Assessing Escherichia coli and Microbial Source Tracking Markers in the Rio Grande in the South Valley, Albuquerque, New Mexico, 2020–21

Scientific Investigations Report 2023-5019
Prepared in cooperation with Bernalillo County
By: , and 



The Rio Grande, in southern Albuquerque, New Mexico, is a Clean Water Act Section 303(d) Category 5 impaired reach for Escherichia coli (E. coli). The reach is 5 miles in length, extending from Tijeras Arroyo south to the Isleta Pueblo boundary. An evaluation of E. coli and microbial source tracking markers (human-, canine-, and waterfowl-specific sources) was conducted by the U.S. Geological Survey to determine the extent and source of fecal bacteria within the impaired reach of the Rio Grande, primarily during the dry season (November through June) in 2020 and 2021. Samples were collected in the river cross section at three locations within each site and collected during both the dry season and the wet season, thereby providing data over a range of flow conditions to better understand the extent and source of fecal bacteria. Because fecal microorganisms may readily attach to sediments, riverbed material samples were also collected. During the dry season, E. coli concentrations in water were primarily detected below the New Mexico Surface Water Quality Standard of 410 colony forming units per 100 milliliters and mostly human and canine sources were detected. However, approximately 40 percent of the water samples exceeded the Isleta Pueblo water quality standard of 88 colony forming units per 100 milliliters. E. coli concentrations in bed material were detected at low concentrations, and the bed material was a sandy substrate, with little fine-grained material, a suitable habitat that would allow for bacterial growth during the dry season. Significant spatial and temporal differences, where p-values were less than 0.05, were found in water-quality samples for E. coli (seasonal) and the human tracker concentrations (between sites and within a cross section of a site). Given the lack of correlation between discharge and E. coli concentration and the human marker being most prevalent in the study area, the sources of E. coli in the dry season are likely nonpoint sources. The results from this study will help decision makers determine the efficacy of their best management practices and guide new practices to improve water quality in the reach.

Suggested Citation

Travis, R.E., Wilkins, K.L., and Kephart, C.M., 2023, Assessing Escherichia coli and microbial source tracking markers in the Rio Grande in the South Valley, Albuquerque, New Mexico, 2020–21: U.S. Geological Survey Scientific Investigations Report 2023–5019, 48 p.,

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Data-Quality Assurance and Assessment
  • Characterization of Escherichia coli Microbial Source Tracking Markers and Other Parameters in Water and Bed Material
  • Summary
  • Acknowledgments
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Assessing Escherichia coli and microbial source tracking markers in the Rio Grande in the South Valley, Albuquerque, New Mexico, 2020–21
Series title Scientific Investigations Report
Series number 2023-5019
DOI 10.3133/sir20235019
Year Published 2023
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New Mexico Water Science Center
Description Report: viii, 48 p.; Data Release
Country United States
State New Mexico
City Albuquerque
Other Geospatial Rio Grande, South Valley
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details