Valley Bottomland
The Principal Group and the regions known as Las Sepulturas and El Bosque are situated on the alluvial bottomland of the Copan pocket of the larger Copan Valley. This area constitutes the first alluvial terrace of the Copan pocket and consists of a largely flat surface terrain and highly fertile soils. Alluviation in this zone has been fairly constant over centuries such that much of the Classic period settlement is buried below 40-80 centimeters of alluvial surface deposits. This fact gained prominence in 2001 after PICPAC, a salvage project led by Seiichi Nakamura and funded by Japan, discovered an unexpected royal tomb 900 meters west of the Acropolis. Dating to the Early Classic period (AD 250-600), this find came as a total surprise, appearing in the midst of a road construction project that cut across bottomland terrain 500 meters east of the modern town. Nakamura's discovery reveals that extensive and evocative areas of the city remain unknown, unmapped, and unexplored beneath the alluvium of the valley bottom.
In areas where considerable visible architecture rises above the surface of the bottomland, it is clear that the ancient Maya anticipated, and planned for, floods and changing river levels. We see this in the orientation, location, and height of supporting platforms. The urban sectors of Las Sepulturas and El Bosque, in addition to the Principal Group, were densely settled in antiquity and much of the architecture in these areas has withstood the ravages both of time and water.
River alluvium is not the only source of deposits that cloak surface and subsurface architecture in the bottomlands: slope wash or colluviation from the northern foothills, much of which has been deforested and losing soils since the 19th century, was and remains a significant contributing factor. As we know from excavations in Las Sepulturas, the oldest cultural deposits in the Valley are located in the bottomlands. With conservation and attention to issues of alluviation and colluviation, the future encourages an archaeology that further elaborates what we know regarding the Preclassic period at Copan.