Holocene Landscapes of Waimanalo Bay: Archaeological Investigations at Bellows Beach, O'ahu

Abstract

The late Holocene landscape of the Waimanalo coastal plain on 0 'ahu was substantially transformed by fluctuations in sea level during the past few thousand years as well as by the channel history of Waimanalo (Puha) Stream following the retreat of the mid-Holocene Kapapa Stand of the Sea after about 2,000 years ago. Mapping and dating the distribution of buried alluvial deposits has contributed to a model of the channel history of Waimanalo Stream. Radiocarbon dates of the alluvial deposits calibrate approximately within the range of 1,380 to 1, 610 years before present. These data support reconstruction of the late Holocene geomorphic and cultural landscape of Waimanalo Bay, and the resulting model provides a new context to understand the archaeological record of human settlement and land use in the region. Evidence from the current project suggests Waimanalo Stream once flowed parallel to the coastline for a significant di§tance. As a result, relict channels that formed prior to the arrival of Polynesian colonists would have created an environment with greater agricultural opportunities than if the stream had flowed straight into the sea as it does today. Further, land surfaces along the shoreline as well as behind the coastal dunes may have been alternately scoured or buried by alluvial processes of the stream throughout the Holocene.