Graduation Term

2022

Degree Name

Master of Science (MS)

Committee Chair

Wondwosen Seyoum

Abstract

Freshwater sources such as lakes, rivers, and reservoirs are essential part of water supply for irrigation, recreation, and most importantly, public and domestic water usage globally. Compared to groundwater that require costly facilities and infrastructure, freshwater source from reservoir can be treated efficiently and effectively to quickly meet public demand. In Indonesia, particularly, in the island of Java, there is a scarcity of freshwater source. There is less than 5% of available freshwater, which creates multiple water management issues such as water depletion during extensive pumping and dry period, and pollution of water due to high nutrient and wastewater input from high-density industrial and agricultural areas. Three major reservoirs in Java: Jatiluhur, Cirata, and Saguling are used primarily to support public, industrial, hydroelectric, and agricultural sector on Java Island. Considering high-density population in Java, these reservoirs are prone to water quality deterioration.

We implemented satellite remote sensing technique (e.g., Landsat 8), by taking advantage of specific information from satellite data such as spatial, temporal, and spectral information to estimate watercolor of the three reservoirs: Jatiluhur, Cirata, and Saguling as a proxy for water quality. We used chromaticity analysis, the CIE 1931 color space, to convert wavelength specific reflectance collected by the satellite into physiologically perceived colors in human color vision. First, random sampling locations were established within the boundaries of the surface areas of the reservoirs. Using these sampling locations, reflectance spectra information was extracted from the satellite data in time and space to address the following research questions: 1) what are the watercolor of the reservoirs based on spectral and spatial variation ?; 2) how the watercolor changes overtime? (2014-2021); and 3) what causes the change in watercolor of the reservoirs? (e.g., natural vs anthropogenic).

This study showed that in 2014, the Jatiluhur and Cirata reservoirs exhibited low to moderately disturbed water (blue to green and yellow watercolor), while the Saguling reservoir displayed relatively constant yellow and orange watercolor from 2014 to 2021. The change in the watercolor of the Jatiluhur and Cirata reservoirs maybe associated with the transport of nutrients, suspended sediments, and microorganisms from Saguling reservoir (i.e., natural causes) which is located upstream of the two reservoirs. On the other hand, the yellow and orange watercolor of the Saguling reservoir signifies anthropogenic inputs: public and industrial wastewater. Furthermore, this study demonstrated a new way of monitoring water quality of large water bodies using watercolor chromaticity analysis and satellite remote sensing data in regions where there is a scarce freshwater resource.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD2022.20221020070314044390.999970

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