Date of Award

2018

Document Type

Open Access Master's Report

Degree Name

Master of Science in Environmental Engineering (MS)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Brian Barkdoll

Committee Member 1

David Watkins

Committee Member 2

Kari Henquinet

Abstract

In situations where groundwater supply shows vulnerability, improving water distribution network resiliency can be desirable. To do so, one water source can be linked with another to provide a redundant source.

On the South Pacific island of Ambae, the water demands of its residents routinely exceeded supply. Residents had traditionally used rainwater collection as their sole water supply source. In 2017, groundwater drilling operations created an alternative water supply at two community institutions, Ndui Ndui Health Center and Londua Junior Secondary School. One borehole went dry during pump testing; the feasibility of linking these two boreholes is investigated herein.

EPANET is used to simulate the existing two intermittent groundwater supply units. EPANET is a hydraulic modeling program used to study pressurized water distribution systems. Several configurations connecting the two boreholes and supplying villages along the direct path joining the two sources are modeled. In doing so, the nature of the systems shifted from an intermittent water supply (IWS) to continuous water supply (CWS), improving water availability to the local population. The cost of materials and ongoing energy usage to operate the systems is analyzed. It is found that the capital costs of system upgrades were similar between the different models and such upgrades could be feasible. However, the high ongoing cost of operating generators to power the systems is beyond an economic level likely to be sustained by the local population.

Despite the benefits of connecting the two boreholes and shifting from IWS to CWS, the cost of ongoing operation of such a system is prohibitive to the local population. Due to issues surrounding the currently prevalent ashfall, this study did not examine the feasibility of using solar power as an alternative, nor did it explore low cost methods to improving water quality of collected rainwater mixed with ash. Such studies might prove fruitful at a later time.

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