August 2022 eNews

NMSU PhD Candidate Awarded Student Water Research Grant for Work Characterizing Key Components of the Rio Grande Compact and Rio Grande Project

NMSU PhD Candidate Awarded Student Water Research Grant for Work Characterizing Key Components of the Rio Grande Compact and Rio Grande Project

by Marcus Gay, NM WRRI Sr. Student Program Coordinator

The current water debate between New Mexico and Texas is complex. A PhD candidate at New Mexico State University, Claudia Trueblood, is researching three important topics related to this issue: (1) water supply of the Rio Grande Project (RGP), (2) Diversion Ratio provision, and (3) D2 allocation curve. NM WRRI has awarded Trueblood a Student Water Research Grant (SWRG) to assist with publishing this research in three separate peer-reviewed journal articles. The SWRG project is titled Statistical Characterization of Central Components of the Rio Grande Compact and Rio Grande Project.

The RGP is a federal Bureau of Reclamation irrigation project authorized by Congress in 1905 and largely completed in 1916. The RGP provides irrigation water to 90,640 acres in Elephant Butte Irrigation District (EBID) in New Mexico, 69,010 acres in El Paso County Water Improvement District No. 1 (EPCWID) in Texas, and up to 60,000 acre-feet of water per year to the country of Mexico. Elephant Butte Reservoir is the primary storage facility for the RGP. Caballo Reservoir was added in the late 1930s along with hydroelectric generation capacity at Elephant Butte Dam. Four primary RGP diversion points are in New Mexico, one is in Texas, and one diverts water to Mexico. Trueblood’s research aims to characterize the Rio Grande Compact’s annual credits and debits with water supply level and examine relationships among prior years’ annual credits and debits for the period 1940 to 2020.

The Diversion Ratio is the sum of annual RGP diversion charges to EBID, EPCWID, and Mexico to the annual release from Caballo Dam. It is used in the RGP allocation procedure as codified in the 2008 Operating Agreement among EBID, EPCWID, and the United States to adjust EBID’s annual allocation for losses in New Mexico due to groundwater capture. Trueblood’s second research objective is to develop a statistical model for forecasting the Rio Grande Project Diversion Ratio for an upcoming year based on pre-release groundwater levels, the current year’s estimated annual release from Caballo Reservoir, and the prior year’s release from Caballo Reservoir.

The third objective of Trueblood’s research attempts to reformulate the D2 equation, which is a linear regression that estimates total annual RGP diversions to EBID, EPCWID, and Mexico based on release and diversion data collected by Reclamation during the period 1951-1978, when the RGP was affected by persistent droughts. D2 serves as the basis for annual diversion allocations for EBID and EPCWID in the 2008 Operating Agreement.

Under the guidance of her faculty advisor, Dr. Phil King, and faculty sponsor Dr. Soyoung Jeon, Trueblood expects the results of her research to uncover potential autocorrelations between water available and water delivered by Colorado and New Mexico, to develop a method of estimating the seasonal Diversion Ratio during the irrigation season rather than only at the end of the season, and to improve on the estimation of the D2 allocation curve by including prior year release. This research has significant implications for allocating water and meeting delivery obligations downstream in Texas and Mexico.

Trueblood will present this research at the 67th Annual New Mexico Water Conference and is currently finishing the first manuscript of this project with her research committee. Trueblood, originally from Colombia, plans on graduating with her PhD in Water Science and Management next semester. After graduation, Trueblood plans to work in a job that directly relates to water management.