Excavation sites were chosen where a recently-dammed and expanded Lake Arenal had exposed artifacts on the shoreline, the three major sites out of 39 total being Tronadora Vieja (Costa Rica's earliest dated formative village), Bolivar, and Silencio. The operation-lot system for field control was used in survey and excavation. Volcanological study was able to determine the sequence of prehistoric eruptions of Arenal Volcano and corresponding tephra deposits. When artifacts were found in association with these deposits, they could be independently dated using the predetermined sequence data as well as radiocarbon dating. Over 12,000 potsherds were found and analyzed, with pre-existing pottery sequences from Middle America and Mesoamerica used for comparison. Similarly, 8,755 chipped stone artifacts were found and analyzed, being classified in 18 different categories for comparison with those in existing databases. Only 224 ground stone artifacts were found and analyzed. Botanical remains (carbonized macrofossils, pollen, and phytoliths) were found and analyzed to profile the dietary habits of the region's previous inhabitants. Remote-sensing imagery was also used, and revealed prehistoric footpaths used for human transportation, which were excavated in 38 places by the researchers during the study.