. The treaty was ratified by the three states and passed by Congress in 1939, and amended in 1948.

1950s – Drought strains water supplies along the Rio Grande. Farmers along the Rio Grande in Southern New Mexico and Texas drill about 1,000 new irrigation wells to supplement surface water supplies with groundwater.

2003 – After decades of relatively wet conditions, drought hits New Mexico, putting a strain on Rio Grande water supplies and reservoir levels.

2006-2007 – US Bureau of Reclamation creates a new operating procedure, which water users in southern New Mexico (Elephant Butte Irrigation District) and Texas (El Paso County Water Improvement District No. 1) sue over.

2008 – US Bureau of Reclamation, the Elephant Butte Irrigation District, and the El Paso County Water Improvement District No. 1 come to an agreement over water deliveries and sharing. The states of Texas and New Mexico are not a part of this new operating agreement for the Rio Grande Project.

2011 – Then-New Mexico Attorney General Gary King sues the US Bureau of Reclamation in New Mexico federal district court over the 2008 Operating Agreement, alleging that too much water was being given to Texas—water that should have stayed in New Mexico.

2013 – Texas sues New Mexico and Colorado in the US Supreme Court over violations of the compact. Texas alleges that by allowing farmers to pump groundwater connected to the Rio Grande, New Mexico has been taking more than its share of compact water. Texas wants the court to make New Mexico pay for the water it has been taking, over the course of many decades.

2014 – Special Master A Gregory Grimsal is appointed in the case and directed to submit reports to the court.

2014 – US Bureau of Reclamation intervenes in the case, alleging that by allowing farmers to draw water from the river and below ground, New Mexico is allowing people to use more water than they legally should. And it says New Mexico’s diversions interfere with water deliveries to Mexico.

2014 – New Mexico makes a motion to dismiss Texas’ complaint. (The court denies this in 2017.)

2015 – In a report to the New Mexico Legislature, scientists note that the Mesilla Valley aquifer “may no longer have the capacity to provide a reliable, supplemental supply during extended drought conditions and with the current levels of intensive use of groundwater.”

2016 – The special master releases his draft report, which indicates Texas has the upper hand in the lawsuit and recommends the high court reject New Mexico’s motion to dismiss.

September 2016 – US Bureau of Reclamation releases its final decision and environmental studies related to the 2008 Operating Agreement, which outlines operations through 2050.

January 2017 – New Mexico Office of the Attorney General, Office of the State Engineer and the Interstate Stream Commission announce they are working together on the case and also enter into joint defense agreements with New Mexico State University, PNM, the New Mexico Pecan Growers Association, Southern Rio Grande Diversified Crop Farmers Association, the City of Las Cruces and Camino Real Regional Utility Authority.

February 2017 – Special Master finalizes his first interim report. Parties have the chance to reply and/or file exceptions to his report.

January 2018 – Oral arguments occur in US Supreme Court. Justices hear from attorneys for Colorado, New Mexico, Texas and the federal government.

 This story was reported in partnership with the Santa Fe Reporter, New Mexico In Focus and KUNM-FM.