Date of Award

2016

Document Type

Open Access Master's Report

Degree Name

Master of Science in Geology (MS)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

John S. Gierke

Committee Member 1

Luke J. Bowman

Committee Member 2

Kari B. Henquinet

Abstract

Increases in water demand and urban development in Calderas community over the past decade have led to questions about the hydrology, water quality, quantity and sustainable management of Calderas Lake micro-basin. However, studies on baseline hydrology are limited for rural communities located inside volcanic origin watersheds of Guatemala. The scope of this study was to characterize the hydrology and establish a method to: 1) quantify a water budget, and 2) qualify the water quality of a lacustrine system that supply water for about 17,000 inhabitants on the state limits or rural Guatemala City. Mean annual rainfall and temperature at the watershed from 2009-2015 was 1,688 mm and 20 ºC, respectively. A Thornthwaite monthly-based water balance model was tested on Calderas micro-basin using three different methods [Hamon, Blaney-Criddle, and Papadakis] for estimating lake evaporation within the water budget. These methods revealed that a small fraction (less than 5%) of evaporates from Caldera’s lake having small impacts as outflows of the system. A surplus up to 25% is estimated as net precipitation after establishing the relation between water inputs and outputs of Calderas micro-basin.

Partial chemistry sampling (n=39) at Calderas Lake community intakes revealed no significant changes over a 6-month period. Chemical concentrations on Calderas Lake fall within national and international permissible levels for human consumption. Mean concentration for partial chemistry on alkalinity, pH, phosphates, hardness, chloride, Na%, nitrate, ammonia, TDS, and conductivity were 189 mg/l, 8, 6 mg/l, 248 mg/l, 14 mg/l, 0.003 %, 0.1 mg/l, 0.1 mg/l, 217 mg/l, and 334 µS, respectively. Contrary to high values of CFU’s measured on 2 water samples from each intake, 1 sample from Calderas elementary school water storage and 1 from Amatitlán lake as biological reference for E. coli and total coliforms. Mean CFU’s for E. coli and total coliform were 4 and 9, respectively. According to local and international regulations, microbiological indicators exceed quality standards for human consumption. These results may have implications on watershed management practices and provide necessary baseline hydrologic, water quantity and water quality for Calderas micro-basin.

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