Pedersen Planning Consultants
evaluated potential stormwater detention opportunities in six
watersheds on the Island of Tutuila, as well as land use
recommendations associated with future resource management.
Investigations were made in the following watershed planning
areas: Leone, Nuuuli, Tafuna, Pago Pago Bay, Vatia, and Tula
where historical flooding was common, significant coral
communities characterized the nearshore water environment, or
other stormwater issues were evident.
Existing and future stormwater
characteristics in each of the watersheds were evaluated using
TR-55 software. Hydrographs developed from application of the
software were used to determine the size and volume of potential
detention ponds that could be used to reduce flood potential and
downstream discharge of surface water and sediments into the
Conceptual site plans were
developed for selected sites in each watershed. Specific
stormwater management issues and opportunities were identified.
Proposals included the location and type of proposed detention
facilities, as well as improvements to existing stormwater
management facilities such as inlet structures, storm drains,
culverts, and drainage ditches. Order-of-magnitude costs were
developed for all new construction, repairs, as well as
long-term operation and maintenance.
Conceptual land use plans were
also prepared to facilitate discussions with traditional village
leaders concerning future land uses in the four watersheds.
Since communal land ownership is a significant part of the
Territory, PPC developed a creative, interactive process to help
influence future land use decisions by traditional leaders.
This process was carried out with ASEPA and coordinated with
appropriate land management agencies of the Territory.