Project Scope:
The American Samoa Power Authority (ASPA),
a quasi-public utility agency, is responsible for the
management, operation, and maintenance of American Samoa’s
water, wastewater, power and solid waste systems. In order to
secure U.S. funds for various water system improvements, the
ASPA Water Division is required to periodically prepare a water
facilities plan and related environmental assessment for the
U.S. Environmental Protection Agency (USEPA), Region 9. In view
of PPC’s extensive experience in American Samoa, PPC was
retained to prepare an environmental assessment of ASPA’s water
facilities plan for the 2001-2015 period.
The proposed water facilities
plan program included 14 water system projects. New
transmission line, water storage, and distribution system
projects were identified for the extension of the primary water
system to several villages relying on surface water systems for
their potable water supply. The development of new satellite
water systems was recommended for the remote village of Afono
since connection to the primary system was not feasible.
Proposed groundwater well development projects were also
identified for the Island of Tau where salt-water intrusion had
impacted the quality of existing groundwater well supplies.
System management projects reflected ASPA’s desire:
- to perform periodic
hydraulic modeling of its primary water system.
- the application of SCADA
systems to monitor wells, storage tanks, and transmission
systems.
- to establish operation and
maintenance program for new water treatment plants.
Since the environmental
assessment was developed for ASPA’s overall water facilities
plan, PPC examined four general approaches to future water
system delivery. These options included:
- continued use of village
water systems that rely upon surface water supplies
- the construction of roof
catchment systems on buildings that cannot be feasibly
connected to the primary water system
- development of independent
satellite water systems for villages that cannot be feasibly
connected to the primary water system
- extension of primary water
system to villages that presently operate and maintain
village water systems.
The direct and indirect
consequences of the construction of groundwater production
wells, water storage tanks, as well as transmission mains and
distribution systems, were evaluated in terms of physical land
alterations, potential soil erosion, and sedimentation of local
streams. Specific mitigation measures were recommended for
project and cumulative impacts.
The impacts of increased water
demands, groundwater well production, and withdrawals from basal
aquifers were also analyzed. This analysis quantified
anticipated water production requirements and assessed the
sustainability of groundwater resources to support anticipated
groundwater production. Anticipated reductions in the
hydraulic capacity of the primary water system were also
examined. Future water storage needs were identified for 8
water districts. Specific mitigation measures were again
recommended for project and cumulative impacts |