Aguada Zacatal is a reservoir located within a bajo 4 km west of Nakbe, Petén, Guatemala. It is 100 m in diameter and the surrounding berm is approximately 1 m tall. The small Classic period site of Zacatal is adjacent to the aguada. The reservoir's artificial lining prevents dry season desiccation and enhances microfossil preservation. In 1998 a 335 cm sediment core was taken from the center of the reservoir and analyzed for pollen, microscopic charcoal, and total organic matter. Core chronology, based on two AMS radiocarbon determinations, shows the record covers the period from A.D. 695 to present. Only the upper 113 cm contained well-preserved microfossils. The pollen record clearly documents a period of agricultural activity followed by abandonment and forest succession. In the agricultural period (A.D. 695-840), corn pollen is found in conjunction with disturbance indicators. After the abandonment at approximately A.D. 840, the record is dominated by aquatic pollen types and corn pollen is absent. This shift in pollen spectra represents the end of the Classic period.