Sustainability and Social Justice

Date

5-2026

Document Type

Thesis

Degree Name

Master of Science in Environmental Science and Policy (ES&P)

Department

Sustainability and Social Justice

Chief Instructor

Timothy Downs

Second Reader

Eman Lasheen

Keywords

Water quality, climate change, land use/cover change, microbial indicators, Mexico.

Abstract

The Valle de Bravo Reservoir is a key surface-water component of the Cutzamala Aqueduct System, which supplies about 20-25% of the Mexico City Metropolitan Area’s (MCMA) water supply. This study provides data on the current (2025) water quality of the reservoir and compares them with data from 2004, including climate variability, water flow direction, water depth and volume change, land use/cover change, population growth, and urban development. Water samples were taken during two seasons (rainy vs dry) to evaluate physicochemical and microbiological parameters. Our key findings reveal seasonal differences in the water quality profile for both 2004 and 2025, as well as differences between seasons. The dry season predominated across most parameters evaluated. The Tizates point emerged as a persistent contamination hotspot for both years, recording the highest concentrations of fecal coliforms (FC), E. coli, Vibrio spp., as well as elevated conductivity, total dissolved solids (TDS), total nitrogen (TN), and total phosphorus (TP). A distinct spatial distribution of nutrient loads was identified across the reservoir. The southern points showed higher concentrations of total nitrogen during the rainy season due to urban runoff from Valle de Bravo and Avandaro, while the northern part of the reservoir exhibited elevated nutrient concentrations during the dry season linked to irrigated agriculture and nutrient contributions from the Amanalco River. Key drivers influencing water quality were identified, including runoff processes driving and mobilizing nutrients and pathogens, as well as sewage and wastewater and urban waste disposal. These findings are significant because documenting how water quality has changed over two decades provides essential evidence for adaptative management and mitigation.

Worcester

No

Available for download on Thursday, April 15, 2027

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